6
Ensuring Adequate Diagnosis and Treatment: Access, Capacity, and Technology Development

CHAPTER SUMMARY Millions of individuals suffering from sleep disorders remain undiagnosed and untreated. Most American communities do not have adequate health care resources to meet the clinical demands. Further, the current diagnostic and therapeutic capacity is not sufficient for the present demand, let alone the predicted increase in demand arising from the proposed public education campaign. Thus, additional technology development is required. Based on estimates of the prevalence of sleep disorders, millions of individuals are undiagnosed and untreated. As awareness increases, greater investment in the development and validation of new diagnostic and therapeutic technologies will be required to meet the anticipated demand. Numerous technological advances have enhanced the feasibility of portable diagnosis and treatment, but they have not been fully evaluated and validated. Therefore, the committee urges the evaluation and validation of existing diagnostic and therapeutic technologies, as well as the development of new technologies.



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6 Ensuring Adequate Diagnosis and Treatment: Access, Capacity, and Technology Development CHAPTER SUMMARY Millions of individuals suffering from sleep disorders remain undiagnosed and untreated. Most American communities do not have adequate health care resources to meet the clinical demands. Further, the current diagnostic and therapeu- tic capacity is not sufficient for the present demand, let alone the predicted increase in demand arising from the proposed public edu- cation campaign. Thus, additional technology development is re- quired. Based on estimates of the prevalence of sleep disorders, millions of individuals are undiagnosed and untreated. As aware- ness increases, greater investment in the development and valida- tion of new diagnostic and therapeutic technologies will be required to meet the anticipated demand. Numerous technological advances have enhanced the feasibility of portable diagnosis and treatment, but they have not been fully evaluated and validated. Therefore, the committee urges the evaluation and validation of existing diag- nostic and therapeutic technologies, as well as the development of new technologies. 217

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218 SLEEP DISORDERS AND SLEEP DEPRIVATION Increased awareness among the general public and health care practi- tioners will present numerous challenges to existing health care providers and researchers who are already stretched too thin. Therefore, as described in the following sections, development and improved capacity through tech- nology development is required. An increased recognition of sleep disorders has resulted in an increase in demand. In a 3-year period over the late 1990s, demand for a sleep test doubled in the United States (Pack and Gurubhagavatula, 1999). In France the number of patients diagnosed and receiving continuous positive airway pressure (CPAP) treatment is annually increasing by 20 percent (Gagnadoux et al., 2002). Demand has been accompanied by improved patient access to physicians and other clinicians trained in sleep medicine and to facilities where clinical sleep tests, polysomnograms, can be performed. There are currently an estimated 1,292 sleep centers or laboratories in the United States, 39 percent of which were accredited by the American Academy of Sleep Medicine (AASM) (Tachibana et al., 2005). However, resources have not kept up with demand. For example, 80 to 90 percent of obstructive sleep apnea (OSA) cases remain undiagnosed and untreated, which increases the burden of this disorder (Kapur et al., 2002). Narcolepsy, too, is infre- quently detected (Singh et al., 2005), but precise rates of under diagnosis are not available because this condition is less common. Similarly, there is poor recognition and treatment of insomnia (Benca, 2005), as well as poor communication between patient and physician. Thus, even with a growth in resources, this issue is of significant importance to the millions of indi- viduals suffering from sleep disorders. DEVELOPING PORTABLE DIAGNOSTIC TOOLS Polysomnography, the “gold standard” procedure for the diagnosis of most sleep disorders, is not readily available for everyone who needs it. These procedures employ simultaneous monitoring of numerous physiologi- cal parameters including brain wave activity, eye movements, muscle activ- ity (chin and legs), heart rate, body position, and respiratory variables, in- cluding oxygen saturation. The test is typically performed overnight in a sleep laboratory with a technician in attendance, requiring an individual to sleep in the laboratory. Thus, this procedure necessitates facilities that ac- commodate overnight testing (beds and monitoring areas), highly sophisti- cated equipment, trained staff who are willing to work night shifts, and physicians trained in sleep medicine. Although there may currently be cost-effective ways to manage sleep disorder, the capacity does not currently exist to diagnose and treat all individuals. Most American communities do not have adequate health care resources to meet the clinical demands of treating the large number of

