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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
×

2
Evaluation of the Hearing Loss Research Program

The committee was charged with reviewing the Hearing Loss Research Program of the National Institute for Occupational Safety and Health (NIOSH) to evaluate the relevance of its work to improvements in occupational safety and health and the impact that NIOSH research has had in reducing workplace illnesses and injuries. The committee’s review focused on the work of the Hearing Loss Research Program primarily during the period 1996 through 2005. Information about some NIOSH activities during the first few months of 2006 was included in the committee’s review. The committee followed the Framework Document developed by the Committee to Review NIOSH Research Programs (see Appendix A). This review framework directs that relevance be evaluated in terms of the degree of research priority and connection to improvements in workplace protection. It identifies factors to take into account including the frequency and severity of health outcomes and the number of people at risk, the structure of the program, and the degree of consideration of stakeholder input (see Appendix A). Research impact is to be evaluated in terms of its contributions to worker health and safety, to the extent that this can be known or surmised. This chapter presents the results of the committee’s review, reported in the form of qualitative assessments of the relevance and impact of the Hearing Loss Research Program’s research and other activities.

Following the guidance of the Framework Document, the committee carried out its evaluation using the terminology and organization of a logic model adopted by NIOSH to characterize the steps in its work. An examination of goals, inputs,

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
×

activities, and outputs was used to assess the relevance of the program’s research. End outcomes and intermediate outcomes were examined to evaluate the impact of the program’s research. Illustrative examples of each of these terms as used in this report are provided in Box 2-1. The chapter’s sections on relevance and impact each conclude with a summary section with the committee’s overall assessment of and quantitative scores for the relevance or impact of the Hearing Loss Research Program, respectively.

The committee also identified important factors beyond the program’s control that affect its activities and performance. The “external” factors with the broadest reach are discussed before the committee’s assessments of the program’s relevance and impact. External factors that have a more limited effect on the program’s work are noted at appropriate points throughout the discussions of the program’s relevance and impact.

HEARING LOSS RESEARCH PROGRAM GOALS

In 2005, NIOSH established four research goals for the Hearing Loss Research Program, under which programs of varying breadth are being pursued (see Table 2-1). NIOSH also used these four new research goals to organize the primary evidence package provided to the committee and its presentations to the committee. In turn, the committee decided to use the four goals to organize its detailed examination of the Hearing Loss Research Program, while recognizing that these research goals were not in use by the program during most of the period covered by the retrospective assessment. As noted in Chapter 1, the four research goals encompass eight of the nine research needs identified in 1998 (NIOSH, 1998a) that guided the program’s work between 1998 and 2005. The 1998 goals also reflect the priority areas of “hearing loss” and “mixed exposures” that were established in conjunction with the first National Occupational Research Agenda (NORA), as well as some work related to the NORA priority areas of “control technology and personal protective equipment,” “exposure assessment methods,” and “intervention effectiveness research” (NIOSH, 2005d). In the sections that follow, the presentation of the committee’s findings addresses both the overall program and matters concerning individual research goals.

EXTERNAL FACTORS WITH BROAD EFFECTS ON THE HEARING LOSS RESEARCH PROGRAM

The Hearing Loss Research Program operates in an environment shaped by many factors that the program cannot control. Some of these factors are so fundamental to the nature of the program that the committee found it essential to keep them in mind for all aspects of its review.

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
×

BOX 2-1

Logic Model Terms and Examples


Planning Inputs: Stakeholder input, surveillance and intervention data, and risk assessments (e.g., input from Federal Advisory Committee Act panels or the National Occupational Research Agenda research partners, intramural surveillance information, Health Hazard Evaluations [HHEs]).


Production Inputs: Intramural and extramural funding, staffing, management structure, and physical facilities.


Activities: Efforts and work of the program, staff, grantees, and contractors (e.g., surveillance, health effects research, intervention research, health services research, information dissemination, training, and technical assistance).


Outputs: A direct product of a NIOSH research program that is logically related to the achievement of desirable and intended outcomes (e.g., publications in peer-reviewed journals, recommendations, reports, website content, workshops and presentations, databases, educational materials, scales and methods, new technologies, patents, and technical assistance).


Intermediate Outcomes: Related to the program’s association with behaviors and changes at individual, group, and organizational levels in the workplace. An assessment of the worth of NIOSH research and its products by outside stakeholders (e.g., production of standards or regulations based in whole or in part on NIOSH research; attendance at training and education programs sponsored by other organizations; use of publications, technologies, methods, or recommendations by workers, industry, and occupational safety and health professionals in the field; and citations of NIOSH research by industry and academic scientists).


End Outcomes: Improvements in safety and health in the workplace. Defined by measures of health and safety and of impact on processes and programs (e.g., changes related to health, including decreases in injuries, illnesses, or deaths and decreases in exposures due to research in a specific program or subprogram).


External Factors: Actions or forces beyond NIOSH’s control (e.g., by industry, labor, regulators, and other entities) with important bearing on the incorporation in the workplace of NIOSH’s outputs to enhance health and safety.


SOURCE: Framework Document (see Appendix A).

First, there are important limits to the ability of the NIOSH Hearing Loss Research Program to effect change in the workplace. As part of a research agency, the program is in a position to produce knowledge about workplace injuries (i.e., occupational hearing loss), noise hazards, effective hearing protection devices, and hearing conservation practices. NIOSH can also work to promote the application of this knowledge in the workplace. The actual responsibility for minimizing haz-

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
×

TABLE 2-1 Research Goals and Subgoals of the NIOSH Hearing Loss Research Program, as of February 2006

Research Goal 1: Contribute to the Development, Implementation, and Evaluation of Effective Hearing Loss Prevention Programs

1.1.

Develop criteria and recommendations for preventing occupational hearing loss

1.2.

Develop a practical guide for preventing occupational hearing loss

1.3.

Achieve a better understanding of the combined effects of continuous and impulsive noise exposures

1.4.

Develop data management tools for hearing loss prevention programs

1.5.

Develop a hearing loss simulator

1.6.

Develop a survey instrument to evaluate training effectiveness

1.7.

Develop an evaluation checklist for hearing loss prevention programs

1.8.

Develop training focused on improving hearing protection device use

1.9.

Develop a core curriculum in occupational safety and health for high school and post-secondary students that includes a module on hearing loss prevention

1.10.

Develop a hearing protector device compendium

Research Goal 2: Reduce Hearing Loss Through Interventions Targeting Personal Protective Equipment

2.1.

Develop measurement and rating methods that are representative of real-world performance of hearing protection devices

2.2.

Develop hearing protection laboratory and fit-testing methods

2.3.

Evaluate the effectiveness of hearing protection devices against impulsive noise

2.4.

Develop a hearing protection and communication system

2.5.

Develop hearing protection recommendations for noise-exposed hearing-impaired workers

Resear

ch Goal 3: Develop Engineering Controls to Reduce Noise Exposures

3.1.

Reduce noise on continuous mining machines using coated flight bars

3.2.

Reduce noise generated by roof bolting machines using wet and mist drilling

3.3.

Reduce noise exposures to construction workers using a web-based database for powered hand tools

Research Goal 4: Improve Understanding of Occupational Hearing Loss Through Surveillance and Investigation of Risk Factors

4.1.

Determine occupational noise exposure and hearing loss through national surveillance

4.2.

Characterize hearing ability in the general population through national databases

4.3.

Prevent hearing loss from impulsive noise through development of standards and instrumentation

4.4.

Improve detection and prevention of occupational hearing loss by understanding the aging component

4.5.

Prevent hearing loss by understanding the role of genetics in susceptibility to noise

4.6.

Prevent hearing loss from exposure to ototoxic chemicals alone or in combination with noise

SOURCE: NIOSH, 2005f,g,h,i.

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
×

ardous workplace noise environments and ensuring worker compliance with hearing conservation programs lies with employers, who must respond to both economic and regulatory imperatives. Some employers may resist implementation of optimum noise control measures because they are concerned, rightly or wrongly, about the possible economic impact of such measures. Authority to establish and enforce regulations concerning workplace noise exposure and hearing conservation lies with regulatory agencies such as the Occupational Safety and Health Administration (OSHA) and the Mine Safety and Health Administration (MSHA) (both of which are part of the U.S. Department of Labor). NIOSH is expected to make recommendations to these agencies, but the agencies must consider the views of other interested parties, who may have concerns that differ from those of NIOSH.

Gaining and sustaining attention to occupational hearing loss may sometimes be difficult. The condition is relatively slow to emerge, rarely requires immediate medical attention or time lost from work, and is not fatal. Longitudinal studies are often needed to test the effectiveness of new approaches to elements of hearing loss prevention programs, and such studies require willing collaboration by employers and workers. Factors such as changes in management or fiscal conditions may lead companies to withdraw from research collaborations, and turnover in the workforce may compromise the stability of study populations.

Another important consideration is that the Hearing Loss Research Program comprises a collection of activities taking place principally within five organizational units of NIOSH. Thus, the “program” is based on a matrix approach, not on being an identifiable entity in the NIOSH organization chart. In late 2005, NIOSH for the first time designated an executive staff member—Dr. Güner Gürtunca, director of the Pittsburgh Research Laboratory—to serve as the program manager of the Hearing Loss Research Program. Although Dr. Gürtunca and another senior staff member are now expected to monitor and guide the overall program effort, the matrix nature of the Hearing Loss Research Program means that the program manager does not control its budget or program portfolio. The program’s funding level is the sum of the financial resources that individual NIOSH organizational units decide to apply to work on hearing loss prevention or noise control activities. The activities of the intramural program and the equivalent of about 30 professional staff members who carry it out are distributed unequally across three units located in Cincinnati and one in Pittsburgh. The selection and management of extramural projects is based in Atlanta.

The committee was also conscious of the small size of the Hearing Loss Research Program budget. During the period under review, the program’s intramural funding grew from approximately $1.9 million in fiscal year (FY) 1997 to $5.2 million in FY 2005, and its extramural funding from $0.6 million to $2.3 million.

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
×

The total NIOSH budget for FY 2005 was $286 million. By comparison, the FY 2005 budget for the National Institute on Deafness and Other Communication Disorders (NIDCD) in the National Institutes of Health (NIH) was $394.3 million. Of this, research on hearing comprised more than $176 million of the extramural budget of $340.9 million, and roughly 62 percent of the $34 million budgeted for intramural research projects (Rotariu, 2006a,b).

The portfolio, staffing, and funding levels for the Hearing Loss Research Program are also shaped by congressional direction as to the amount of the NIOSH budget that is to be applied to mining safety and health. For FY 2005, the NIOSH Mining Safety and Health Research Program had a budget of $30.7 million and the equivalent of about 260 full-time staff members (NIOSH, 2006h). Approximately $3.6 million was allocated to intramural mining-focused activities (many related to underground coal mining) that are considered to be part of the Hearing Loss Research Program (NIOSH, 2006d). This work accounted for 69 percent of the Hearing Loss Research Program’s intramural funding for that year and 39 percent of about 40 full-time equivalents (FTEs) (15.5 positions). Although the NIOSH mining program no longer carries a separate line item in the federal budget, Congress has directed NIOSH to maintain its current level of research effort in this area. For the Hearing Loss Research Program, this means in practical terms that the program benefits from funding supporting work related to noise control and prevention of hearing loss in the mining sector, but the program does not have discretion to redirect these funds to any of the program’s other activities, which have only a small budget to address the broad goals of the program.

OTHER FACTORS AFFECTING THE HEARING LOSS RESEARCH PROGRAM

Another important factor that the committee came to understand over the course of its information gathering is the degree to which the Hearing Loss Research Program is currently undergoing change as part of NIOSH’s reorganization effort in conjunction with the second decade of NORA (NIOSH, 2006g), as well as by virtue of its self-scrutiny in preparation for this committee’s evaluation. As noted earlier, the program identified new research goals and named new leadership in 2005 as it prepared for this evaluation. Both the name of the program itself and the name of one of its four research goals have been modified since the evaluation began. The committee notes that the revised program name—Hearing Loss Research Program—seems to imply a narrower scope than the original name, Hearing Loss Prevention Program. While the program intends to develop a strategic plan, it has deferred that activity until the conclusion of this evaluation.

A recently increased emphasis on transferring the products of NIOSH re-

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
×

search into workplace application is also important to note. The Office of Research and Technology Transfer was organized in 2004 to help the agency’s scientific investigators better bridge the gap between concept and workplace adoption.

ASSESSMENT OF RELEVANCE

The committee recognizes that hazardous noise exposure and occupational hearing loss represent an important, and underrecognized, threat to the health and safety of U.S. workers in a variety of industries. Although recent data are not available, NIOSH has estimated that at least 4 million workers in the United States may be exposed at work to noise levels that put them at risk of hearing loss (NIOSH, 1998a). NIOSH also has estimated that 9 million workers (some of whom may be among those exposed to hazardous noise) could be at risk as a result of exposure to ototoxic chemicals (NIOSH, 2005d). At present, most hearing loss that results from occupational exposures is irreversible, and poor hearing can compromise both safety and quality of life.

In evaluating the relevance of the work done by the NIOSH Hearing Loss Research Program, the committee has assessed the degree to which the program has led and carried out research in aspects of occupational hearing loss and noise control most relevant to improvements in workplace protection.

If available, surveillance data regarding the nature and extent of the U.S. occupational hearing loss problem would form the basis for identifying priorities and targeting research. The public health approach would direct research efforts toward questions with the most potential to bring benefit to those industrial sectors or special workforce groups with the largest number of workers at risk, the highest risk of occupational hearing loss, or the greatest exposure to its risk factors. Unfortunately, no comprehensive effort to assess the extent of hearing loss among U.S. workers has been carried out for decades. In the absence of such data, both NIOSH and the evaluation committee have only information from more limited surveys, input from stakeholders, and expert judgment as a basis on which to prioritize the national and sector-specific needs in this area.

The Hearing Loss Research Program has included the extramural work1 carried out on hearing loss as part of its program for the purposes of this evaluation. For about a decade, NIOSH has followed the NIH model for administering its

1

Extramural work for the purposes of this report refers to research conducted by investigators outside NIOSH using funding from the Office of Extramural Programs. It does not include work carried out through contracts or cooperative research and development agreements (CRADAs).

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
×

extramural research program. NIOSH develops extramural programs “based on the NORA agenda, r2p [research to practice] initiatives, congressional mandates, and other emerging occupational safety and health priorities. The strategic plans of the individual NIOSH research programs will also influence extramural programs as they are developed and become more prominent in driving the research agenda” (NIOSH, 2005e). Proposals are evaluated for scientific merit by independent panels of experts, and meritorious proposals receive secondary programmatic review by a committee of senior NIOSH scientists. As the result of a “firewall” between intramural programs and the extramural funding selection process, investigators and planners within the intramural program have had little control over the selection of extramural research.

The sections that follow review the four NIOSH Hearing Loss Research Program research areas in turn, providing the committee’s findings with regard to the relevance of the research completed or under way. (Committee evaluation of NIOSH’s targeting of new research is discussed in Chapter 3.) At the end of the review of the four research areas, the committee discusses the relevance of the program as a whole, and provides its quantitative and qualitative evaluation.

Research Goal 1: Contribute to the Development, Implementation, and Evaluation of Effective Hearing Loss Prevention Programs

Goals and Objectives

NIOSH described three objectives for Research Goal 1: (1) providing authoritative, data-driven recommendations and guidelines; (2) developing and/or evaluating hearing loss prevention program “best practices”; and (3) developing, evaluating, and disseminating model training methods, materials, and tools. Each of these areas of effort can have an important role in either developing or synthesizing and conveying research results to minimize workplace exposure to hazardous noise. Thus, the committee found these objectives to be highly relevant to the overall aim of reducing work-related hearing loss. The activities carried out under this research goal are important to disseminating and applying information developed across the entire Hearing Loss Research Program, providing an important means of transfer to the workplace setting.

