Cognitive and Physical Basis of Disablement in Older Adults
Funded by: National Institute of Health
Year funded: 2001
Steven M. Albert, PhD, Professor of Behavioral and Community Health Sciences, Graduate School of Public Health, University of Pittsburgh
Jane Bear-Lehman, Ph.D., OTR, FAOTA, Associate Professor, Department of Occupational Therapy, New York University
Ann Burkhardt, OTR< OTR/L, Associate Professor and Division Director, School of Health Professions, Long Island University
“Disablement” refers to the sequence of events resulting in disability among older adults. In a commonly accepted model of disablement, the antecedent of disability is “functional limitation,” defined as a limitation in the abilities or skills needed to undertake daily activities. The antecedent of functional limitation is “impairment,” a deficit in underlying bodily systems. The rationale for developing measures of functional limitation is well stated by Guralnik (1989), who pointed out that measures of impairment by themselves do not give specific information on the relevance of these deficits to the actual activities an individual might perform. In this research, we define “functional limitation” antecedent to disability in activities of daily living as deficits in motor and cognitive skills used in performing daily activities. These skill elements (such as sequencing steps in a task, organizing a workspace, or maintaining bodily alignment) have been well-defined, with clear scoring criteria, in the Assessment of Motor and Process Skills (AMPS) (Fisher 1997), an occupational assessment tool for rating functional limitation in the activities of daily living.
In this 5-year observational cohort study, we will follow 360 elders recruited from an existing multiethnic community-based study, the Washington Heights-Inwood Columbia Aging Project (WHICAP), all of whom will have mild-to-moderate disability and not meet criteria for dementia. Within disability groups (1, 2 , or 3 domains based on self-reports), half of the subjects will be cognitively normal and half will have mild cognitive impairment or questionable dementia.
The primary aim is to assess the direct effects of impairment (deficits in strength, range of motion, dexterity, sensation, balance) on disability (self-reported difficulty in ADLs), as well as indirect effects: that is, the degree to which impairment causes disability because it affects more general skills and abilities used in performing tasks. This relationship will be examined in groups defined by disability and cognitive status, as well as in the different sociocultural groups that make up the WHICAP sample (white, African-American, Hispanic). The relationship between changes in reported disability and changes in motor and cognitive skills will be investigated in prospective analyses. Finally, we will assess the accuracy of self- and proxy-reports of disability relative to a clinical judgment of disability.