. "Conceptual Issues in the Measurement of Work Disability." The Dynamics of Disability: Measuring and Monitoring Disability for Social Security Programs. Washington, DC: The National Academies Press, 2002.
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The Dynamics of Disability: Measuring and Monitoring Disability for Social Security Programs
individual, Nagi uses the term functional limitations to represent restrictions in the basic performance of the person. An example of basic functional limitations that might result from a cerebrovascular accident could include limitations in the performance of locomotor tasks, such as the person’s gait, and basic mobility, such as transfers, or in nonphysical tasks, such as communication or reasoning. Such functional limitations might or might not be related to specific impairments (secondary to the cerebrovascular accident) and thus are seen as distinct from organ or body system disturbances.
At this point, a “work disability” example will illustrate the distinctions being drawn between the various concepts within Nagi’s Disablement Model. Two patients with Parkinson’s disease may enter the Social Security work disability benefits determination process with very similar clinical profiles. Both may have moderate impairments such as rigidity and bradykinesia. Their patterns of function may also be similar with a characteristically slow, shuffling gait, and slow deliberate movement patterns. Their work role patterns, however, may be radically different. One individual may have restricted his or her outside activities completely, need help dressing in the morning, spend most of the time indoors watching television, be depressed, and be currently unemployed. The other may be fully engaged in his or her social life, receive assistance from a spouse in performing daily activities, be driven to work, and, through workplace modification, be able to maintain full-time employment. The two patients present very different work disability profiles yet have very similar underlying pathology, impairment, and functional limitation profiles.
Elaboration of Nagi’s Disablement Model
In their work on the disablement process, Verbrugge and Jette (1994) maintained the basic concepts of the Nagi Disablement Model and Nagi’s original definitions. Within the dimension of disability, however, they categorized subdimensions of social roles that can be considered under Nagi’s concept of disability. Some of the most commonly applied dimensions include the following:
Activities of daily living (ADL)—including behaviors such as basic mobility and personal care.
Instrumental activities of daily living (IADL)—including activities such as preparing meals, doing housework, managing finances, using the telephone, and shopping.
Paid and unpaid role activities—including performing one’s occupation, parenting, grandparenting, and being a student.