Planning and Production Inputs

Several important research planning efforts have guided the development of the agenda for this research area over the past decade. Of these, the most important have been “A Proposed National Strategy for the Prevention of Noise-

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
×

Induced Hearing Loss” in 1988 (NIOSH, 1988), which set a course for the program until Criteria for a Recommended Standard: Occupational Noise Exposure (NIOSH, 1998a) was issued in 1998, and the NORA hearing loss prevention initiative in 2001. Most recently, a Futures Workshop was held in April 2005 to plan for the next decade. The Hearing Loss Research Program’s current objectives and work areas bear a reasonable relationship to the earlier planning activities. For example, NIOSH is clearly making efforts to address the two recommendations most closely related to this program area described in the NORA hearing loss initiative of 2001: (1) health communications research focused on training methods and (2) research to evaluate the effectiveness of compliance-driven hearing loss prevention programs. Each of the three planning efforts involved some stakeholder input, and the committee found that research in this program area reflects consistent efforts to develop working relationships with external partners in conducting activities and developing products. The committee recommends, however, that NIOSH expand the base of experts and stakeholders to whom it turns for advice and input to increase both the breadth of the disciplines involved and the depth of the scientific and programmatic expertise of these advisers.

The facilities available for this research area include two audiometric suites, an education and training laboratory, and a mobile audiometric research facility. Since 1997, the financial and staffing resources allocated to this research area have increased. The number of personnel working on projects within this program area, as represented by the number of FTEs, has increased from roughly three to almost eight, and intramural funding has grown from $498,768 to $1,132,932 (see Table 2-2). Although this growth is encouraging, the committee believes that this level of support is not adequate given the importance of and need for the work of this research area. The committee also notes that while the program area has good staffing in audiology and psychology, it lacks the epidemiologic expertise to accomplish the necessary evaluation of the effectiveness of its activities and surveillance for occupational hearing loss and hazardous noise exposure, as discussed further below.

Funding from the NIOSH extramural program expended on projects related to Research Goal 1 has fluctuated over the last decade, from a high in FY 2000 of $559,620 to a low in FY 2004 of $68,612. The funding levels reflect expenditures for from one to three ongoing projects at different times during that period.

Activities and Outputs

NIOSH has undertaken many activities categorized as part of this program area, distributed among the 10 specific areas listed in Table 2-1 and, as a result, has generated many useful publications and products for the field (NIOSH, 2005f).

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
×

TABLE 2-2 NIOSH Hearing Loss Research Program Budget and Staffing by Research Goals

 

FY 1997

FY 1998

FY 1999

FY 2000

Research Goal 1: Contribute to the Development, Implementation, and Evaluation of Effective Hearing Loss Prevention Programs

Intramural

$498,768

$443,552

$882,679

$888,571

FTEs

3.14

5.44

5.99

5.21

Extramural

$195,806

$254,171

$434,103

$559,620

Interagency Agreements

$0

$0

$0

$0

Contracts

$21,800

$214,829

$258,329

$257,680

CRADAs

None

None

None

None

Research Goal 2: Reduce Hearing Loss Through Interventions Targeting Personal Protective Equipment

Intramural

$141, 234

$0

$271,744

$339, 613

FTEs

1.90

0.00

4.30

3.05

Extramural

$0

$38,897

$143,777

$0

Interagency Agreements

$0

$0

$0

$50,000

Contracts

$0

$0

$0

$0

CRADAs

None

None

None

None

Research Goal 3: Develop Engineering Controls to Reduce Noise Exposure

Intramural

$929,618a

$540,419

$466,104

$862,243

FTEs

14.64a

6.75

8.8

11.97

Extramural

$0

$0

$0

$0

Interagency Agreements

$0

$0

$0

$100,000

Contracts

$0

$0

$0

$15,000

CRADAs

None

None

None

None

Research Goal 4: Improve Understanding of Occupational Hearing Loss Through Surveillance and Investigation of Risk Factors

Intramural

$199,448

$164,122

$108,434

$226,573

FTEs

2.75

2.30

1.60

2.33

Extramural

$436,599

$614,942

$977,888

$753,308

Interagency Agreements

$288,888

$288,888

$288,888

$288,888

Contracts

$0

$0

$0

$0

CRADAs

HearSāf

HearSāf

HearSāf

HearSāf

NOTE: CRADA, collaborative research and development agreement; FTE, full-time equivalent.

aThe 1997 FTE figure shown in the table, which is derived from a NIOSH database, differs from the 1997 staffing level recalled by program and budget managers (3 FTEs) (Lotz, 2006b).

SOURCE: NIOSH, 2006a,b,c,d.

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
×

FY 2001

FY 2002

FY 2003

FY 2004

FY 2005

$1,059,249

$901,939

$785,508

$1,166,467

$1,132,932

4.56

3.94

3.39

3.45

7.85

$271,729

$355,700

$110,625

$68,612

$483,270

$0

$0

$0

$0

$0

$282,680

$257,680

$264,280

$262,030

$92,851

None

None

None

None

None

$434,802

$351,846

$731,164

$875,273

$724,586

3.70

3.90

5.10

7.95

8.10

$380,196

$352,879

$0

$0

$183,679

$75,000

$50,000

$113,000

$55,000

$133,000

$0

$73,000

$0

$24,570

$0

None

None

None

None

Earphone

$1,477,267

$1,856,948

$1,753,007

$2,086,163

$2,454,984

15.02

10.3

17.23

21.1

16.27

$50,000

$215,158

$225,600

$141,400

$0

$0

$0

$0

$0

$0

$117,250

$127,250

$187,250

$191,800

$145,000

None

None

None

None

None

$653,150

$944,926

$976,153

$639,372

$453,457

4.55

6.80

7.84

6.22

3.45

$1,089,905

$1,381,223

$1,190,484

$1,488,404

$1,660,459

$288,888

$288,888

$288,888

$359,888

$359,888

$33,750

$58,750

$158,543

$142,800

$0

None

None

None

None

Impulse meter

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
×

Particularly noteworthy among these activities are the development of Criteria for a Recommended Standard: Occupational Noise Exposure (NIOSH, 1998a), and responses to Advanced Notices of Proposed Rulemaking from OSHA and the Department of Transportation regarding hearing conservation programs. The program also provided information to MSHA during the development of its regulation “Health Standards for Occupational Noise Exposure,” issued in 1999 (see MSHA, 1999). In 1996, the Hearing Loss Research Program updated Preventing Occupational Hearing Loss—A Practical Guide, which had first been published in 1990, and the program is now working to repackage the contents of this publication to suit the needs of small businesses. In partnership with the Ford Motor Company and other firms, researchers developed software to support and facilitate hearing loss prevention programs. They developed a hearing loss simulator, made many of their resource materials available on the web, held workshops, and produced NIOSH publications, journal articles, book chapters, presentations, and a television appearance. The impact of this work is discussed later in this chapter.

Committee Comments on Relevance to Occupational Safety and Health

The outputs ascribed by NIOSH to this research area include some of the best-known and most frequently cited products of the Hearing Loss Research Program. Stakeholders attest to their value and usefulness in guiding professionals, employers, and workers in practices considered likely to prevent hearing loss. For example, one comment described Criteria for a Recommended Standard (NIOSH, 1998a) as “seminal and essential,” and another wrote of the criteria document together with Preventing Occupational Hearing Loss—A Practical Guide (NIOSH, 1996) as having “served to push forward the state of the art in hearing loss prevention.” In general, the evaluation committee found the goals and activities related to this research goal to be appropriate and highly relevant. It commends the program area for its increasing emphasis on developing the evidence base for workplace practices to reduce hearing loss, and for productive work with a variety of partners to convey research results to the shop floor.

To further enhance the program’s relevance, the committee urges that more attention be directed toward evaluating the effectiveness of the education and training methods NIOSH has developed. Several evaluation studies described to the committee appear to be testing changes in workers’ knowledge and attitudes about hearing conservation activities (e.g., the hazards of noise, the value of hearing protectors) rather than testing whether workers’ behavior is changing (e.g., using hearing protection more often or more effectively). The committee notes favorably the assessment of the correlation between carpenters’ behavioral intentions and actual hearing protector use (Stephenson, 2001; NIOSH, 2005f) and

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
×

commends the intended monitoring of standard threshold shift (STS)2 rates in shipyard workers as part of research now getting under way (NIOSH, 2005c).

The Hearing Loss Research Program materials emphasize the importance of the hierarchy of controls, giving primacy to engineering controls over other approaches to reducing harmful exposures. The committee agrees with this approach but is concerned that the NIOSH-developed training, tools, and guidelines have placed particular emphasis on administrative controls and personal protective equipment in the form of hearing protection devices, but have not emphasized the role of engineering control of noise sources. Although the “Best Practices Guide” (NIOSH, 1996) contains a chapter on engineering control and stresses its importance, the development and testing of training and materials appear to have been pursued more aggressively for considerations of workers’ use of hearing protection. This may reflect the priorities exhibited by most employers for economic and other reasons. While acknowledging that industry may perceive economic obstacles, the committee urges NIOSH to consider activities that promote low-noise design and noise control engineering approaches, such as the development of education and training materials that promote the importance of and provide technical support for designing and purchasing quiet equipment.

The committee notes that many of the program’s transfer efforts have focused on the construction and mining sectors, and it urges continued efforts to facilitate the transfer of prevention practices to other sectors, as planned with the repackaging of the “Practical Guide” for small businesses.

Another source of some concern for the committee is the seeming lack of appreciation and integration or application of the work carried out via the extramural program that relates to this research goal. None of the eight extramural projects funded in areas relevant to this research goal have been referenced or seemingly built upon by intramural researchers, at least as conveyed by the NIOSH evidence package. The firewall that precludes interaction between intramural researchers and extramural applicants prior to an award (NIOSH, 2005a, 2006e) should not limit productive interaction after the award is made.

Despite these caveats, the committee finds the goals, activities, and outputs of this program area in general to be addressing high-priority subject areas adequately connected to improvements in workplace protection. With limited budget and staff, the program area cannot take on all of the tasks that might seem desirable to an external committee and has done well in its selection of areas to address.

2

A standard threshold shift is defined by OSHA as an average 10 dB or more loss, in one or both ears, relative to the most current baseline audiogram averaged at 2000, 3000 and 4000 Hz (29 C.F.R. 1910.95).

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Research Goal 2: Reduce Hearing Loss Through Interventions Targeting Personal Protective Equipment

Goals and Objectives

For Research Goal 2, NIOSH (2005g) has identified five objectives: (1) developing measurement and rating methods that are representative of the real-world performance of hearing protection devices; (2) developing hearing protection laboratory and fit-testing methods; (3) evaluating the effectiveness of hearing protection devices against impulsive noise; (4) developing a hearing protection and communication system; and (5) developing hearing protection recommendations for noise-exposed hearing-impaired workers. The committee found that these objectives appropriately target research and development that is important to reducing occupational hearing loss. Until or unless low-noise design and noise control engineering approaches are applied universally to eliminate hazardous noise in the workplace, hearing protection devices will continue to be vital to limiting exposure to hazardous noise. All of the goals established by the Hearing Loss Research Program are of ongoing importance to the field, as discussed below.

Planning and Production Inputs

Many of the planning efforts that the Hearing Loss Research Program has engaged in since 1996 have made specific reference to research needs in the area of hearing protection devices. For example, a white paper prepared by NIOSH (1998b) in advance of a March 1998 workshop—Control of Workplace Hazards for the 21st Century: Setting the Research Agenda—which was sponsored by NIOSH, the American Industrial Hygiene Association, and the American Society of Safety Engineers, included among proposed recommendations the development of hearing protection devices that employ active noise control, active level-dependent attenuation technologies, and communication functions and the development of hearing protection devices on the basis of wearer comfort and enhanced speech understanding. (The proceedings from this workshop are still in preparation.) The 2001 NORA hearing loss initiative identified the need for characterization and field evaluation of nonlinear hearing protection devices and the need to implement new technology for improving hearing protection effectiveness. In March 2003, a U.S. Environmental Protection Agency (EPA) Workshop on Hearing Protection Devices, organized by NIOSH, explored three topics: the appropriate fitting protocol to test hearing protection devices for labeling, appropriate methods to assess performance of electronically augmented hearing protection devices, and appropriate methods for calculating the Noise Reduction Rating

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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(NRR) of hearing protection devices. Finally, participants in a May 2003 Best Practices Workshop on Impulsive Noise and Its Effects on Hearing, sponsored by NIOSH and the National Hearing Conservation Association (NHCA), identified research gaps that included basic research on hearing protection devices for impulsive noise and the adequacy of active noise reduction for impulsive noise. Ongoing work in this program area has largely reflected these planning inputs.

The intramural funding and personnel directed toward work in this program area increased from about $140,000 and three FTEs in 1997 to almost $725,000 and eight FTEs in 2005, with a zero budget in 1998 (see Table 2-2). Since 2000, an interagency agreement with EPA has provided additional support totaling $500,000 for research on hearing protection devices with respect to EPA labeling regulations.

Funding from the NIOSH extramural program awarded to projects contributing or related to Research Goal 2 has varied, from none in 1997, 2000, 2003, and 2004 to as much as $380,196 in FY 2001. The funding levels reflect funding for from no projects to one project.

The committee underlines the importance of continuing to support the implementation of realistic hearing protection device attenuation ratings and the development of realistic assessments of field performance. In addition, the committee encourages the agency to increase its research efforts in the less evolved areas of developing a hearing protection and communication system and developing hearing protection recommendations for noise-exposed hearing-impaired workers.

Activities and Outputs

The activities undertaken by the NIOSH Hearing Loss Research Program related to this research goal appear appropriate and of importance to improvements in hearing loss prevention, as well as responsive to the planning inputs described above. The overestimation of hearing protection device performance by the laboratory “experimenter-fit” test procedure has posed difficulties for hearing conservation professionals since the inception of the NRR concept. OSHA requires the use of the NRR despite its basis in an outdated test standard promulgated by EPA in the early 1970s (40 C.F.R. 211.206). Activities in this program area to develop technical evidence for improved measurement and labeling methods will facilitate a badly needed revision of the existing regulation that is likely to help hearing loss prevention program professionals, workers, and employers with the selection of appropriate hearing protection devices. NIOSH’s inter-laboratory studies in this area have resulted in four peer-reviewed publications over 8 years, setting the stage for impacts described later in this chapter (Royster et al., 1996; Berger et al., 1998; Murphy et al., 2002, 2004). Furthermore, the role of Hearing Loss Research Pro-

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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gram staff as technical advisers to EPA in its initiative to revamp the NRR labeling for hearing protection devices is testament to the relevance of their expertise in this program area.

Another major thrust of efforts in this program area is in developing laboratory fit-testing methods. There is an enormous need for a simple fit-testing protocol that can be used in the workplace. A protocol that can be administered onsite will provide employers and hearing loss prevention professionals with a realistic assessment of the amount of noise reduction that a worker’s hearing protection device is providing. The Hearing Loss Research Program’s efforts to develop and compare fit-testing methods and equipment to evaluate them have led to a new tool for researchers and developers, HPDLab. It is anticipated that HPDLab will facilitate research to improve fit-testing protocols that may ultimately be used in the field.

The program area activities and outputs related to the effectiveness of hearing protection devices against impulsive noise are of vital importance to hearing loss prevention. While research endeavors focused on understanding the energy and risk differences between impulsive and continuous noise are pursued through other program areas (see discussion of Research Goal 4), empirical evaluation of the attenuation of impulsive noise by hearing protection devices is also needed. Measuring the performance of different types of hearing protection devices in impulsive noise environments and determining the most effective types for these environments will be especially valuable to law enforcement agencies and the military. In addition, application of this information to the goal of optimizing protection during non-occupational activities with hazardous impulsive noise, such as recreational shooting, may help reduce the amount of noise-induced hearing loss from these types of activities. Thus far, outputs from these efforts have included presentations and publications, Health Hazard Evaluation (HHE) reports to two law enforcement agencies (Tubbs and Murphy, 2003; Harney et al., 2005), and an update of the hearing protection devices compendium (NIOSH, 2000a).