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219 ENSURING ADEQUATE DIAGNOSIS AND TREATMENT patients with sleep disorders (Banno and Kryger, 2004; Tachibana et al., 2005). In many health care systems and communities, waiting lists may be as long as 10 weeks (Rodsutti et al., 2004), with even longer waiting times in certain systems such as Veterans Affairs Medical Centers (Sharafkhaneh et al., 2004). Although this is not a problem that is unique to the field, long wait lists cause significant delays in diagnosing and treating individuals (Banno and Kryger, 2004). This is of particular concern for individuals with sleep disorders that lead to increased chance of injury. For example, undiagnosed severe OSA can lead to death or serious harm of self or others due to crashes (George, 2001). Further, long wait times contribute to high no-show rates that in turn increases the length of the wait-lists (Callahan and Redmon, 1987; Olivares, 1990). This also may decrease market share (Christl, 1973; Antle and Reid, 1988). It has been estimated that sleep apnea alone, a diagnosis that necessitates polysomnography to meet current criteria set out by third-party payers, annually requires at least 2,310 polysomnograms per 100,000 population to address the demand for diag- nosis and treatment (Flemons et al., 2004). However, on average, only 427 polysomnograms per 100,000 population are performed each year in the United States, a level far below the need. In fact, 32 states annually perform less than 500 polysomnograms (Tachibana et al., 2005). Only Maryland annually performs more than 1,000. This large geographic variability in levels of sleep services is not explained by Medicare reimbursement rates, race, or distribution of OSA risk factors in these areas (Tachibana et al., 2005). Further, such geographical variability suggests the need for more standardized approaches for diagnosis and disease management. Limitations in providing overnight diagnostic sleep laboratory services are attributed to a number of factors. Direct costs associated with having a polysomnogram performed (Chapter 4) are high. In addition, there are high expenses to sleep laboratories, including costs related to the initial invest- ment in equipment (hardware and software) and information technology needed to manage large amounts of digital data. There are considerable personnel costs related to dedicating one to two trained technicians to each patient for a 10- to 12-hour period (for orientation, hookup, and minute- by-minute monitoring) and for scoring of studies (2 to 3 hours per study), overhead for space (which traditionally has used in-patient hospital space and more recently has used space in upscale hotels that contract with health care organizations to provide rooms or floors that serve as “community- based sleep laboratories”), and costs related to consumable supplies used for monitoring. Most insurers require sleep laboratories to be supervised by physicians or other clinicians certified by the American Academy of Sleep Medicine. In addition, many patients are reluctant to undergo somewhat intrusive monitoring and to spend one or more nights away from home. The latter is of special concern to individuals with home care (of their chil-

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220 SLEEP DISORDERS AND SLEEP DEPRIVATION dren or parents) responsibilities. These factors have contributed to an inter- est in developing portable, and perhaps simpler, less costly and less intru- sive devices that can be used in a patient’s own home, with the goals of improving access and decreasing the cost of sleep studies. The Potential of Developing Portable Sleep Monitoring Numerous technological advances have enhanced the feasibility of por- table monitoring. These include miniaturization of recording components, efficiencies of digital data storage, remote monitoring capabilities (allowing centrally based technicians to monitor signals at home via wireless or mo- dem communications), and development of new physiological sensors. Ad- vances have been such that essentially the same data that are collected using full polysomnography in the laboratory can be collected in the home with monitors that weigh less than 300 grams. Large-scale epidemiological stud- ies have demonstrated the feasibility of such multichannel recordings done in children and in middle-aged and elderly individuals (Goodwin et al., 2003; Redline et al., 1998). Recent experience in a community sample of almost 3,000 older men, a large percentage of whom had OSA and periodic limb movements, indicates that this approach can yield high quality data in 97 percent of studies performed (personal communication, S. Redline, Case Western Reserve University School of Medicine, December 15, 2005). The improvement in the high quality of data in this study compared to previous studies is largely due to technological advances. A study comparing the quality of data obtained from an in-home to an in-laboratory study demon- strates comparable quality and evidence of slightly less stage 1 sleep (i.e., lighter sleep) in the home, suggesting that patients may sleep better and have more representative sleep at home (Iber et al., 2004). The apnea- hypopnea index (AHI) determined using the two methods were highly cor- related; however, a Bland Altman plot showed that at lower AHIs, the AHI tended to be lower in the laboratory than at home, and at higher AHIs, the AHI was higher in the laboratory than home. The latter phenomenon was thought to relate to positional differences in apnea severity, with severely affected patients probably spending more time on their back when sleeping in the typical hospital bed than when studied at home. However, although recent studies suggest low failure rates, there may be significant differences in the failure rates of unattended monitoring in less controlled settings. Thus examination of the efficacy of such technologies should be performed in less controlled settings, as may occur in clinical practice. Despite the promise of this technology, such comprehensive monitor- ing, even at home, is probably as burdensome to patients as when per- formed in the laboratory, requires a technician to travel to the patient’s