Activities by the Hearing Loss Research Program to develop a combined hearing protection and communication system led to the development of a prototype that has faced challenges in transferring to the workplace via private-sector development. While the committee considers the development work to have been relevant to workplace protection from hazardous noise, its failure to find real-world application demonstrates the need within NIOSH for the capabilities and assistance of the recently established Office of Research and Technology Transfer.

Finally, research begun to explore and address the needs of noise-exposed hearing-impaired workers is relevant and responsive to a research need identified in the 1998 Criteria for a Recommended Standard: Occupational Noise Exposure (NIOSH, 1998a). If successfully developed, practical and easy-to-enforce proto-

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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cols formulated by Hearing Loss Research Program investigators that focus on how to keep such employees safe in noisy environments would be of great benefit to the occupational safety and health community.

Committee Comments on Relevance to Occupational Safety and Health

In summary, the committee finds the goals, activities, and outputs of this program area to be addressing high-priority subject areas adequately connected to improvements in workplace protection. In particular, the work of this program area in support of the revision of the test standard on which the NRR is based and in improving fit-testing methods places the Hearing Loss Research Program at the hub of current research activities concerning the selection and use of hearing protection devices.

Research Goal 3: Develop Engineering Controls to Reduce Noise Exposure

Goals and Objectives

NIOSH (2005h) described three objectives for Research Goal 3: (1) reducing noise on continuous mining machines using coated flight bars; (2) reducing noise generated by roof bolting machines using wet and mist drilling; and (3) reducing noise exposures to construction workers using a web-based database for powered hand tools. The Hearing Loss Research Program evidence materials indicate that these areas for focused research are selected by gathering and analyzing information on noise emission levels to identify the equipment used in the mining and construction industries that produces the highest noise levels and that, where engineering controls do not exist, they are designed, developed, implemented, and tested for the noise-producing equipment (NIOSH, 2005h). Although each of these objectives is appropriate and relevant to the reduction of noise in work environments, they reflect the heavy emphasis of this program area on noise controls for mining, with some additional work in the construction industry. The committee is concerned that this narrow focus neglects noise control needs in other, larger sectors such as manufacturing and small business. Further discussion of the apportionment of noise control work appears later in this section.

Planning Inputs

Circumstances in the mining sector make this an opportune time for an emphasis on noise control in mining. In 2000, MSHA’s rule, Health Standards for Occupational Noise Exposure (30 C.F.R. 62), took effect. This regulation empha-

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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sizes the primacy of engineering controls for preventing noise-induced hearing loss in miners. It does not accept the use of hearing protection devices as a means of compliance with the standard (30 C.F.R. 62.130). As a result, conditions are now more favorable for the implementation of noise controls in the mining industry. In contrast, OSHA’s noise exposure regulation for most industries (29 C.F.R. 1910.95) allows the use of hearing protection devices as a means of reducing exposure to hazardous noise when engineering controls are not feasible. OSHA noise exposure reduction requirements are less strong for the construction industry (29 C.F.R. 1926.52). Employers outside of mining thus have less regulatory incentive to reduce noise at the source.

Several of the planning efforts noted by the NIOSH Hearing Loss Research Program identified research needs pertaining to engineering noise controls that presumably served as planning inputs for this research area. “A Proposed National Strategy for the Prevention of Noise-Induced Hearing Loss” (NIOSH, 1988) identified as long-term regulatory objectives the development of national consensus standards to provide noise labels for new equipment and the reestablishment of the EPA program to implement provisions for product noise labeling required by the 1972 Noise Control Act. In the area of information dissemination, the proposed national strategy noted the need for development of a curriculum model to provide guidelines for buying equipment that meets federal regulations for sound power output, dissemination of guidelines showing employers how to use procurement specifications to induce manufacturers to reduce the sound power output of their machinery, and encouragement of NIOSH-supported Educational Resource Centers and other educational institutions to place more emphasis on noise control and the health effects of noise. Identified as a long-term objective was updating existing manuals for noise control products and compendia of engineering solutions in order to develop a catalog intended for health and safety practitioners who are not noise control specialists.

Criteria for a Recommended Standard: Occupational Noise Exposure (NIOSH, 1998a) names noise control as one of nine research needs to be emphasized and recommends the creation of a database of effective solutions or best practices. Similarly, the Hearing Loss Research Program’s large program proposal in 2000 also identified the need to catalog and evaluate noise control techniques to create an “encyclopedia of effective noise control technology” for use by industry (NIOSH, 2000b).

The workshop Control of Workplace Hazards for the 21st Century: Setting the Research Agenda, held March 10–12, 1998, ostensibly stimulated the formulation of a national plan for research on new strategies to control existing health and safety hazards in the workplace and to anticipate and prevent emerging problems. According to the Hearing Loss Research Program evidence package, the workshop

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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proceedings are still in final preparation to be published on the NIOSH website, so their role as a planning input to this research area is not clear and may have been limited. A white paper drafted in advance of the meeting noted tentative recommendations that included evaluating current and legacy noise control technologies, developing databases to guide selection of retrofit or new noise control technologies, conducting joint research or demonstration projects to fill technology gaps and evaluate new emerging technology, and adopting voluntary noise standards to label products used in the workplace (NIOSH, 1998b).

The Mining Research Plan was recently completed as an overall strategic plan for the NIOSH Mining Safety and Health Research Program (see NIOSH, 2006h). It identifies seven strategic goals, of which Strategic Goal 2 is “Reduce noise-induced hearing loss in the mining industry.” One of four intermediate goals of this strategic goal is “developing engineering noise control technologies applicable to surface and underground mining equipment.”

Finally, a Futures Workshop was held April 7–8, 2005, and cosponsored by NHCA. The summary of this workshop is not yet available, but among the research needs identified at the meeting were developing basic guidelines on engineering controls and the maintenance of those controls, providing leadership to encourage noise control education in undergraduate engineering programs, publishing available noise control solutions, developing engineering controls for small businesses, and encouraging manufacturers to provide noise labels (NIOSH, 2006f).

NIOSH notes the importance of outside review and stakeholder input to its planning and review activities. However, the committee finds that the breadth and depth of expert input drawn upon are not sufficient, either in general or for this program area in particular, which appears to be somewhat isolated from the wider noise control technical community. For example, the proposal for the NORA-funded project of 2001 included a substantial noise control engineering component entitled “Definition and Assessment of Engineering Noise Controls.” The proposal was reviewed by two subject matter experts who had some concerns about it, but it is not clear that those concerns were addressed. External experts on the final review team for the overall NORA Hearing Loss Research Program proposal included no one with an industrial or product noise control background. The 2005 Futures Workshop included only six external speakers, only one of whom was from the noise control field.

NIOSH seems to have sought extensive input from the mining community on mining-related tasks, but this partnership might be broadened further, for instance with inclusion of participants from mine machinery rebuilding shops who could provide additional perspectives on incorporating noise control retrofits on old machines (since older mining machines are often rebuilt rather than dis-

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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carded). It does not appear that the construction community or any other stakeholder or expert group was involved in developing the power tools database project. To the extent that industry can be persuaded to participate, its involvement may strengthen the relevance of this project. Industry participation has not been evident to date.

The committee acknowledges the challenge NIOSH faces in balancing the sometimes-competing or conflicting interests of different stakeholder groups. It is difficult to maintain a collaborative and attentive relationship with multiple stakeholders when all feel that NIOSH ought to consider their needs and status to be of the highest priority. For example, during a briefing to the committee, MSHA expressed the wish that NIOSH afford it “premier standing” as a stakeholder.

The Hearing Loss Research Program has two principal groups of stakeholders. First are the individuals and organizations in the business, labor, and public health communities outside the federal government. NIOSH needs strong relationships with these groups to accomplish its mission. They provide NIOSH with access to the workplace, ideas for programs and priorities, review of and response to research activities, and political support. Second are MSHA and OSHA, the regulatory agencies that by statute have a special relationship with NIOSH. NIOSH has responsibility for making “recommendations concerning new or improved occupational safety and health standards” that “shall immediately be forwarded to the Secretary of Labor” (U.S. Congress, 1970). Although NIOSH needs strong collaborative relationships with all of these groups, the Occupational Safety and Health Act seems to expect NIOSH to give some deference to the views of OSHA and MSHA while at the same time remaining independent, open, and responsive to other stakeholders. Thus, some accommodation to MSHA’s statutory role and needs is in order, but the committee would not consider it appropriate for NIOSH to afford MSHA “premier” status.

Additional planning or information inputs from which the noise control engineering program might benefit further are the bodies of work carried out by the former Bureau of Mines and by MSHA. The Bureau of Mines was active in noise control engineering research in the 1970s, investing approximately $5 million on projects carried out by well-known and respected consultants. Although NIOSH indicated that nothing in the Bureau of Mines noise archives was worth assimilating into the current NIOSH mining noise control effort, the committee encourages further review, either for successful outcomes that can be applied or as a starting point for future research. Similarly, additional examination of work completed by MSHA might also prove valuable to NIOSH researchers and help reduce the risk of needlessly re-tackling long-standing problems.

As with the other Hearing Loss Research Program research goals, the lack of surveillance data on which to base priorities is an important gap in information

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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available for planning regarding noise control needs in both mining and other sectors. Data cited by the program are outdated or weak, although there is an ongoing effort within the mining program to gather cross-sectional noise exposure data (Bauer and Kohler, 2000; NIOSH, 2005b). Additional strong surveillance information is needed across industrial sectors to help in the prioritization and planning of research efforts.

With regard to planning inputs, the research in this program area has been responsive to the current regulatory environment in mining and to many Hearing Loss Research Program planning documents, but has drawn upon limited relevant expertise and surveillance data in planning its activities. The committee encourages continued and improved collaborative planning among the program’s intramural researchers and with regulatory agencies and increased involvement of product noise control technical experts in such planning efforts.

Production Inputs

One of the most important production inputs for this research area results from an external factor described earlier in this chapter. Funding designated by Congress for spending on mining health and safety issues cannot be redirected to health problems in other industry sectors, despite information from surveillance data, experts, or stakeholders that might support other priorities within the broader field of workplace noise control and hearing loss. Given these circumstances, the committee advocates maximizing research and development that might prove applicable outside as well as within the mining sector.

The transfer of the U.S. Bureau of Mines health and safety research to NIOSH in 1996 was followed by a substantial increase in the size of the Hearing Loss Research Program staff and its effort in noise control engineering. Intramural funding for the program area grew over the last decade to $2,454,984 in FY 2005. Over the same period, the number of personnel in terms of FTEs varied from as few as 3 in FY 1997 to more than 21 in FY 2004 (see Table 2-2).

The growth in program resources resulted primarily from two factors. Engineering noise control work, particularly in the mining sector, increased due to both external factors and program management decisions. As noted earlier, Congress directed that funding specifically support mining research. In addition, the MSHA noise regulation published in 1999 created new opportunities for partnerships and research in mining, and NIOSH management responded by reassigning researchers to increase the resources directed at the noise-induced hearing loss issue in mining. In 1997, the Hearing Loss Research Program had fewer than three employees partially focused on engineering noise control research, primarily in mining.

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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While the additional staff assigned to work on engineering noise control since 1997 brought expertise in mining engineering, they had little if any experience in noise control. Noise control engineering is a subspecialty of acoustical engineering and is not easily or quickly mastered. Designing robust and effective noise control engineering solutions that are not merely applications of existing strategies requires extensive engineering education and experience in the field. Source noise control (the appropriate approach for reducing noise emissions of mining and power tool equipment) is the most technically sophisticated and challenging noise control approach and one that is not likely to be implemented successfully by the simple application of concepts found in a catalog or compendium.

Although the committee commends the efforts of Hearing Loss Research Program management to increase the capabilities of its staff by supporting graduate education in noise control for some engineers, this approach can supplement but is not a substitute for recruitment of senior-level researchers with demonstrated world-class expertise in the desired focus area. The committee believes that such a step is necessary for NIOSH to play the national leadership role in industrial and product noise control stated in its mission.

Despite healthy funding for the engineering noise control efforts directed to mining, minimal funds were allocated for the power tool noise control design projects, which were undertaken as class projects supported by small grants to five universities. Although training opportunities such as these projects are important, greater investment in the work of product noise control design experts is likely to be required in order to generate robust and effective noise control designs that are acceptable to manufacturers and likely to be implemented.

Funding from the NIOSH extramural program for projects related to Research Goal 3 totaled $632,000 between FY 2001 and FY 2004 for two projects focused on active noise cancellation. These efforts (and any resulting output) do not appear to have been integrated into the work of the intramural program, even though one of the two projects involved mining equipment.

Three laboratory facilities are involved in noise emission measurement activities related to this research goal. Two of these have been able to adequately support the goals of the program, while the other has met with significant challenges. The reverberation chamber at the Pittsburgh Research Laboratory was recently accredited by the National Voluntary Laboratory Accreditation Program (NVLAP) for sound power-level determinations in accordance with ISO (International Organization for Standardization) 3741 (ISO, 1999) and ANSI (American National Standards Institute) S12.51 (ANSI, 2002). The large hemi-anechoic chamber has just been completed. The Pittsburgh noise control team indicated its intention to earn NVLAP accreditation for test procedures that will be developed for this facility.

In contrast, the hemi-anechoic chamber at the University of Cincinnati ap-

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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pears to be too small for some power tool measurements or to measure certain tools under load. That chamber is not NVLAP-accredited, which would be appropriate for the nature of the work being performed (where outputs would be expected to be used as the basis of third-party product noise declarations and purchase specifications, etc.). The committee has concerns about the conduct of operations at the University of Cincinnati laboratory that extend beyond accreditation, however. Data generated for the purposes of consensus standards, comparison of commercial equipment, or publicly available references for decision making should be carried out according to standardized documented procedures, with a professional level of accuracy and repeatability that can be quantified and guaranteed. It was not clear to the committee that the work met these standards.

Activities and Outputs

Projects to reduce noise on continuous mining machines and noise generated by roof bolting machines using wet and mist drilling are well under way and have generated outputs in the form of new technologies that have been described in trade journals and conference proceedings (e.g., “Noise Controls for Continuous Miners” [Kovalchik et al., 2002]). The necessary next steps to validate these technologies with full-shift noise exposure monitoring (not merely sound emission measurements) under mining conditions in a working mine are very important and highly relevant to the reduction of hearing loss in mines where they might be implemented. Should these technologies qualify as “technically achievable” according to MSHA, they are much more likely to be used, as discussed later in this chapter.

Collection of baseline power tool noise emission measurements is a necessary precursor to any product noise control design project. However, the Hearing Loss Research Program’s current online power tool database is of limited value because of uncertainty in how the measurements were made (the database contains results that were obtained in accordance with a test standard that specifies unloaded conditions for some tools and loaded conditions for others, and the operating conditions are not indicated in the database) and limitations of the laboratory facility and operations where the measurements were acquired. Expert, experienced professionals should carry out this work in an NVLAP-accredited laboratory facility to ensure its quality and credibility.

NIOSH has used small contracts to involve engineering students at five universities in designing acoustical engineering controls to reduce noise from small construction tools (Hayden, 2004). Student research projects are worthwhile and important activities, but they are not a substitute for focused research by experienced professionals, whether on the NIOSH staff, at universities, or in the private

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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sector. In supporting the small student projects, the Hearing Loss Research Program has made an effort to contribute to the development of noise control engineering capability among college students, but the program also needs more systematic plans to promote the efficient development and transfer of robust noise control designs that can be cost-effectively and realistically implemented, manufactured, and accepted by the end user community.

Several other activities related to this program area have not yet produced outputs. Among them are updates of the Industrial Noise Control Manual (NIOSH, 1978) and the Compendium of Materials for Noise Control (NIOSH, 1980). OSHA has provided $100,000 toward the effort to produce a resource with standard noise control solutions useful even for people outside the discipline of noise control (NIOSH, 2006c). Another anticipated output is the “Noise Control Guidebook for Underground Metal Mines,” which was developed as part of the large NORA-funded project begun in 2001. These activities are more difficult to successfully complete than might appear because source noise control, in particular, involves expert judgments that cannot readily be reduced to generic examples for the purpose of cataloging solutions.

Finally, as far as could be ascertained, the outputs from the two extramural projects were a final report (Hodgson and Li, 2004), a master’s degree thesis (Rai, 2005), and a paper (Rai et al., 2005).

Committee Comments on Relevance to Occupational Safety and Health

Although the true extent of noise-induced hearing loss in the mining sector is not well defined, the committee finds that the amount of funding that has been expended to study a very narrow range of noise control problems, in a small segment of workers, reflects an imbalance when considering the relative importance of those problems in the context of the broader industrial noise problem. Within the Hearing Loss Research Program, the focus on mining appears to short-change other occupational sectors and pose a risk that emerging issues will not be identified.

The prioritization within this research goal reflects the results of congressional targeting of resources toward health and safety challenges in mining. Given this external factor, the committee appreciates that some of these resources are being directed to “dual-use” applications that might bring benefits to other industrial sectors, but more efforts need to be undertaken in this direction. The committee urges the program to work actively to transfer the information beyond the mining sector to other application opportunities (see Chapter 4).

The committee understands that the noise control work at the Pittsburgh facility represents a nascent effort that is still ramping up in expertise, capability,

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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and facilities. The committee urges that senior-level expertise be recruited to provide the technical leadership needed in this important and specialized area.

Stakeholder relationships are important for providing NIOSH with input to the planning process, cooperation for workplace studies, and partnerships for the actual use of NIOSH-developed technologies or materials. Particularly in the mining sector, the Hearing Loss Research Program has done a good job of cultivating the strong relationships with stakeholders that are crucial for carrying out relevant research and development work that is validated in real-world settings. The committee urges the development of better ties to other relevant stakeholders and sources of noise control engineering expertise. In the same vein, the committee urges better awareness and integration of relevant work carried out through the extramural funding program.

In general, the committee finds the goals, activities, and outputs of this program area to be focused on subject areas of lesser priority than desirable, even taking into account the strictures limiting much of the spending to the mining sector. The targeted funding does not preclude other Hearing Loss Research Program efforts from reaping greater benefit from the work done and otherwise making a greater contribution to engineering controls for other sectors.

Research Goal 4: Improve Understanding of Occupational Hearing Loss Through Surveillance and Investigation of Risk Factors

Goals and Objectives

The six objectives described by NIOSH (2005i) for Research Goal 4 are (1) determining occupational noise exposure and hearing loss through national surveillance; (2) characterizing hearing ability in the general population through national databases; (3) preventing hearing loss from impulsive noise through development of standards and instrumentation; (4) improving detection and prevention of occupational hearing loss by understanding the aging component; (5) preventing hearing loss by understanding the role of genetics in susceptibility to noise; and (6) preventing hearing loss from exposure to ototoxic chemicals alone or in combination with noise. The committee found the main objective (establishing effective surveillance systems to monitor exposures in the workplace and the incidence of hearing loss in workers) highly relevant to reducing occupational hearing loss. If designed appropriately, such systems may also help to address questions related to the aging workforce. Research to develop standards and instrumentation for preventing hearing loss from impulsive noise and to prevent hearing loss from exposure to ototoxic chemicals is also relevant to the reduction of work-related hearing loss.

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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The committee had less confidence in the relevance of research objectives 2, 4, and 5 to the overall NIOSH Hearing Loss Research Program mission “to provide national and world leadership to reduce the prevalence of occupational hearing loss through a focused program of research and prevention.” Although the hearing status of the general population, the role of aging in hearing loss, and the genetics of hearing loss are important research questions, the committee saw a need for NIOSH to emphasize the work-related aspect of these topics. Basic science studies pertaining to the genetic and aging aspects of hearing loss may have implications for the workplace, but they could be better supported and conducted through organizations such as NIH, with NIOSH collaborating in or building on such studies in ways that focus on workers and the workplace. Similarly, data on the hearing ability of the general population is of interest for comparison with occupational groups, but it may be more appropriate for NIOSH, with its focus on worker health, to rely more heavily on NIH or others to assemble the data for the general population. In the committee’s view, the Hearing Loss Research Program should actively monitor relevant research being conducted or supported by NIH and, when appropriate, should strive to build on findings from that work.

Planning Inputs

Several planning activities and documents noted as important by the Hearing Loss Research Program have identified research needs addressed in this program area. “A Proposed National Strategy for the Prevention of Noise-Induced Hearing Loss” (NIOSH, 1988) noted short-term objectives, including analyzing data collected under the OSHA Hearing Conservation Amendment to evaluate the effectiveness of regulations. Long-term objectives included “collect[ing] hearing data for populations not exposed to occupational noise as a baseline for comparing the hearing of groups exposed to noise. Norms should be established as a function of geographic region, sex, race, age, etc.” Other long-term objectives included conducting research to better define the relative hazard of different kinds of noise (impulse, impact, intermittent, etc.); determining the degree to which noise interacts with other agents in the work environment (solvents, metals, prescription drugs, etc.) to affect hearing; and describing the physiologic mechanisms associated with noise-induced hearing loss. Criteria for a Recommended Standard: Occupational Noise Exposure (NIOSH, 1998a) included impulsive noise, auditory effects of ototoxic chemical exposures, and exposure monitoring among the nine research needs identified.

The proposal prepared by the Hearing Loss Research Program and funded in 2001 through NORA was intended to “augment specific areas of the overall program that needed to be strengthened” (NIOSH, 2005d). The long-term objectives

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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identified for the 5-year project included assessing the prevalence of occupational noise exposure and related hearing sensitivity, identifying critical gaps in the noise and hearing loss knowledge base, and conducting or supporting gap-filling research and developing data and recommendations to support standards and rule-making bodies (NIOSH, 2005d).

In April 2002, the Hearing Loss Research Program together with NHCA held a Best Practices Workshop on the Combined Effects of Chemicals and Noise on Hearing (NIOSH, 2005k), with 13 outside speakers and 77 attendees. During a 2003 Best Practices Workshop on Impulsive Noise and Its Effects on Hearing (NIOSH, 2005k), participants (12 outside speakers, 43 attendees) identified five research needs for future studies: (1) instruments and standards for measurement and evaluation of impulsive sounds; (2) international consensus on descriptors for impulsive sounds and procedures for applying results from tests on animals to models for effects on humans; (3) international consensus on procedures to evaluate the effectiveness of hearing protection devices and engineering noise controls to reduce hearing loss; (4) understanding of hearing impairment resulting from exposure to impulsive sounds; and (5) damage risk criteria for impulsive sounds (Kardous et al., 2005). The 2005 Futures Workshop (with 25 NIOSH and 6 external participants) was also a part of the Hearing Loss Research Program’s planning processes.

Several of the objectives for this program area were identified as research needs in planning documents or were the subject of conferences, but it is unclear from the material provided how these events have contributed to the design and implementation of current and future research activities under this program area. Although some stakeholder and outside expert input has been obtained, it appears that there are relatively small numbers of experts from outside NIOSH engaged in these planning activities. The Hearing Loss Research Program is strongly encouraged to expand its network of external advisers to better represent the current applied and basic knowledge base on noise-induced hearing loss.

Production Inputs

The budget devoted to this program area has grown considerably in the last 10 years, with the majority of these dollars channeled to extramural initiatives. Intramural funding allocated to this area varied from $108,434 to $976,153 during this time, with $453,457 budgeted for FY 2005 (see Table 2-2).

Between 1997 and 2005, an interagency agreement between the National Institute on Deafness and Other Communication Disorders and the National Center for Health Statistics provided $2.1 million to support the adult audiometry examinations that were conducted as part of the National Health and Nutrition Exami-

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
×

nation Survey (NHANES) and overseen by the Hearing Loss Research Program. NIDCD also provided $71,000 for each of FY 2004–2005 and FY 2005–2006 to support continued Hearing Loss Research Program work on the NHANES effort via a contractor.

Only a small number of FTEs at NIOSH have been engaged in Research Goal 4 activities, ranging from fewer than 2 to nearly 8 over the past decade, with the level at 3.45 in FY 2005. Given the stated major focus on surveillance and traditional epidemiologic studies, it is notable that no epidemiologist is currently involved in these activities. This is a marked contrast to other program areas in NIOSH that are known for their strong epidemiologic expertise. The committee encourages the addition of epidemiologic expertise to improve the quality of the surveillance activities within the Hearing Loss Research Program.

Extramural funding for this research area nearly quadrupled over the decade, from $436,599 in FY 1997 to $1,660,459 in FY 2005, at the same time that the number of projects funded increased from two to seven. The Hearing Loss Research Program has relied on the investigator-initiated pipeline rather than issuing requests for targeted extramural proposals.

Overall, the resources of this program area with respect to the availability of a sufficient budget, staff, and essential expertise are not adequate for its broad scope.

Activities and Outputs

As acknowledged by NIOSH, the lack of surveillance data for noise exposure or occupational hearing loss is a fundamental knowledge gap (NIOSH, 2005i). The committee views the Hearing Loss Research Program goal to “determine occupational noise exposure and hearing loss through national surveillance” as crucial and highly relevant, and in need of focused and well-designed activities to improve upon the current situation.

For many years, the Hearing Loss Research Program has been engaged in monitoring hearing in workers through health hazard evaluations, targeted industrial surveys, statewide monitoring (Michigan), and efforts to have hearing loss reported separately under the OSHA recordability standard. Some of these initiatives have involved program personnel directly in the methods and monitoring of data quality and others have not. These activities have led to outputs in the form of contributions to the Worker Health Chartbook (NIOSH, 2004), annual reports from a state-based surveillance program (http://oem.msu.edu/sensor.asp) (Michigan State University, 2004), software for more efficient use of audiometric databases, NIOSH reports, and several journal publications.

Despite these contributions, there remains a lack of reliable person-level data on the incidence of hearing loss among workers, in part because of historical

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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approaches to hearing loss prevention that have focused on standard threshold shifts, which can occur more than once in a person. In addition, the rates of recordable standard threshold shifts now being reported by the Bureau of Labor Statistics (BLS) use FTEs for denominators. Under this model, two part-time workers may equal one FTE in the denominator and two cases of hearing loss in the numerator. As a result, data from BLS can provide only an approximation of the public health burden of occupational hearing loss, temporal trends are difficult to interpret, and the success of prevention efforts cannot be measured accurately.

In addition, the primary model in which hearing loss in an employed person is attributed exclusively to workplace noise ignores the potential contributions of exposures accrued outside of or unrelated to work, the effects of chemical exposures at work, or aging and may lead to an overestimate of the amount of occupational noise-related hearing loss. On the other hand, poor measures of noise exposure may lead to underestimates of noise-related damage to the auditory system. In the absence of good surveillance data, NIOSH has relied for many years on estimates originally dating from the 1980s and unpublished reanalyses when describing the dimensions of the hearing loss problem. Rather than repeatedly citing these unreliable estimates, the Hearing Loss Research Program needs to take concrete steps to address the lack of good numbers and published analyses.

The Hearing Loss Research Program has received feedback about its lack of surveillance efforts before. One of the reviewers of the program’s large proposal for NORA funding in 2001 commented: “Unfortunately the proposed program does not include any attempt to assess the methodology for developing a surveillance system for work-related noise induced hearing loss. Such a system is crucial to assess the burden of noise-induced hearing loss, evaluate the effectiveness of hearing conservation programs, education and enforcement activity and study trends in the disease…. It is a major deficiency in the NIOSH noise program that no research project addresses developing methods of conducting national surveillance” (NIOSH, 2001).

Most of the Hearing Loss Research Program’s recent activities to measure occupational noise exposure appear to be focused on supporting studies of specific worker groups such as miners, Washington State construction workers, those on Brazilian fishing boats, and others. Since it is not clear how generalizable these results are to other occupational settings or to the U.S. worker, it appears that surveillance of current noise exposures is inadequate. The number of workers with significant exposure to noise is simply not known, nor is there an effective mechanism for either determining change over time or identifying subgroups of workers who are at highest risk. Plans for national surveillance of workplace noise exposures were not presented.

Hearing Loss Research Program activities to help characterize hearing ability

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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in the general population through national databases are carried out largely through partnerships. The program’s audiologists have provided technical oversight of the audiometry component of NHANES as it conducts cross-sectional studies of hearing across all ages. Outputs in the form of NHANES audiometric datasets are now available to NIOSH researchers and others for analysis.

The committee is appreciative of the strategy of partnering with other agencies to ensure that high-quality data about hearing in the general population are available for the nation, and the involvement of the program’s hearing professionals in the NHANES study is further recognition of their technical expertise. However, the Hearing Loss Research Program should participate in these activities only to the extent that they are also able to develop appropriate initiatives to understand the risk of occupational hearing loss.

Furthermore, the expectations from these partnerships are not necessarily appropriate. For example, the goal to use NHANES data as a non–noise-exposed reference population is not realistic. Many of the NHANES subjects are younger or older than the working population, and among those in the correct age range, many will have exposure to occupational or other noise. The committee is concerned that the sample size of non–noise-exposed individuals of working age is not sufficiently large for statistical rigor. Also, while the NHANES data will yield valuable information about the prevalence of hearing loss in the general population, it was not clear to the committee that this is germane to the primary mission of the Hearing Loss Research Program. Because of the well-known “healthy worker effect,” comparisons between employed workers and the general population may not accurately measure the impact of work-related exposures on hearing health.

The Hearing Loss Research Program also hopes to gain information on the effects of aging from NHANES. NIOSH researchers assert that the data “allow for direct measurement of hearing loss due to aging in the population” (NIOSH, 2005i), but this statement reflects an inaccurate understanding of the strengths and limitations of the NHANES study design. Although the study will provide high-quality data on hearing thresholds in individuals of various ages, cross-sectional data do not provide measures of aging effects; only longitudinal data can answer that question.

The program’s researchers are also providing technical assistance to studies in a small longitudinal cohort (Fels Longitudinal Study) and to the Age, Gene/ Environment Susceptibility Study (AGES), a longitudinal study of Icelanders. The Fels study collected hearing thresholds and noise exposure information on children and young adults between 1977 and 1983 and will conduct repeat audiometric testing on these former youths (now adults) and their children. Without information about sample size or expected participation rates, the committee is concerned that selection and response biases will limit the utility of the results.

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Furthermore, although studies of Icelanders may contribute knowledge about genetic polymorphisms important in hearing loss and aging in Iceland, it is not clear that this information will be relevant for U.S. workers. Neither of these research activities in selected samples directly addresses concerns about occupational hearing loss, or the goal of characterizing hearing ability in the general population through national surveillance.

The Hearing Loss Research Program has supported activities investigating the prevention of hearing loss from impulsive noise exposure primarily through extramural studies in experimental animal models. In addition, program personnel have evaluated existing acoustic measurement devices and standards and their limitations with regard to impulsive sounds. Current activities include developing new technology for measuring impulsive noise (in part through a cooperative research and development agreement [CRADA] with Larson-Davis, Inc.) and working toward an occupational damage risk criterion for impulsive noise exposure. Outputs have included two HHE reports, a provisional patent on an instrument for monitoring exposure to impulsive noise, a 2003 best-practices workshop on impulsive noise, and numerous peer-reviewed articles extending back 30 years.