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221 ENSURING ADEQUATE DIAGNOSIS AND TREATMENT home to set up and retrieve the units, and has a higher failure rate due to all the vagaries of using many sensors in an unattended manner. Failure rates between 5 to 20 percent have been reported for ambulatory diagnostic devices (Redline et al., 1998; Whitney et al., 1998; Fry et al., 1998; Mykytyn et al., 1999; Portier et al., 2000); however, since these reports were released there have been many technological improvements. A formal cost-benefit analysis of 12 to 14 multichannel in-home monitoring compared to in- laboratory monitoring has not been performed. Thus, there is interest in use of simpler technology with sufficient predictive value to be used in decision making. Technological advances also have led to the incorporation and packag- ing of various groups of sensors, many novel, designed to provide simpler means for quantifying airflow limitation or breathing effort, oxygen de- saturation, snoring sounds, movement, heart rate, blood pressure, and vas- cular tone variability. Several of these devices are designed to primarily provide estimates of sleep and wake time over 24-hour periods, such as wrist actigraphs (i.e., a movement detector coupled with software that uses movement patterns to provide estimated sleep and wake times) (Ancoli-Israel et al., 1997). These are used more often in research than in clinical settings, although clinically they have been used to enhance evaluation of sleep-wake disorders. These devices provide estimates of sleep time that correlate moderately well to polysomnography-based estimates; however, in certain high-risk subgroups, such as children with attention-deficit/hyperactivity disorder or sleep ap- nea, they may perform less well (Bader et al., 2003). A detailed review of different ambulatory technologies for sleep apnea measurement was recently performed (Flemons et al., 2003; Tice, 2005). Most devices have been designed to screen or diagnose sleep apnea. Several novel portable devices that have been informed by a growing knowledge of physi- ological correlates of sleep apnea have been developed. A recent review by the AASM has identified the utility of measuring nasal pressure from a sensor placed in the outer nares, which accurately detects airflow limitation (Krieger et al., 2002), the sine qua non of OSA. Several devices combine this sensor with sensors that measure oxygen saturation, snoring, and other sleep apnea correlates. For example, a relatively simple device has been designed to mea- sure nasal pressure, oximetry, head movement, and snoring with a head band containing these sensors that is placed around the forehead and can be self- applied without glue or skin preparation (Westbrook et al., 2005). The AHI derived using an early version of this device tested in both in-home and in- laboratory settings in a large sample showed sensitivities of 92 to 98 percent and specificities of 86 to 100 percent for identification of sleep apnea. An advantage of such technology includes its potential to easily measure sleep over two or more nights (enhancing reliability) and its potential reduced cost

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222 SLEEP DISORDERS AND SLEEP DEPRIVATION (estimated at 30 to 50 percent of that of in-laboratory polysomnography). There has also been great interest in the use of completely novel sensors that have not been traditionally used in the sleep laboratory, but which are based on growing interests in the autonomic sequelae of sleep apnea. One such device measures peripheral artery tone from a sensor placed on the finger and has been shown to provide estimates of vascular flow, a measure that reflects variations in breathing and sleep-related arousals (Lavie et al., 2000). One wrist-worn device that uses this sensor in combination with sensors measur- ing oxygen saturation, heart rate, and movement has shown promising utility for sleep apnea detection. Preliminary data from one study showed a 95 per- cent sensitivity and 100 percent specificity (Pittman et al., 2004). Other studies have also supported this approach (Ayas et al., 2003), including results from a study of almost 100 individuals (Zou et al., 2006). Another exciting advance is the development of oximeters that are relatively resistant to movement artifact, thus improving the accuracy of such data in unattended settings (Barker, 2002). CHALLENGES TO DEVELOPING AMBULATORY TECHNOLOGIES Despite the promise of this technology, use of portable monitoring for diagnosis or management of sleep disorders has not yet been endorsed by any professional organization. Dozens of studies have been conducted that evaluate different aspects of technology use (ranging from evaluation of the accuracy of individual sensors to use in epidemiological studies to use in case identification); however, very few studies have met rigorous criteria for endorsement of a new diagnostic test, including comparison to a reference standard, blinded assessments, and use of large samples (Tice, 2005). Al- though development and evaluation of new and improved sleep monitors are much needed, the industry has failed to invest in conducting such rigor- ous studies. The National Institutes of Health (NIH) has invested in such assessments mostly through Small Business Innovation Research (SBIR) grants; however, between 2002 to 2005, only 17 SBIR grants were awarded to develop and evaluate new sleep technology, and many of these studies were designed to test feasibility (phase I) rather than efficacy. There are several challenges to technology development and evaluation that may be fairly specific to sleep medicine. Challenges relate to the under- lying uncertainty over: (1) which physiological signals best capture the stresses associated with sleep apnea and thus would most optimally identify patients who are either at increased risk for sleep apnea-related morbidity or who are most likely to require and respond to therapy; and (2) what threshold values, if any, for quantitative data derived from physiological monitoring best identify patients at risk or likely to respond to therapy. The collection of 12 or more channels of physiological data on sleep architec-