Activities related to improving understanding of the aging component of hearing loss have been carried out primarily through a partnership with the University of Cincinnati’s Department of Biological Sciences. Studies in a mouse model of early age-related hearing loss and susceptibility to noise-induced hearing loss have evaluated the impact of noise and aging on hearing and the possibility that dietary antioxidants protect the ear from early hearing loss due to aging. Outputs have included an important publication (Erway et al., 1996) and related articles, presentations, and posters, as well as a conference co-organized by the Hearing Loss Research Program entitled “The Mouse as an Instrument for Hearing Research,” which was held in 2003 at the Jackson Laboratory, Bar Harbor, Maine. The Jackson Laboratory organized a follow-up meeting in 2005, with participation by a NIOSH Hearing Loss Research Program researcher.

Hearing Loss Research Program activities related to understanding the role of genetics in susceptibility to noise include the mouse model work carried out with the University of Cincinnati and AGES, the study of 10,000 Icelanders discussed above, to look for genes for hearing loss.

By far, the most well-developed research area within Research Goal 4 has been the effects of exposure to ototoxic chemicals alone or in combination with noise. The Hearing Loss Research Program has engaged in numerous studies, primarily in other countries, that demonstrate potential ototoxic effects of chemical exposures in the workplace and interactive effects of noise and chemical ototoxins. The research is novel, has been published widely in the mainstream scientific literature, and has begun to influence policy decisions. This research goal and its associated

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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activities are highly relevant to NIOSH’s mission. However, data to determine the magnitude of ototoxic chemical exposures are lacking and need to be sought. The number of U.S. workers exposed, the amount of exposure, and the risk of hearing loss associated with the exposure are not known.

As noted, extramural research represents the largest use of resources for this program area. Some of the projects have been noted above. Over the last decade, these projects have included laboratory animal studies to better predict the consequences of noise exposure, to explore basic mechanisms of noise damage to hearing, to examine interactions of chemical asphyxiants and noise in hearing loss, to apply both a statistical learning machine and a radial basis function neural network to the prediction of noise-induced hearing loss, and to explore the prevention of solvent- and noise-induced hearing loss with antioxidants. Other projects have included a cross-sectional study of hearing acuity and threshold shifts in Hispanic workers, a prospective study of hearing damage among new construction workers, a longitudinal study on effects of noise and solvents on hearing, and the development of a low-cost miniature personal noise dosimeter. All of these efforts represent investigator-initiated research. With the exception of work in the area of ototoxicity, there has been limited effort by intramural researchers to build on the extramural research. To bring more focus to high-priority research topics for occupational hearing loss, the committee recommends that the program consider generating Requests for Applications and Program Announcements to help focus extramural researchers on issues highly relevant to the mission of the Hearing Loss Research Program (see Chapter 4).

Committee Comments on Relevance to Occupational Safety and Health

This program area is the smallest by far of the four research areas in terms of funding and staffing, representing less than 10 percent of the Hearing Loss Research Program intramural budget and FTEs in FY 2005. Nevertheless, Research Goal 4 has the broadest and perhaps the most difficult program objectives to achieve. Taking into account the scale and strengths of the Hearing Loss Research Program, the highest priority should be given to areas that are fundamental to addressing occupational hearing loss. The distinction is captured in the two titles that the Hearing Loss Research Program has used for this goal. The original name was “Contribute to reductions in hearing loss through the understanding of causative mechanisms.” More recently, the program has adopted the current name, “Improve understanding of occupational hearing loss through surveillance and investigation of risk factors.” The committee sees the name change as appropriate, but notes that the emphasis of the work also needs to change to reflect the impor-

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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tance of both surveillance and occupational hearing loss (as opposed to hearing loss in general).

The committee sees the research goals of determining occupational noise exposure and hearing loss through national surveillance, preventing hearing loss from impulsive noise through development of standards and instrumentation, and preventing hearing loss from exposure to ototoxic chemicals as highly relevant to reductions in workplace noise or hearing loss. The challenges described earlier of carrying out effective surveillance in occupational hearing loss and noise exposure necessitate the investment of financial resources and epidemiologic expertise commensurate with the importance of surveillance data to setting priorities for the whole program. The committee recommends a better alignment of allocated resources with the scope of the challenges.

The committee views the objectives and activities related to understanding the aging and genetic components of hearing loss and assessing hearing loss in the general population as less relevant to preventing occupational hearing loss. Although there are important questions to be answered about the relationships between hearing loss, aging, and genetics, the current projects reflect a diffusion of the mission from worker safety to basic science questions, which are less relevant for NIOSH and could be better supported or conducted by other organizations such as NIH. Data that will be generated from audiometric surveys of the general population will be of interest, but cannot meet unrealistic expectations for their usefulness for comparison with occupational populations.

It appeared to the committee that most projects undertaken as part of this research area developed not from strategic planning efforts, but from opportunities offered and initiated by others. While appreciating the leveraging of limited resources that this has represented, the committee recommends an approach to planning based more on Hearing Loss Research Program priorities, for both its intramural and its extramural research. With limited resources, it is important to select opportunities that will directly address the goals of the Hearing Loss Research Program.

In contrast to activities and outputs in other Hearing Loss Research Program areas, there has been less emphasis in this program area on transferring knowledge to key stakeholders. For this research area, the key stakeholders are the scientific community. Analyses of databases that have been influential in determining policy have remained unpublished (Franks, 1996, 1997a,b) and criticisms have gone unanswered (Clark, 1997; Dobie, 1997). The committee emphasizes the importance of publication in peer-reviewed journals as a means to enhance the credibility of the work as well as to communicate findings to other scientists and contribute to the scientific knowledge base.

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
×

The work carried out as part of this research goal includes efforts, particularly related to understanding ototoxins, that are highly relevant to preventing occupational hearing loss. However, the committee finds the goals and activities of this program area to include several lesser-priority subject areas only indirectly connected to workplace protection, while giving insufficient effort and resources to the fundamental needs in surveillance for occupational hearing loss and hazardous noise exposures. Particularly because of its limited resources, it is important that the Hearing Loss Research Program focus on the priorities most closely related to its mission.

OVERALL EVALUATION OF THE RELEVANCE OF THE HEARING LOSS RESEARCH PROGRAM

To arrive at its qualitative evaluation and quantitative score for the relevance of the NIOSH Hearing Loss Research Program, the committee strove to step back from its part-by-part examination of the program as presented above and consider the program as a whole. Doing so raises several issues discussed at the start of this chapter that pertain to the program considered in its entirety: (1) the program is not conceived and planned as a whole, but at present is the sum of parts contributed by several divisions and a laboratory within NIOSH; (2) the largest portion of the program in terms of financial resources and staffing is designated for study of hearing loss prevention in mining, and these resources cannot be redirected to hearing loss needs in other industrial sectors; and (3) the entire program is funded at only $7.5 million, a level dwarfed by the scale of the challenge it faces in helping to facilitate the reduction of work-related hearing loss for the nation.

Acknowledging the factors above, the committee considered various ways to arrive at a single number to convey a measure of the relevance of the total program. The Framework Document (Appendix A) that guided the committee’s evaluation does not prescribe a method to arrive at an overall, quantitative score from the qualitative evaluations of separate program areas. As was apparent from the review of the relevance of each of the four research areas within the total program, the committee found considerable variation in relevance across the components of the program as presented. The committee deliberated carefully about how the various research areas should be weighted, either explicitly or implicitly, in arriving at a final score. In contrast to the approach described later for arriving at a score regarding the impact of the work of the Hearing Loss Research Program, the committee chose to weight all of the program’s activities nearly equally in contemplating the relevance of the work.

The charge to the committee requires an assessment of the relevance of the program’s activities to the improvement of occupational safety and health. The

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Framework Document ties relevance scores to the priority of subject areas and to the degree of connection to improvements in workplace protection (Appendix A). What determines “high priority”? The public health approach to prioritization relies on surveillance data to identify populations or sectors where the greatest good can be accomplished with the least effort. The Hearing Loss Research Program acknowledges the absence of current data on the incidence of occupational hearing loss or prevalence of hazardous noise exposure in the workplace, citing in its stead data that are old or weak (or, at best, unpublished) to justify the importance of this occupational health problem.

Lacking these data, one of the most important influences on the Hearing Loss Research Program in its prioritization process has been input from stakeholders, including partners from industry, labor, regulatory agencies, and professional associations. In both the NORA process and other planning activities, NIOSH has involved stakeholders in an effort to discern and prioritize research needs. Stakeholders and partners were involved in the development of “A Proposed National Strategy for the Prevention of Noise-Induced Hearing Loss” (NIOSH, 1988), which guided research in the Hearing Loss Research Program for a decade, and in identification of the research needs articulated in Criteria for a Recommended Standard: Occupational Noise Exposure (NIOSH, 1998a). Mining partners such as the United Mineworkers of America, the Bituminous Coal Operators Association, the National Mining Association, Joy Mining Machinery, MSHA, and others make up “the Noise Partnership” that facilitates research on noise reduction of mining equipment (NIOSH, 2005j). These partners also provided important input to the development of the Mining Research Plan, in which “Reduce noise-induced hearing loss in the mining industry” is one of seven strategic goals (Lotz, 2006a). Most recently, the Hearing Loss Research Program involved a limited number of external participants in a Futures Workshop to help set research priorities.

Given the importance of stakeholders to the Hearing Loss Research Program’s priority setting, the committee has concerns about the size of the community to which NIOSH turns for input, and it urges an effort to draw on a broader and deeper set of people from both scientific and other communities to help make this an outstanding program (see Chapter 4).

An assessment of relevance must take into account the input and interests of stakeholders. Stakeholder involvement and input into NIOSH research prioritization were most apparent and laudable in the area of development, implementation, and evaluation of hearing loss prevention programs, at least as manifested by participation in conferences and workshops. The committee received input from a variety of stakeholders in the course of its information gathering (see Chapter 1 and Appendix B), including representatives from labor, industry, regulatory agencies, professional organizations, and academic researchers. With some exceptions

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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noted elsewhere in this report, stakeholders (many of whom have partnered or collaborated with the Hearing Loss Research Program) expressed positive opinions about the relevance and appropriateness of the program’s research efforts.

The committee notes that despite the Hearing Loss Research Program’s intentions to develop a strategic plan in the future, it is evident—and even noted candidly in the evidence package (NIOSH, 2005d)—that management of the program over the last decade has taken place more by opportunity than by objective. For a research organization as small as the Hearing Loss Research Program, “management by objective” will be difficult. NIOSH depends on employers to enable access to appropriate study populations; therefore the program may not have the opportunity to study some of the most hazardous settings, and the continuity of the work that is undertaken can be interrupted with changes in management or lower-level staff (e.g., a project with Ford [NIOSH, 2005f]). In addition, by virtue of its role as a research rather than a regulatory organization, the program may be able to influence, but cannot set, the agenda for development of recommended regulations. Management by opportunity has also had its merits—in the past the program has skillfully leveraged its limited resources by collaborating with others.

The committee urges a balance. The Hearing Loss Research Program should seize opportunities in the context of a plan that keeps its efforts focused on the most relevant work. Using the limited surveillance information available, information from stakeholders, and its members’ expert judgment, the committee found that the Hearing Loss Research Program mission and four main research goals were highly relevant to the overall aim of reducing occupational hearing loss. However, the committee considered some of the objectives or activities within these broad research areas to be less relevant to the goal of reducing work-related hearing loss.

On the basis of its review, the committee has assigned a score of 3 for the relevance of the NIOSH Hearing Loss Research Program. According to the Framework Document, a score of 3 indicates that research focuses on lesser priorities and is loosely or only indirectly connected to workplace protection (see Box 2-2).

ASSESSMENT OF IMPACT

End Outcomes

In considering the impact of the work by the NIOSH Hearing Loss Research Program, it is necessary to recognize that NIOSH and its research programs can never be expected to impose the changes in the workplace or in the behavior of workers that are necessary to reduce or prevent adverse health outcomes. What the program can be expected to do is to contribute knowledge about hazards and the

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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BOX 2-2

Scale for Rating Program Relevance

5

=

Research is in highest-priority subject areas and highly relevant to improvements in workplace protection; research results in, and NIOSH is engaged in, transfer activities at a significant level (highest rating).

4

=

Research is in high-priority subject area and adequately connected to improvements in workplace protection; research results in, and NIOSH is engaged in, transfer activities.

3

=

Research focuses on lesser priorities and is loosely or only indirectly connected to workplace protection; NIOSH is not significantly involved in transfer activities.

2

=

Research program is not well integrated or well focused on priorities and is not clearly connected to workplace protection and inadequately connected to transfer activities.

1

=

Research in the research program is an ad hoc collection of projects, is not integrated into a program, and is not likely to improve workplace safety or health.

prevention of adverse outcomes and to promote plausible, evidence-based, risk-reducing actions by others, including regulatory authorities, equipment manufacturers, employers, and workers. Such actions constitute intermediate outcomes, and the committee relied on them in making its assessment of the impact of the Hearing Loss Research Program.

Nevertheless, it would be desirable to be able to consider the impact of a NIOSH research program on the basis of data on a relevant work-related health outcome—an end outcome—such as occupational hearing loss. Another somewhat less direct indicator, but defined as an end outcome in the committee’s evaluation guidance, could be evidence of changes in exposure to a workplace hazard such as excessive noise. Where application of work by NIOSH was evident, a decline in the incidence or severity of the health outcome or a reduction in a hazardous exposure might suggest a beneficial impact from NIOSH’s work, whereas no change or an increased incidence or exposure might suggest a lack of impact.

In trying to make judgments about the impact of work done by the Hearing Loss Research Program, however, the committee was unable to consider evidence for any of the four research goals that changes have occurred in end outcomes related to occupational hearing loss. As noted, there is a general lack of surveillance data on occupational hearing loss and noise exposures for U.S. workers during the past decade.

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Even if surveillance data were available, it would be necessary to understand whether changes in these outcome measures were related to the application of products from the Hearing Loss Research Program or were the result of other factors that were producing changes in the workplace or the workforce that influence levels of noise exposure or hearing loss. For example, a decline in average noise exposure among manufacturing workers might result from adoption of NIOSH recommendations for better engineering controls for noise, but it also might reflect an increase in the proportion of the manufacturing workforce engaged in work that is inherently less noisy rather than a reduction in noise levels in high-noise environments.

Data on hearing loss and noise exposures in specific workplaces or for smaller populations of workers are also scarce. A suggestive indication of a NIOSH contribution to a reduction in occupational hearing loss came from observational data from Ford Motor Company, where a model hearing loss prevention program was developed and implemented as a collaborative effort among Ford, the United Automobile Workers, and NIOSH. From 1990 through 1998, the percentage of annual audiometric tests showing an STS declined from almost 7 percent to slightly less than 4 percent (Lick, 2001; NIOSH, 2005f). However, additional information about STS levels for the years before the project and about the workplace and the workforce before and during the project period would be needed to reach conclusions about the contribution of the model hearing loss prevention program.

Few longitudinal research studies have been conducted to test the potential impact on hearing loss or noise exposure of the application of NIOSH research products either under controlled conditions or in routine work environments. Research studies can be designed to allow for the analysis of health outcomes as well as the workplace and workforce. Because occupational hearing loss typically develops over a period of years, longitudinal studies are valuable, but they are time consuming and may be expensive. Turnover in the workforce may make it difficult to maintain a stable and adequately sized study population over the course of a study. The studies also are vulnerable to conditions in the business environment, which may discourage employers from agreeing to participate or may lead them to withdraw once a study has begun.

Intermediate Outcomes

Given the lack of data on changes in the end outcomes of occupational hearing loss and noise exposure, the committee instead based much of its assessment of the impact of the NIOSH Hearing Loss Research Program on evidence that the program’s research products have been put to use beyond NIOSH in ways that have the potential to influence the workplace. Evidence of these intermediate

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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outcomes was available, in varying degrees, for all four research goals. In some instances, the committee also considered the potential for future impact from Hearing Loss Research Program publications and other program outputs that were not yet associated with intermediate outcomes.

Research Goal 1: Contribute to the Development, Implementation, and Evaluation of Effective Hearing Loss Prevention Programs

The committee saw substantial evidence that NIOSH activities related to this research goal have been adopted or adapted for use by employers, labor, audiology and occupational safety and health professionals, and government agencies. Publications and other products of the Hearing Loss Research Program that are related to Research Goal 1 have influenced health and safety regulations, the policies of professional organizations, and the education and training of hearing health professionals and members of the workforce.

Regulations The Occupational Safety and Health Act of 1970 (U.S. Congress, 1970), which called for the creation of NIOSH, authorized the agency to establish recommended occupational safety and health standards for noise control and hearing loss prevention. The NIOSH Hearing Loss Research Program has offered such recommendations most recently with Criteria for a Recommended Standard: Occupational Noise Exposure (NIOSH, 1998a). The authority to establish and enforce regulations regarding occupational safety and health standards rests with other agencies, particularly OSHA and MSHA. During the period under review, both of these regulatory agencies proposed or adopted new regulations related to occupational hearing loss, and the NIOSH Hearing Loss Research Program contributed technical assistance and public comments that reflected the 1998 recommendations. Since 2002, NIOSH has also provided technical assistance in the development of hearing loss prevention regulations to other agencies, including the Department of Transportation, Department of the Interior, Federal Aviation Administration, and California Division of Occupational Safety and Health (Cal/ OSHA).

The Hearing Loss Research program also made recommendations to OSHA about definitions of recordable occupational hearing loss and the need to record and monitor hearing loss separately from other occupational injuries and illnesses. A formal rule-making process, initiated by OSHA in 1996, resulted in the adoption of a revised criterion for recordable hearing loss and a new reporting form (the OSHA 300 log; 29 C.F.R. 1904.10) that provides for listing hearing loss separately from other occupational injuries and illnesses. These changes were implemented in 2004. The national data on occupational hearing loss that will become available

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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as a result are a welcome new resource but will not meet the need for reliable person-level data on the incidence of occupational hearing loss.

Although the NIOSH Hearing Loss Research Program’s recommendations for an 85 dBA exposure limit and a 3-dB exchange rate have not been adopted in OSHA or MSHA regulations, officials from these agencies informed the committee that NIOSH recommendations and comments are essential information for their rule-making processes. The committee concluded that failure to adopt specific NIOSH recommendations in federal regulations should not be interpreted to mean that NIOSH’s work has had no impact on those regulations. OSHA and MSHA rule making must respond to many different, and often competing, interests and perspectives on the costs and benefits of noise exposure standards. It is not possible to know whether federal regulations would offer their current level of protection for workers if contributions from the NIOSH Hearing Loss Research Program had not been available. The committee commends NIOSH for continuing to bring its recommendations to the attention of OSHA and other agencies responsible for regulating noise exposure of U.S. workers.

Also of note is that the NIOSH recommendations are consistent with and in some cases have probably influenced the noise exposure standards adopted by the Department of Defense (DoD, 2004), individual branches of the U.S. military (e.g., Department of the Army, 1998), the National Aeronautics and Space Administration (NASA, 2006), and other countries. The U.S. Army also refers to NIOSH research on ototoxicity in a fact sheet (USACHPPM, 2003) and has incorporated consideration of exposure to ototoxins in its hearing conservation program (Department of the Army, 1998). Stakeholder comments to the committee also noted that some employers have adopted the NIOSH recommendations even though they are not required by federal regulations.


Voluntary and professional standards Influential standards and guidelines concerning the measurement of noise and noise hazards are developed not only by government agencies but also by national and international standards organizations. Personnel from the Hearing Loss Research Program serve as expert members of working groups established by committees of these voluntary standard-setting organizations.

As reported by the Hearing Loss Research Program (NIOSH, 2005f), the program’s recommendations concerning impulsive noise were influential in the adoption of revisions to the international (ISO, 1990) and U.S. (ANSI, 1996) standards on noise exposure and noise-induced hearing loss. These standards have incorporated provisions that permit adding 5 dB to the measured time- and A-weighted sound level (Leq) values when impulsive noises are a substantial component of a noise exposure. However, participants in the best-practices workshop on

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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impulsive noise (convened by NIOSH and NHCA) suggested that there is no scientific evidence to justify a specific adjustment factor (Kardous et al., 2005).

Various professional organizations have incorporated NIOSH recommendations or drawn on the results of research conducted or supported by the NIOSH Hearing Loss Research Program in official statements for their members. For example, the American Academy of Audiology’s 2003 position statement “Preventing Noise-Induced Occupational Hearing Loss” (AAA, 2003) bases its description of “best practices” for hearing loss prevention programs on NIOSH (1996) guidance and its recommendations for an 85 dBA noise exposure limit and a 3-dB exchange rate on the NIOSH (1998a) criteria document. In addition, researchers from NIOSH served on the task force that developed the statement. Similarly, the American Speech–Language–Hearing Association (ASHA, 2004) drew on NIOSH publications and research from the Hearing Loss Research Program for its technical report “The Audiologist’s Role in Occupational Hearing Conservation and Hearing Loss Prevention Programs.”

The American Industrial Hygiene Association includes NIOSH recommendations from 1998 in its standard reference publication The Noise Manual (Berger et al., 2000), and the American College of Occupational and Environmental Medicine (ACOEM, 2002) cites NIOSH-sponsored research in its evidence-based position statement “Noise-Induced Hearing Loss.” Comments by stakeholders in Australia, France, and Sweden illustrated familiarity with NIOSH recommendations and publications in the international community as well.


Commercial products and product guides The committee also found evidence that work related to Research Goal 1 was being used to guide the selection and use of hearing protection devices. The Hearing Protector Device Compendium originally appeared in print form in 1976, with subsequent updates through 1994 (Franks et al., 1994). It is now available to users in an electronic form online (http://www2a.cdc.gov/hp-devices/hp_srchpg01.asp) (NIOSH, 2000a). The compendium is being used or cited by employers, unions, universities, vendors, other government agencies, and professional associations. Comments submitted to the committee from stakeholders confirm awareness of this resource in a variety of settings. Noted specifically was the usefulness of the online version of the Hearing Protector Compendium as an aid in the selection of appropriate hearing protection devices and as a tool for researchers. The impact of the compendium is also reflected in the decision by some manufacturers to voluntarily submit subject-fit data on the noise attenuation of their products. The committee strongly encourages the Hearing Loss Research Program to conduct the planned evaluation study to learn more about the effect of use of the compendium on the selection of hearing protection devices and the prevention of occupational hearing loss.

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Through a CRADA, the Hearing Loss Research Program worked with software and industry partners to contribute to the development of revised software for the management and analysis of data collected in hearing conservation programs. Transfer of this product to the workplace has been accomplished, with the software being marketed in a commercial product, the HearSāf 2000 Suite. The Hearing Loss Research Program reports that this software has been used in collaborative projects with General Motors and the United Automobile Workers.


Education and training Products of the Hearing Loss Research Program are used widely in education and training programs for occupational safety and health professionals. Preventing Occupational Hearing Loss—A Practical Guide (NIOSH, 1996) has been widely adopted for use by occupational audiology graduate courses. In addition, the Council for Accreditation in Occupational Hearing Conservation (CAOHC) covers NIOSH recommendations alongside OSHA- and MSHA-required policies in its Course Director Workshops and Professional Supervisor Courses. The Hearing Conservation Manual produced by CAOHC (Suter, 2002) includes a version of the Practical Guide’s program evaluation checklist and has an appendix that compares OSHA compliance criteria with NIOSH recommendations. This manual is used in many CAOHC-approved courses that certify occupational hearing conservationists (approximately 24,000 nurses, technicians, occupational physicians, and allied personnel) in the United States.

The Hearing Loss Research Program also provided the committee with materials and encouraging statements about the impact of training programs on the use and effectiveness of hearing protection devices for groups of carpenters and a request by the U.S. Navy to test the training with shipyard workers. Workers who received either form of training were observed to use hearing protection more than workers who had not received the training and to have improved attenuation from their hearing protectors (NIOSH, 2005f). The committee is encouraged to see the plans for additional study of the effectiveness of these training approaches for shipyard workers. Prospective studies are needed to determine if workers who receive training can maintain the improved fit and attenuation of their hearing protection and if they develop less hearing loss than untrained workers in a comparable noise environment.

The potential impact of establishing the effectiveness of these training approaches includes direct benefits not only to individual workers, but also to the evaluation of hearing loss prevention programs. If better training in use of hearing protection devices can be shown to have a strong association with the prevention of hearing loss, it may be possible to make more timely assessments of the effectiveness of hearing loss prevention programs by evaluating worker training in the use of hearing protectors and by fit-testing workers’ hearing protectors.

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Other products related to Research Goal 1 are intended for both professional and lay audiences. A hearing loss simulator developed by the Hearing Loss Research Program and designed for use on a personal computer is being used with workers and in training programs for health and safety professionals by other government agencies (including MSHA), manufacturers and vendors of hearing protection devices, universities, and professional associations. A small NIOSH study of miners and support staff (n = 89) was described as having found that exposure to the simulator produced significant increases in knowledge of hearing loss prevention and intentions to take more effective hearing conservation actions. The materials provided to the committee did not, however, describe how long the workers’ hearing conservation intentions persisted after exposure to the simulator (NIOSH, 2005f). To make a better determination of the potential impact of the hearing loss simulator among workers, the committee emphasizes the need for further studies that examine changes in the actual use of hearing protection and adherence to other practices that reduce noise exposure.

The Hearing Loss Research Program has also contributed a component on hearing loss prevention to a broader NIOSH activity to develop an occupational safety curriculum for high schools and technical training programs. The Hearing Loss Research Program reported (NIOSH, 2005f) that the curriculum was formally endorsed by the State Directors of Career Technical Education in November 2005 and will be adopted and integrated into Career Clusters programming in every state once final revisions are completed. The U.S. Job Corps is also expected to adopt the completed curriculum, and the OSHA Training Institute has already used the hearing loss prevention part of the curriculum.

NIOSH is involved in WISE EARS!­® (http://www.nidcd.nih.gov/health/wise/) (NIDCD, 2006), a national health education campaign on noise hazards and prevention of hearing loss. The Hearing Loss Research Program is a partner in the program with the NIDCD, and NIOSH aided in building a diverse coalition of more than 80 supporting organizations in the public and private sectors. NIOSH also contributed to the development, testing, and dissemination of the campaign’s messages and materials. The WISE EARS! fact sheet on work-related hearing loss is a NIOSH product and hosted on the website of the NIOSH Hearing Loss Research Program (http://www.cdc.gov/niosh/topics/noise/abouthlp/workerhl.html). Participation in WISE EARS! also may help bring the Hearing Loss Research Program and its products to the attention of the broad audience represented by the members of the coalition. Evaluation of the WISE EARS! program will help the Hearing Loss Research Program and other participants learn whether it is reaching its intended audiences or influencing hearing health outcomes.

The committee also notes the potentially subtle but valuable impact that the Hearing Loss Research Program may be having through Research Goal 1 and its

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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promotion of the term “hearing loss prevention program” as an alternative to “hearing conservation program.” Reframing the goal of these activities as prevention of hearing loss may help underscore the importance of early and continued attention to workers’ exposure to noise hazards. This change in terminology was explicitly noted in a technical report from the American Speech–Language–Hearing Association (ASHA, 2004). The committee found, however, that within NIOSH, recent HHE reports continue to refer to hearing conservation programs (e.g., Cook et al., 2001; Snyder and Nemhauser, 2003; Tubbs, 2003; Achutan et al., 2004; Methner et al., 2004), which may represent missed opportunities to reinforce the prevention message.


Dissemination of information and materials Many of the materials developed by the Hearing Loss Research Program in conjunction with work related to Research Goal 1 are available from NIOSH online. Evidence that other organizations are repackaging and distributing these materials signals endorsement of their value by others and may serve to influence wider audiences than distribution by NIOSH alone. Information from the Practical Guide (NIOSH, 1996) has been distributed through the National Safety Council publications Today’s Supervisor and Safeworker. In 2005, NIOSH began working with OSHA and NHCA to develop print and electronic materials based on the Practical Guide that can meet the needs of small businesses.

Hearing Loss Research Program staff have contributed to the dissemination of information and materials developed for this research goal through publications, including articles in peer-reviewed journals, book chapters, and papers in conference proceedings; through presentations at conferences and workshops; and by working directly with interested parties in other government agencies, industry, labor, and the occupational health and safety community. The committee was also given information about the dissemination of electronic and print materials through NIOSH. Since 2003, the electronic version of the 1998 criteria document on the NIOSH website received more than 21,000 visits, and from January 2003 to June 2005, the Practical Guide (NIOSH, 1996) received more than 13,000 visits. Since 2000, more than 1,100 organizations and individuals have requested copies of the printed versions of these documents. Nearly 10,000 print copies of the Practical Guide (NIOSH, 1996) were sent in response to these requests, and almost 15,000 copies were distributed at meetings of the NHCA, American Academy of Audiology, American Association of Occupational Health Nurses, National Safety Congress, American Industrial Hygiene Association, Ohio Safety Congress, and Allied Construction Industries and at other hearing health, service provider, and trade meetings (NIOSH, 2005f).

Although providing information to potential users is a crucial step, the com-

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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mittee cautions that publications and data on distribution of materials do not demonstrate use of the material provided. Furthermore, the Hearing Loss Research Program does not appear to have established criteria by which to judge whether the demand for its materials is appropriate or should be higher overall or in specific target audiences.


Summary assessment Information provided by the Hearing Loss Research Program and comments from many stakeholders offer strong endorsement of the contributions made to efforts to reduce occupational hearing loss through work related to Research Goal 1—contribute to the development, implementation, and evaluation of effective hearing loss prevention programs.

Nevertheless, the committee found that the Hearing Loss Research Program has not paid enough attention to evaluating the effectiveness of recommendations, training programs, and other products in terms of reducing the incidence or severity of occupational hearing loss or achieving important intermediate outcomes of sustained improvement in use of hearing protection or management of hearing loss prevention programs. Evaluation based on changes in knowledge, attitudes, or behavioral intentions is appropriate but not sufficient. Furthermore, some researchers (e.g., Clark, 1997; Dobie, 1997) have suggested that the data and analyses underlying some of the program’s recommendations should receive further scrutiny from the scientific community.

The committee is cognizant of factors that may be hindering the ability of the Hearing Loss Research Program to assess or improve the impact of its work related to Research Goal 1. Testing the effectiveness of hearing loss prevention measures requires collaboration with employers and workers, but as noted elsewhere in this report, hearing loss may be given relatively low priority in some settings. The program has worked successfully with various partners, but it has also experienced loss of access to data and study populations with staff changes at work sites.

Research Goal 2: Reduce Hearing Loss Through Interventions Targeting Personal Protective Equipment

The impact of the work of the Hearing Loss Research Program related to Research Goal 2 can be seen in substantial contributions to improving measurement of the fit and performance of hearing protection devices, with the results of that work influencing regulations and standards nationally and internationally. Work concerning hearing protection against impulsive noise and the hearing protection needs of workers with existing hearing impairments has been less extensive but is generating guidance for federal agencies.