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223 ENSURING ADEQUATE DIAGNOSIS AND TREATMENT ture, cardiovascular responses, and disordered breathing potentially pro- vides the clinician a comprehensive panel of data from which to make treat- ment decisions. The influences of reducing this panel of data on clinical decisions and short- and long-term disease management are unclear. Emerg- ing data suggest that different sleep apnea-related outcomes may be differ- entially predicted by alternative indexes of physiological stress captured by polysomnography. One recent cross-sectional study, for example, showed that while indexes of overnight hypoxemia were most strongly associated with glucose impairment, the arousal index best predicted hypertension (Sulit et al., 2006). Thus, monitors that selectively record one set of physi- ological disturbances may be well suited for predicting some, but not all outcomes. Threshold values may also differ according to the physiological outcome of interest. For example, data from the Sleep Heart Health Study suggest that an increased prevalence of hypertension may be observed at a threshold AHI that is higher than the threshold associated with other car- diovascular manifestations (Nieto et al., 2000; Shahar et al., 2001). Such uncertainties hamper technological efforts at choosing sensor “packages” that are most clinically relevant and evaluation procedures that require clear consensus over affection status to determine sensitivity and specificity. Implicit in the challenges noted above are the very limited available data that address the clinical utility of the most commonly considered refer- ence standard of polysomnography, coupled with current practice that focuses on specific numbers obtained from this test to make specific diag- noses. However, the latter practice is actually not well supported by evidence, and there is much debate over which threshold levels define “disease” and what combinations of data should be used to construct each metric (Ryan et al., 1988; Redline and Sanders, 1999). Little available research has evaluated the specific contribution of polysomnography over information obtained by other clinical assessments, including history and examination. As mentioned, although multiple physiological variables are captured, there is no clear consensus on how these data are most optimally combined for case identification or for disease assessment. Historically, the field (including third-party insurers) have used a single metric such as the AHI for defining sleep apnea, or the periodic limb movement index (PLMI) for periodic limb movement disorder, defining disease by using a single cutoff value for each (e.g., AHI greater than 5 for sleep apnea or PLMI greater than 5 for periodic limb movement disorder). However, this ap- proach, which emphasizes the centrality of a single number—and which is known to vary from night to night (Quan et al., 2002)—differs from that in other fields where data from physiological tests are used as one of many indices to gauge disease severity and to follow treatment responses, but are not used as the sole diagnostic instrument. For example, asthma, a common chronic inflammatory disease of the airways, is diagnosed predominantly