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Regulations, recommendations, and voluntary standards Use of hearing protection devices is central to efforts to prevent noise-induced hearing loss among U.S. workers. Regulations issued by EPA (40 C.F.R. 211.206) specify that the noise attenuation offered by hearing protection devices—the Noise Reduction Rating—must be determined by a method specified in ANSI S3.19-1974 (ANSI, 1974). Work dating from the late 1970s by Hearing Loss Research Program staff and others has shown that this method of measuring noise attenuation seriously overstates the protection that most wearers receive (see NIOSH, 1998a). In particular, the NRR, which is derived from laboratory tests of devices that are fit by experimenters, overestimates noise reduction compared with reductions obtained when hearing protection devices are fit by test subjects. Hearing Loss Research Program scientists also showed that subject-fit protocols reduced inter-laboratory variability in noise reduction compared to other fit methods. One impact of this work on hearing protection devices could be said to be evident in the Hearing Loss Research Program itself. The NIOSH (1998a) recommendations for a noise standard incorporated information on the limitations of the NRR and presented alternative approaches for judging the noise attenuation obtained with hearing protection devices.

The Hearing Loss Research Program has also influenced the work of professional and voluntary standards organizations. NIOSH staff participated in an NHCA task force that recommended use of subject-fit protocols for testing hearing protection (Royster, 1995). Staff members have also served on working groups of the ANSI S12 committee, which develops voluntary standards for hearing protector testing and rating. A standard adopted in 1997 by that committee (ANSI, 1997) includes provisions for subject fit, a testing protocol, and sample sizes that are supported by citations of four publications to which NIOSH staff contributed. In 2003 and 2005, Hearing Loss Research Program staff served as U.S. delegates to related technical committees of the International Organization for Standardization and aided in developing a draft standard based on ANSI S12.6-1997 that was circulated for consideration in 2005.

The findings that the NRR overstates noise reduction have also influenced actions by U.S. regulatory agencies. The findings were a factor in the MSHA ruling in 1999 that miners’ noise exposures are to be determined without adjustments for the use of hearing protection devices (30 C.F.R. 62.110). The OSHA hearing conservation regulations, which date from the 1980s, continue to give credit for the attenuation of hearing protection devices in determining workers’ daily noise doses, but reference to newer hearing protector testing protocols in the 1997 ANSI standard have been incorporated into the OSHA (1999) Technical Manual for the agency’s compliance safety and health officers (see http://www.osha.gov/dts/osta/otm/noise/hcp/hp_labeling.html).

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Work is being done to develop revised EPA regulations on the NRR. EPA officials confirmed for the committee that Hearing Loss Research Program staff helped stimulate current consideration of revisions to the regulations and have for many years provided essential technical support to EPA concerning these regulations. The technical assistance provided to EPA has included assessing hearing protector technology and product effectiveness, developing and evaluating testing standards, and performing analyses for new rating schemes. Hearing Loss Research Program staff also aided EPA by developing, managing, and participating in the analysis of results from a six-laboratory study to compare two methods for testing hearing protector attenuation.


Technology development and transfer The work related to Research Goal 2 has achieved a degree of impact through the development of a new technology that is being used beyond NIOSH. A laboratory-based system for testing the attenuation of hearing protectors, HPDLab, was developed in collaboration with a commercial partner, Howard Leight Industries. This system meets the requirements of both ANSI S3.19 and ANSI S12.6 (ANSI, 1974, 1997). The system has been installed at the NIOSH facilities in Cincinnati and Pittsburgh and at the Howard Leight Industries laboratory in San Diego. The Hearing Loss Research Program reported that Howard Leight has participated in a NIOSH-sponsored study to test the system in multiple laboratories. The system is also being used at Howard Leight to test the firm’s products. An Army research laboratory and a commercial firm are installing the system for use in developing communication systems.

The Hearing Loss Research Program estimated that the cost of the HPDLab system is about $15,000, which is less than one-fifth the cost of systems developed commercially, and it does not require the customization necessary with a commercially developed system. Wider adoption of HPDLab may substantially reduce the cost of developing new hearing protector testing laboratories, but the committee does not have a basis for estimating the need for such facilities.

The committee is also aware that the NIOSH testing facility in Cincinnati is not certified by NVLAP. Because the Hearing Loss Research Program is an important contributor to work on fit and performance testing for hearing protection devices, the committee concluded that it is vital for the Cincinnati facility to achieve NVLAP certification. Achieving this status will help ensure the credibility of hearing protection device testing results from the NIOSH facility.

In the early 1990s, the Hearing Loss Research Program developed and patented a device, called EarTalk, to provide electronic communication capability in combination with hearing protection. One firm has licensed the technology, but more recent efforts to move the technology into commercial production have not been successful. In a 2002 test of a prototype EarTalk system at Wright-Patterson

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Air Force Base, the system did not achieve a level of speech intelligibility comparable to more expensive systems used by the military. In 2004, the Hearing Loss Research Program received a small amount of funding through NIOSH’s then-new r2p program for a transfer effort, but the program’s commercial partner ultimately withdrew, citing other competing priorities.

Although the impact of EarTalk has been limited, the committee emphasizes that it is inevitable and reasonable to expect that some worthwhile efforts may not achieve intended outcomes or may achieve them over a longer time frame than the current review. However, it is also important for the Hearing Loss Research Program to ensure that its approach to commercialization efforts is based on sound business principles and is adequately supported.


Needs of workers with hearing impairment Workers who have existing sensorineural hearing impairments need to protect their remaining hearing ability and may need protection that is compatible with the use of hearing aids. Laboratory and field testing is being done to develop a protocol to guide the selection of hearing protection devices that maximize speech intelligibility for hearing-impaired workers while providing appropriate noise exposure reduction. The Hearing Loss Research Program reported that it has used the early results of this work to offer consultations and presentations to provide guidance to OSHA, MSHA, employers, and professional organizations on managing the hearing protection needs of employees with hearing impairments.


Health Hazard Evaluations Hearing Loss Research Program staff participate in NIOSH HHEs that investigate potential hazards to hearing. These investigations present opportunities to convey the program’s research findings and recommendations on best practices to specific employers and groups of workers. HHE investigations of firearms training facilities for law enforcement personnel (Tubbs and Murphy, 2003; Harney et al., 2005) included consideration of hearing protection against exposures to impulsive noise, an issue being addressed under Research Goal 2. The Hearing Loss Research Program reported to the committee that the U.S. Citizenship and Immigration Service (formerly the Immigration and Naturalization Service) of the Department of Homeland Security and Oak Ridge National Laboratory in the Department of Energy are implementing NIOSH recommendations on selection and use of hearing protection devices for personnel exposed to hazardous impulsive noise.


Summary assessment In its review of the work related to Research Goal 2, the committee found that the Hearing Loss Research Program has made important contributions to increasing knowledge about the real-world performance of hear-

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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ing protection devices, improving the methods and tools for assessing hearing protector attenuation, and encouraging relevant agencies and organizations to modify noise regulations and other guidance concerning hearing protector attenuation. The ability of the Hearing Loss Research Program to help constituents in the field of hearing protection device regulation reach consensus around ANSI S12.6-1997 has been especially noteworthy. The committee suspects that participation by Hearing Loss Research Program staff not only in intramural research but also in collaborations with other agencies and with academic scientists, hearing protector manufacturers, employers, and workers adds to the impact of the program in ways that are difficult to trace.

Work related to Research Goal 2 that is still maturing has the potential to have substantial impact on hearing loss prevention practices and the health of noise-exposed workers. The committee notes in particular the efforts to develop practical methods of testing hearing protector fit in the workplace and to characterize the effectiveness of hearing protection devices against impulsive noise.

Research Goal 3: Develop Engineering Controls to Reduce Noise Exposure

The impact of the work of the Hearing Loss Research Program related to Research Goal 3 is evident primarily in areas related to mining, particularly the development of quieter equipment for underground coal mining and contributions to MSHA’s regulatory activities. Although some noise control developments related to mining could be applied in the construction industry, the Hearing Loss Research Program’s work related to Research Goal 3 appears to have had little impact in other industrial sectors to date.


Technology development and transfer Work related to Research Goal 3 has resulted in the development of modifications to two products that are now being manufactured and used in coal mines. To accomplish the development and application of these products, the Hearing Loss Research Program participated in a collaborative effort with labor, mine operators, equipment manufacturers, and MSHA.

One product is a chain conveyor with coated flight bars for continuous mining machines. MSHA identified this product as a “promising” noise control technology in a 2004 Program Information Bulletin (McKinney et al., 2004). The chain conveyor with coated flight bars that the Hearing Loss Research Program helped develop is currently being manufactured and sold by Joy Manufacturing, Inc. This manufacturer produces more than 80 percent of the continuous mining machines in the United States, which suggests that the coated flight bar technology for chain conveyors is accessible to many coal mine operators. The Hearing Loss Research

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Program reported that the technology is in use at two coal mines, but no data were provided on any measured changes in noise exposures of workers in those mines.

The other noise control technology cited by the Hearing Loss Research Program is the application of wet or mist drilling systems to roof bolting machines that are used in underground coal mines. Roof bolting machines equipped for wet drilling are currently available from J.H. Fletcher and Co., the leading U.S. manufacturer of roof bolting machines. Hearing Loss Research Program researchers verified the effectiveness of a mist system sold as a retrofit for roof bolting machines. MSHA classified wet drilling (where compatible with the geology and mining method) as a “technologically achievable” noise control and mist drilling as a promising control (McKinney et al., 2004).

MSHA defines a technologically achievable noise control as one that contributes (alone or in combination with other controls) to a 3-dBA reduction in noise exposure (McKinney et al., 2004). The committee was informed that wet and mist drilling systems are currently in use in six mines (Matetic, 2006). Any change in miners’ noise exposures in these mines was not described in the materials provided to the committee.


Regulations and standards MSHA officials (Seiler and Pon, 2006) informed the committee that NIOSH provides essential research support to MSHA’s regulatory and enforcement activities. Specific contributions by NIOSH related to engineering controls have included providing consultation and support during the rule-making process for the 1999 MSHA noise standard (30 C.F.R. Part 62) on the hierarchy of hazard controls and the feasibility of engineering noise controls. Also noted were NIOSH contributions to the MSHA policy statement “Technologically Achievable, Administratively Achievable, and Promising Noise Controls” (McKinney et al., 2004).

With the MSHA noise standard’s emphasis on engineering controls to meet noise exposure limits, there is a strong basis for a linkage between MSHA and work related to the Hearing Loss Research Program’s Research Goal 3. By contrast, the Hearing Loss Research Program’s work on engineering controls appears to have a weaker connection to OSHA. The OSHA noise standard dates from the early 1980s and, while stating a preference for engineering solutions to excess noise exposure, allows for reliance on hearing protection devices to meet exposure limits. Since the mid-1990s, OSHA has taken some preliminary steps toward additional regulation of noise exposure and hearing conservation in the construction industry. An OSHA representative (Maddux, 2006) reported that the Hearing Loss Research Program is supporting this early regulatory work by providing information on noise levels of equipment at construction sites that OSHA will use in refining risk assessments. The committee noted, however, that only one NIOSH publication on noise con-

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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trol, which dates from 1978, is included in the references on the “Controls” page of the Noise and Hearing Conservation section of the OSHA website (OSHA, 2005; see http://www.osha.gov/SLTC/noisehearingconservation/hazards_solutions.html).

Work related to Research Goal 3 also appears to be contributing to the development of voluntary standards on construction noise. The database developed by the Hearing Loss Research Program on sound levels generated by powered hand tools (see http://www.cdc.gov/niosh/topics/noise/workplacesolutions/toolsDatabase.html) was used as an information resource by drafters of the proposed ANSI S10.46 construction noise standard.


Powered hand tool database The powered hand tool database project has the potential to provide information that could assist employers, workers, and the public in the selection of quiet equipment. During July and August 2005, the website for the powered tool database received 633 visits, but it is not possible to determine whether or how these visitors used the information. This work may not be well recognized by the power tool industry. The website for the Power Tool Institute, whose members include major manufacturers of powered hand tools and whose mission includes promoting safe use of these tools, includes no references to NIOSH or the powered tool database (see http://www.powertoolinstitute.com/links.html).

The committee is concerned that the testing of the power tools was done in a university facility that lacks NVLAP accreditation. The small size of the testing laboratory limited the size of tools that could be tested, and the facility’s lack of NVLAP accreditation may undermine the credibility of test results. In particular, relying on a group of unrelated contractors, assisted by students, to conduct tests in an unaccredited facility for what appears to be intended to serve as a national reference database struck the committee as inappropriate and offering little basis for seeking to enhance the impact of the database.

The committee is also concerned that the searchable version of the database does not provide users with complete information about the conditions under which tools were tested (under load or unloaded) and that therefore the information on sound levels produced may be misleading. Without knowing whether the reported sound pressure levels are for loaded or unloaded operating conditions, users of the database may make inaccurate calculations of noise doses or hearing protection device requirements. This situation suggests the possibility that the database in its original form could have an adverse impact on hearing loss prevention. In discussions with committee members, Hearing Loss Research Program staff agreed that the operating condition under which the tools were tested should be added as a field in the searchable online database. The committee notes that the database had not been updated at the time this report was being completed.

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Training Despite its concern about the database of sound levels of powered hand tools, the committee recognizes that development of the database provided an opportunity for the Hearing Loss Research Program to collaborate with the University of Cincinnati and to have an impact through expanding training resources and experience for researchers. The university’s acoustics laboratory was upgraded, and a small number of engineering researchers gained training and hands-on experience in sound power level testing.

In a separate activity, engineering students at five universities participated in projects to identify noise sources and develop new noise controls or apply existing controls to reduce overall noise emissions from powered tools. Two papers produced as a result of these projects were recognized by the Institute of Noise Control Engineering as “student paper of the year” in 2003 and 2004.

The Hearing Loss Research Program also reported that enrollment in a University of Cincinnati acoustics class had increased by 10 to 15 students since the program’s partnership with the university. The committee cautions that increased enrollment in a single class at a single university constitutes a very modest impact for the Hearing Loss Research Program.


Health Hazard Evaluations HHEs are generally a response to concerns about hazards in a specific workplace and therefore have a limited potential for impact. They do not provide a basis for planned efforts to address noise control needs, but in a few instances (e.g., Harney et al., 2005), HHE reports have presented an opportunity to identify ways in which employers can reduce noise generation and transmission in a given workplace. Because NIOSH does not routinely revisit HHE sites, it is not possible to determine the extent to which suggested noise control actions were implemented.


Summary assessment For Research Goal 3, the committee found that the Hearing Loss Research Program is engaged in a narrow set of activities on engineering noise controls and that these activities have had a limited impact and may have limited prospects for future impact. With the larger share of the work related to Research Goal 3 taking place at the Pittsburgh Research Laboratory, the focus is on engineering noise controls for mining. Mining equipment incorporating the results of two projects pursued by Hearing Loss Research Program staff and their collaborators outside NIOSH is being produced by manufacturers and is in use in at least a small number of underground coal mines. The program has also made contributions to efforts by MSHA to identify technologically feasible and promising noise controls for use in mining.

The Hearing Loss Research Program’s work on engineering noise controls

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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appears to have had little focus or impact on industrial sectors beyond mining. Only 2 of the 38 stakeholders who submitted comments to the committee cited engineering controls in their remarks about the program’s work, outputs, or impact. One of them specifically noted the apparently low impact of the work, attributing this to lack of resources. Given the focus on mining in Pittsburgh, it seems likely that engineering noise control work related to other industries would be done through the program’s Cincinnati facility, where staffing, facilities, funding, and leadership for such work have been minimal.

Development of the database on noise emission levels of powered hand tools has the potential to contribute information to users of these tools, but it makes no contribution to the development of engineering noise controls for them, either in the design of the products or in their use. The committee is concerned about the Hearing Loss Research Program’s approach to creating the powered hand tool database. The work for what appears to be intended as a national reference database was done in an unaccredited facility without the benefit of a strong quality control program or organizational structure governing the operations of the laboratory. In addition, the database, as originally published, is incomplete because it lacks information about the operating conditions under which the tools were tested.

The student projects to design noise control solutions for powered tools provided an opportunity for a few students to be introduced to noise control engineering. However, this training experience represents little near-term contribution on the part of the Hearing Loss Research Program to the development of robust and manufacturable noise control solutions for these widely used tools.