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224 SLEEP DISORDERS AND SLEEP DEPRIVATION using a careful history; lung function tests are used to gauge disease severity and treatment responses and sometimes to help differentiate asthma from other respiratory conditions. The issues that plague equipment develop- ment and laboratory access in the sleep laboratory have not impeded the development of lung function laboratories. Rather, the development and accreditation of lung function laboratories and lung function equipment (including portable spirometers) are based on collecting reproducible data that meet physiological criteria for accuracy, independent of the role of such equipment as tools evaluated on their ability to independently classify disease status. It is recognized that the latter requires consideration of mul- tiple factors, including symptoms, level of impairment, response to allergic and irritant triggers, and often empiric responses to therapeutic trials. Other challenges relate to designing studies that specifically address a number of distinct potential applications of portable sleep monitor- ing. These include screening—which is often population-based, and intended to detect cases independent of symptoms; clinical case definition— identification of cases among patients referred because of health concerns; disease management in which sleep monitoring provides quantitative data on progression or regression of disease severity; and epidemiological stud- ies—in which sleep monitoring is used to provide a quantitative assessment of a physiological exposure or outcome. It is important that any given evaluation study of new technologies be designed to address a specific ques- tion or related series of questions. Scoring and Processing of Sleep Studies Current scoring approaches use a system of epoch by epoch scoring (30 seconds per epoch) developed over 40 years ago when polysomnography used only paper-based systems based on analog data. This approach is recognized to be both labor-intensive and time-consuming. Further, reliance on human scorers using visual pattern recognition requires intensive and ongoing train- ing to achieve high reliability (Whitney et al., 1998), which may be lower than that potentially attained by automated methods (which also have their limitations). Visual scoring also may not maximally utilize the spectral com- ponents of the electrophysiological data, which may provide useful informa- tion on sleep architecture. Furthermore, there is a shortage of trained sleep technicians. Currently there are only 2,198 certified technicians to monitor and score sleep tests, far below the need (Association of Polysomnographic Technologists, 1999). Recognizing these issues, the AASM convened a task force in 2004 to reassess current scoring approaches, critically evaluate both sensors and scoring algorithms, and update scoring approaches as appropriate to include digital analysis of electrophysiological data. This report, scheduled

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225 ENSURING ADEQUATE DIAGNOSIS AND TREATMENT for release in 2006, should provide important advances for the diagnosis of chronic sleep loss and sleep disorders. Summary of Formal Evaluation Reviews Three recent in-depth reviews have been performed to examine the effectiveness of portable monitoring devices (Ross et al., 2000; ATS, 2004; Tice, 2005). As described above, these reports were largely aimed at evalu- ating the literature regarding the accuracy of clinical diagnosis relative to reference in lab polysomnography, with some attempt at also evaluating the literature relative to cost-effectiveness and clinical prediction. In 1998, the Agency for Healthcare Research and Quality performed a literature review and meta-analysis on studies of portable monitoring for OSA. The review concluded that at the time there was insufficient evidence to make firm recommendations for use of portable monitoring for the diag- nosis of sleep apnea (Ross et al., 2000). An executive summary on the systematic review and practice param- eters for portable monitoring in the investigation of suspected sleep apnea in adults was published in 2004 by an evidence review committee consisting of members from the American Thoracic Society, the American College of Chest Physicians, and the American Academy of Sleep Medicine (ATS, 2004; Flemons and Littner, 2003). In that summary, the following recommenda- tions were made: • Given the available data, the use of portable device was not recom- mended for general screening. • The use of portable devices was not recommended in patients with comorbid conditions or secondary sleep complaints. • The use of portable devices should require review of raw data by trained sleep specialists. The review committee also recognized the need for further develop- ment of portable devices and suggested several goals for future research. It was found that most studies on portable monitoring were performed pri- marily on white males with OSA who had few comorbidities. The evidence review committee recommended that future studies should include more diverse populations, other than patients with sleep apnea, that are not sub- ject to selection bias. Additional recommendations were that future studies should address clinical predictive algorithms in combination with portable monitoring in the diagnosis of sleep apnea, and study design should assess the cost-effectiveness and outcomes associated with different diagnostic and management strategies.