The committee is aware that external factors have had some bearing on the Hearing Loss Research Program’s noise control engineering efforts. With the promulgation of the MSHA noise standard in 1999, engineering noise control gained primacy over hearing protection devices for preventing occupational hearing loss in mine workers. This change prompted increased interest in the mining community in collaborating to develop engineering controls for mining equipment noise. The emphasis on mining in the Hearing Loss Research Program’s work on engineering noise controls is reinforced by the availability of funding within NIOSH for work targeted specifically to mining safety and health.

By contrast with the MSHA standard, the OSHA noise standard allows for greater reliance on hearing protection devices to meet noise exposure limits. As a result, in industries other than mining, the regulatory and economic incentives have been insufficient to stimulate much interest in developing engineering noise controls. OSHA representatives confirmed to the committee that the lack of regulatory pressure for engineering noise controls in the manufacturing and construction sectors, which are under OSHA’s jurisdiction, helps make it difficult for the

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Hearing Loss Research Program to successfully transfer engineering controls, some of which may originate in work related to mining, to a broader range of workplaces and equipment manufacturers.

Research Goal 4: Improve Understanding of Occupational Hearing Loss Through Surveillance and Investigation of Risk Factors

The Hearing Loss Research Program’s work related to Research Goal 4 has been directed in large part to data gathering, epidemiologic studies, and studies using laboratory animals to investigate the causative mechanisms of hearing loss. Over the past decade an increasing proportion of the work related to this research goal has been performed extramurally. Scientific advances typically accrue slowly from work of this sort, especially from studies in laboratory animals. Even with a high degree of success in determining the biological mechanisms through which hearing loss arises, contributions to the desired end outcomes of reductions in the incidence or severity of occupational hearing loss are likely to occur through processes that may be long, unpredictable, and not under the control of NIOSH. In assessing the impact of work related to this research goal, the committee considered contributions to the knowledge base to be important intermediate outcomes.


Scientific knowledge Through both intramural and extramural work, the Hearing Loss Research Program has produced new knowledge about the complex factors that may contribute to occupational hearing loss. The program has conducted or supported novel studies to document the potential ototoxic effects of chemical exposures in the workplace and the interactive effects of chemical ototoxins and noise, to assess the differential effects of impulsive and continuous noise, and to investigate the genetic factors contributing to susceptibility to noise-induced hearing loss using mouse models. The NIOSH evidence package noted that various papers reporting on this research are being cited in the research literature, and numerous comments received from stakeholders acknowledged the program’s contribution to scientific knowledge about hearing. Although the direct impact of these studies cannot be measured in terms of “ears saved,” the studies are part of long-term endeavors that contribute to improvements in human hearing health.


Surveillance Surveillance is a major focus for this research goal, and the Hearing Loss Research Program has contributed to some advances. During the period under review, the program worked with OSHA to establish new procedures for reporting occupational injuries and illnesses that provide for identifying recordable cases of hearing loss separately from other conditions. The reporting change was implemented in 2004. The new OSHA reporting requirements for hearing loss

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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are enabling BLS to provide annual data on the number of cases of recordable hearing loss in various industrial sectors. This is a welcome step toward documenting, on a national level, the magnitude of the hearing health problem among workers. The data will also provide a means to monitor patterns of workers’ hearing losses over time.

Previously, data on occupational hearing loss were being reported on a regular basis only by the State of Michigan (see Rosenman and Panasuk, 2004; see also NIOSH, 2004). Beginning in 1992, the Hearing Loss Research Program provided technical and financial support to Michigan to establish a case ascertainment system for noise-induced hearing loss through the Sentinel Event Notification System for Occupational Risks (SENSOR). The Michigan program includes referral assistance for companies that do not have their own hearing conservation programs. The Michigan data are a mix of reports of standard threshold shifts and hearing tests showing thresholds that meet specific criteria; the data come from employers’ hearing conservation programs and reports from audiologists and otolaryngologists.

The newly available national data and the Michigan data are welcome information, but the epidemiologic value of both datasets is somewhat diminished by their case definitions and denominators. These data collection systems do not make use of traditional epidemiologic definitions of hearing loss and methods to capture person-level data to measure the true incidence of hearing loss in workers. Another concern is that the proportion of hearing loss cases that are identified may vary among industries. The committee commends the Hearing Loss Research Program for its success in raising awareness of the need to document the occurrence of hearing loss in workers, but the committee also emphasizes that it is essential for the program to have epidemiologic expertise fully integrated into its work on surveillance to help maximize the utility of the data collected.


Standards and guidelines The Hearing Loss Research Program’s work on ototoxic chemicals is contributing to wider attention to potential ototoxic hazards of workplace exposure to certain chemicals, alone or in combination with noise. As noted in conjunction with Research Goal 1, the U.S. Army refers to NIOSH research on ototoxicity in a fact sheet (USACHPPM, 2003) and has incorporated consideration of exposure to ototoxins in its hearing conservation program (Department of the Army, 1998). The Hearing Loss Research Program has also worked with various organizations to help prepare guidelines on best practices related to ototoxic substances. For example, the American Conference of Governmental Industrial Hygienists (ACGIH) notes ototoxic chemical hazards in the noise section of its Threshold Limit Values and Biological Exposure Indices (ACGIH, 2003). Occupational ototoxic hazards are addressed outside the United States in worker

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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compensation legislation in Australia and Brazil and in worker health and safety standards, such as a 2003 directive issued by the European Parliament and the Council of the European Union (2003). Explicit links to NIOSH and the Hearing Loss Research Program are not necessarily evident, but with the extensive publication record of program researchers, it seems reasonable to credit them with some influence on these developments.


Summary assessment The Hearing Loss Research Program cannot be expected to demonstrate the impact of the work conducted as part of Research Goal 4 on the basis of outcomes such as reductions in the incidence rate, numbers of cases, or severity of occupational hearing loss. The committee does, however, consider contributions that the work makes to the knowledge base on occupational hearing loss to be important intermediate outcomes. These contributions are essential steps along the pathway to effective public policies and improved public health outcomes.

The program’s work on ototoxicity is widely cited by other researchers and is reflected in the hearing conservation policies of some organizations. Support for OSHA’s implementation in 2004 of separate reporting of recordable occupational hearing loss has contributed to generating at least a minimal form of national surveillance data, which NIOSH and other researchers will be able to use to learn more about contemporary patterns of occupational hearing loss. The committee considers it very likely that application of knowledge generated by the program about the effects of chemical exposures and impulsive noise on hearing will lead to greater awareness of these effects and to improved worker health and safety in the future. For the program’s work on genetic and age-related aspects of hearing loss, however, some contribution to basic knowledge regarding hearing health is possible, but work being done in these areas seems unlikely to contribute to knowledge regarding noise exposure and hearing loss among workers.

OVERALL EVALUATION OF THE IMPACT OF THE HEARING LOSS RESEARCH PROGRAM

As it did with its assessment of the relevance of the Hearing Loss Research Program, the committee’s evaluation of impact reflects consideration of the program as a whole as well as its components, as represented by the four research goals. It was not possible to assess the program’s impact on the basis of changes in the incidence or severity of occupational hearing loss or in noise exposure experienced by workers. Indeed, the lack of such data on these end outcomes is one of the major challenges of the field. The committee turned to what it considered intermediate outcomes to make its assessment of impact.

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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In making its assessment of the impact of the Hearing Loss Research Program, the committee considered how to combine the varied evidence of the program’s impact. The conclusion reached was that the committee’s rating should rest primarily on the degree to which evidence of positive impact could be observed. Areas of limited impact were not allowed to detract on an equally weighted basis from more successful efforts.

The committee found that the Hearing Loss Research Program has made contributions through publication of findings from intra- and extramural research in the peer-reviewed scientific literature, collaborative development of technologies for application in the workplace, collection and publication of resource materials for technical and lay audiences, development and delivery of educational programs, participation in the development of various national and international voluntary standards concerning noise and hearing loss, development of recommendations on noise exposure limits and hearing loss prevention practices, and consultation and collaboration with regulatory agencies.

It is clear to the committee that many of the program’s work products have been adapted or adopted for use by business, labor, and occupational health professionals. Examples include adoption by the U.S. Army of the 1998 NIOSH recommendations for an 85 dBA 8-hour time-weighted average as constituting a 100 percent daily noise dose and use of a 3-dB exchange rate for determining trade-offs in the level and duration of noise exposure, and acceptance of the NIOSH recommendation for a 3-dB exchange rate and an 85-dB exposure limit by major professional organizations. Stakeholders reported widespread use of Preventing Occupational Hearing Loss—A Practical Guide (NIOSH, 1996) and the hearing protector compendium.

The committee found that the Hearing Loss Research Program has made important contributions to increasing knowledge about the real-world performance of hearing protection devices, improving the methods and tools for assessing hearing protector attenuation, and encouraging relevant agencies and organizations to modify regulations and other guidance concerning hearing protector attenuation.

The program provided support for establishing the feasibility of MSHA’s listed engineering noise controls, contributed to rule making requiring noise control as the primary focus of occupational hearing loss prevention in mines, and contributed to international standards and heightened awareness by some U.S. organizations of the ototoxicity of several chemicals used widely in industry. In addition, the program encouraged the implementation by OSHA of new procedures for reporting occupational hearing loss on the OSHA 300 log, which will provide some basis for monitoring national patterns of workplace hearing loss. The program’s participation in health hazard evaluations presents an opportunity to inform workers and employers about workplace noise hazards and to make rec-

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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ommendations for corrective steps that are based on the program’s work in various areas, but in practice, the impact of these site-specific reviews is likely to be limited.

The committee sees the program as being, despite its small size, a unique and essential resource in efforts to protect workers’ hearing. With no authority to establish or enforce regulations concerning workplace noise exposure and hearing conservation, some of the program’s impact must be achieved through activities such as consultation with regulatory agencies, principally OSHA, MSHA, and EPA, and with employers, workers, equipment manufacturers, and occupational safety and health professionals. The impact of contributions in the form of formal and informal consultation, advice, and recommendations may be difficult to document but should not be discounted.

Nevertheless, the committee found that the Hearing Loss Research Program has not given sufficient attention to consideration of performance criteria related to intermediate or end outcomes. Developing such criteria could aid the program in identifying desired forms of impact, targeting efforts toward achieving those outcomes, and assessing progress. A related concern is the need for more attention to evaluation of the effectiveness of the program’s activities and the view that some of the evaluation efforts that are being made could be more useful if they were based on end outcomes, such as reducing the incidence or severity of occupational hearing loss, or on achieving important intermediate outcomes, such as sustained improvement in the use of hearing protection or in the management of hearing loss prevention programs. Evaluation based on changes in knowledge, attitudes, or behavioral intentions is not sufficient.

The committee is also concerned that too little attention has been given to developing data on the incidence and severity of occupational hearing loss and the levels and extent of noise exposure among workers. Such data are essential for determining the most meaningful impacts of the work of the Hearing Loss Research Program. Developing and maintaining surveillance systems present substantial challenges, but well-designed longitudinal research studies could provide not only valuable descriptive information on noise exposure and hearing loss but also the opportunity to test the effectiveness of recommended hearing loss prevention measures.

The program may also be missing the opportunity to help build a stronger scientific basis for aspects of occupational hearing loss prevention. With a few notable exceptions, researchers in the Hearing Loss Research Program have made only limited contributions to the peer-reviewed research literature. Presentations and other kinds of publications are important contributions, but they cannot take the place of formal documentation of research results. Timely publication of research results and conference proceedings helps keep the wider scientific community informed about the program’s work and encourages other researchers to test

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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and build on findings from the NIOSH program. Relying on unpublished analyses as a foundation for important policy recommendations may, in the long run, weaken the credibility of those recommendations.

The program’s narrow set of activities in engineering noise controls appears to have had a limited impact, mostly in mining, and may have limited prospects for future impact, especially in other industrial sectors. Development of the database on noise emission levels of powered hand tools is a source of concern because of the lack of rigor in the laboratory operations and the lack of attention to the content and performance of the online database. The committee also considers the student projects to design noise controls as offering little prospect for impact on noise exposures. Furthermore, work regarding genetic and age-related aspects of hearing loss is likely to make some contribution to basic knowledge in these areas, but will not readily contribute to knowledge regarding noise exposure and hearing loss among workers.

On the basis of its review, the committee has assigned the NIOSH Hearing Loss Research Program a score of 4 for impact, notwithstanding significant short-comings in some aspects of the program. This score reflects a judgment that the Hearing Loss Research Program has made a moderate contribution on the basis of well-accepted intermediate outcomes, has generated important new knowledge, and is engaged in transfer activities (see Box 2-3). This score reflects the committee’s assessment that the program has had identifiable and worthwhile impact that should not be discounted because of lesser degrees of impact from some aspects of the program.

BOX 2-3

Scale for Rating Program Impact

5

=

Research program has made a major contribution to worker health and safety on the basis of end outcomes or well-accepted intermediate outcomes.

4

=

Research program has made a moderate contribution on the basis of end outcomes or well-accepted intermediate outcomes; research program generated important new knowledge and is engaged in transfer activities, but well-accepted intermediate outcomes or end outcomes have not been documented.

3

=

Research program activities or outputs are going on and are likely to produce improvements in worker health and safety (with explanation of why not rated higher).

2

=

Research program activities or outputs are going on and may result in new knowledge or technology, but only limited application is expected.

1

=

Research activities and outputs are NOT likely to have any application.

NA

=

Impact cannot be assessed; program is not mature enough.

Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
×

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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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×

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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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×
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Suggested Citation:"2 Evaluation of the Hearing Loss Research Program." Institute of Medicine and National Research Council. 2006. Hearing Loss Research at NIOSH: Reviews of Research Programs of the National Institute for Occupational Safety and Health. Washington, DC: The National Academies Press. doi: 10.17226/11721.
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Next: 3 Identifying Emerging Issues and Research Areas in Occupational Hearing Loss Prevention »
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The National Institute for Occupational Safety and Health (NIOSH) was established by the Occupational Safety and Health Act of 1970 (U.S. Congress, 1970). Today the agency is part of the Centers for Disease Control and Prevention of the U.S. Department of Health and Human Services. NIOSH is charged with the responsibility to "conduct . . . research, experiments, and demonstrations relating to occupational safety and health" and to develop "innovative methods, techniques, and approaches for dealing with [those] problems" (U.S. Congress, 1970). Its research targets include identifying criteria for use in setting worker exposure standards and exploring new problems that may arise in the workplace. Prevention of occupational hearing loss has been part of the NIOSH research portfolio from the time the agency was established. A principal cause of occupational hearing loss is the cumulative effect of years of exposure to hazardous noise. Exposure to certain chemicals with or without concomitant noise exposure may also contribute to occupational hearing loss. Hearing loss may impede communication in the workplace and contribute to safety hazards. Occupationally acquired hearing loss may also have an adverse effect on workers' lives beyond the workplace. No medical means are currently available to prevent or reverse it, although hearing aids are widely used and research on other treatments is ongoing. Occupational hearing loss is a serious concern, although the number of workers affected is uncertain.

In September 2004, NIOSH requested that the National Academies conduct reviews of as many as 15 NIOSH programs with respect to the impact and relevance of their work in reducing workplace injury and illness and to identify future directions that their work might take. The Hearing Loss Research Program was selected by NIOSH as one of the first two programs to be reviewed.

Hearing Loss Research at NIOSH examines the following issues for the Hearing Loss Research Program: (1) Progress in reducing workplace illness and injuries through occupational safety and health research, assessed on the basis of an analysis of relevant data about workplace illnesses and injuries and an evaluation of the effect that NIOSH research has had in reducing illness and injuries, (2) Progress in targeting new research to the areas of occupational safety and health most relevant to future improvements in workplace protection, and (3) Significant emerging research areas that appear especially important in terms of their relevance to the mission of NIOSH.

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