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226 SLEEP DISORDERS AND SLEEP DEPRIVATION The California Technology Assessment Forum most recently evaluated the evidence that supported use of ambulatory devices over in-laboratory procedures for the purposes of diagnosing sleep apnea (Tice, 2005). The following five technology assessment criteria were identified: • The technology must have final approval from government regula- tory bodies. • The scientific evidence must permit conclusions concerning the effec- tiveness of the technology regarding health outcomes. • The technology must improve health outcomes. • The technical must be as beneficial as any established alternatives. • The technology must be attainable outside of the investigational setting. They determined that only the first two criteria had been met, but the last three were not. This review also identified the paucity of data regarding the “reference standard” (laboratory polysomnography) as improving health outcomes and suggested that a therapeutic trial of CPAP therapy may be a more efficient and clinically relevant approach than use of either in-home or in-laboratory sleep monitoring. Evaluating Daytime Sleepiness There is also a need to improve diagnostic procedures aiming at the quantification of excessive daytime sleepiness and the diagnosis of narco- lepsy and hypersomnia. The current gold standard is the clinical Multiple Sleep Latency Test (MSLT), conducted after nocturnal polysomnography is performed (Littner et al., 2005). Sleepiness is considered consistent with hypersomnia or narcolepsy when a mean sleep latency less or equal to 8 minutes is observed (AASM, 2005). The observation of multiple sleep onset rapid eye movement (REM) periods (SOREMPs) during five naps is consid- ered diagnostic for narcolepsy (see Chapter 3). Problematically however, the MSLT is sensitive to sleep deprivation and sleep-disordered breathing; thus, the test is often difficult to interpret. Population-based studies with the experimental MSLT, a modified version of the MSLT where mean sleep latency, but not SOREMP are measured, suggest that a large portion of the population has a short sleep latency (Kim and Young, 2005) and that the test correlates only partially with subjective measures of excessive daytime sleepiness. This has led to the revised diagnostic criteria that suggest that the MSLT should only be interpreted in the absence of sleep apnea and sufficient sleep prior to the MSLT (total sleep time equal to or greater than 6 hours) (AASM, 2005). Very limited clinical MSLT data are available in population samples, but data to date suggest that 3.9 percent of individuals may be positive for SOREMPs independent of daytime sleepiness (Singh et

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227 ENSURING ADEQUATE DIAGNOSIS AND TREATMENT al., 2005). Similarly, the Maintenance of Wakefulness Test (MWT), a test in which the subject is asked to try not to fall asleep in naps and sleep latency is measured, has been used to objectively measure alertness in drug trials but is not validated to demonstrate an ability to stay awake for patients at risk, for example in medicolegal cases and the evaluation of driving abilities (Littner et al., 2005). As conducted, the MSLT and the MWT are time-consuming and expensive, and validation in the general population sample is lacking. How sleep apnea and prior sleep time in and outside the laboratory affects the occurrence of SOREMPs in MSLTs is not established. It is also unknown whether these tests may not be more valid after a night at home and verifi- cation of sleep with actigraphy or other procedures, a modification that would reduce cost in some cases. Finally, performance tests such as the psychomotor vigilance task, used commonly to evaluate performance after sleep deprivation, may have applications in this area (Dauvilliers and Buguet, 2005), especially if those tests can be adjusted to be used in ambu- latory situations. Biochemical and imaging research aiming at discovering biomarkers of sleep debt and sleepiness is also needed. Other Diagnostic Technologies In addition to the development of ambulatory strategies, efforts are also currently under way to utilize other techniques to diagnose individuals who suffer chronic sleep loss or sleep disorders. These strategies include the devel- opment of genetic and biochemical tests for narcolepsy, magnetic resonance imaging (MRI) to visualize the upper airway in children with OSA, and acoustic reflectometry (a noninvasive ultrasound technique) of the upper air- way to quantify anatomic obstruction of the upper airway in children (Mignot et al., 2002; Arens et al., 2003; Monahan et al., 2002; Donnelly et al., 2004; Abbott et al., 2004). Tests such as the standardized immobilization test or biochemical/imaging measures of brain iron metabolism are being developed to assist in the diagnosis and quantification of severity in restless leg syn- drome (Allen and Earley, 2001; Garcia-Borreguero et al., 2004; Trenkwalder et al., 2005). Actigraphy and other methods are also used to estimate leg movement frequency in outpatients (Kazenwadel et al., 1995; Sforza et al., 2005). Video technologies may also be of value, especially in the diagnosis of individuals with night terrors. Finally, there is a need to establish novel proce- dures to objectively identify abnormalities in insomnia beyond the changes generally observed using sleep questionnaires, logs, and polysomnography (Roth and Drake, 2004). These may involve the use of spectral analysis (Perlis et al., 2001), microstructural cyclic alternating patterns analysis (Parrino et al., 2004), and functional neuroimaging (Drummond et al., 2004; Nofzinger, 2005).

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228 SLEEP DISORDERS AND SLEEP DEPRIVATION The development of polysomnograms that are performed in a local hos- pital and telemonitored by a central sleep laboratory could allow for a single technician to monitor multiple studies from a central location. However, the reliability of these procedures varies (Gagnadoux et al., 2002). FUTURE DIRECTIONS Given the cumbersome nature and cost of the diagnosis and treatment of sleep disorders and sleep loss, the resultant inequities with regard to access, and in order to ensure future quality care, greater investment in the develop- ment of new, and validation of existing, diagnostic and therapeutic technolo- gies is required. Improvement in portable monitoring techniques will likely enhance access to sleep diagnostic services. With the inadequate availability of sleep centers and sleep technicians, not only in the United States but more so worldwide, access to portable diagnostic screening procedures and stream- lining initiation of treatment would clearly be advantageous. In particular, portable monitoring at level III (limited channel polysomnogram of four or more cardiopulmonary bioparameters) or level IV (testing of only one or two cardiopulmonary bioparameters) would help lower health costs and shorten waiting lists. In selected patient populations, portable monitoring in conjunc- tion with inpatient split-night polysomnography or unattended autotitration of nasal CPAP could prove to be the most cost-effective and rational approach to most patients with a clinical profile for moderate to severe sleep apnea syndrome. Research in the design and evaluation of existing and novel diagnostic technologies is also needed in the area of insomnia, hypersomnia, and restless legs syndrome and periodic limb movements. However, the rational application of technology needs to be coupled with the following: • A reexamination of the role of diagnostic testing in case identifica- tion and disease management, clarifying optimal use of objective physi- ological monitoring data (including data obtained from portable monitors) in clinical diagnostic and management algorithms. • Recognition that the development of new physiological monitoring tools needs to be guided by research that clarifies the short- and long-term clinical predictive information of specific channels (including responses to clinical interventions), or combinations of data. This should include consid- eration of the extent to which data from new technologies complement those from other techniques. • Standardization of diagnostic and treatment criteria, language, and technologies. • Investigation of how information from laboratory and portable diag- nosis may interface as complementary rather than competitive technologies.

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229 ENSURING ADEQUATE DIAGNOSIS AND TREATMENT • Investment by industry and the NIH in rigorous evaluation and out- come studies that are designed to test specific questions regarding technol- ogy applications in improving the efficiency of screening, case identifica- tion, and disease management. • Assessment of technologies utilizing indexes to examine their cost- effectiveness. • Development of technologies keeping in mind that treatment of sleep disorders requires a chronic care management scheme (see Chapter 9). • Specific efforts to develop and modify technologies for children. Recommendation 6.1: The National Institutes of Health and the Agency for Healthcare Research and Quality should support the validation and development of existing and new diagnostic and therapeutic technologies. The National Center on Sleep Disorders Research—working with the Trans-NIH Sleep Research Coordinating Committee, the Agency for Health Care Policy and Research, other federal agen- cies, and private industry—should support the evaluation and vali- dation of existing diagnostic and therapeutic technologies. Further, development of new technologies such as ambulatory monitoring, biological markers, and imaging techniques should be vigorously supported. REFERENCES AASM (American Academy of Sleep Medicine). 2005. The International Classification of Sleep Disorders. Westchester, IL: AASM. Abbott MB, Donnelly LF, Dardzinski BJ, Poe SA, Chini BA, Amin RS. 2004. Obstructive sleep apnea: MR imaging volume segmentation analysis. Radiology 232(3):889–895. Allen RP, Earley CJ. 2001. Restless legs syndrome: A review of clinical and pathophysiologic features. Journal of Clinical Neurophysiology 18(2):128–147. Ancoli-Israel S, Clopton P, Klauber MR, Fell R, Mason W. 1997. Use of wrist activity for monitoring sleep/wake in demented nursing-home patients. Sleep 20(1):24–27. Antle DW, Reid RA. 1988. Managing service capacity in an ambulatory care clinic. Hospital and Health Services Administration 33(2):201–211. Arens R, McDonough JM, Corbin AM, Rubin NK, Carroll ME, Pack AI, Liu J, Udupa JK. 2003. Upper airway size analysis by magnetic resonance imaging of children with ob- structive sleep apnea syndrome. American Journal of Respiratory and Critical Care Medi- cine 167(1):65–70. Association of Polysomnographic Technologists. 1999. The APT Demographic, Salary, and Educational Needs Survey. Lenexa, KS: APT. ATS (American Thoracic Society). 2004. Executive summary on the systematic review and practice parameters for portable monitoring in the investigation of suspected sleep apnea in adults. American Journal of Respiratory and Critical Care Medicine 169(10):1160– 1163.

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