PREVALENCE, INCIDENCE, AND FUNCTIONAL SIGNIFICANCE OF EXECUTIVE COGNITIVE IMPAIRMENT AMONG OLDER ADULTS

1. PREVALENCE, INCIDENCE, AND FUNCTIONAL SIGNIFICANCE OF EXECUTIVE COGNITIVE IMPAIRMENT AMONG OLDER ADULTS

2. Jim Grigsby (Medicine/Geriatrics, Center forHealth Services Research)Judith Baxter (Preventive Medicine & Biometrics)Angela Brega (Center for Health Services Research)Terry B. Eilertsen (Center on Aging) Richard F. Hamman (Preventive Medicine & Biometrics)Kathryn Kaye (Medicine/Geriatrics, V.A.M.C.)Andrew M. Kramer (Medicine/Geriatrics, Center on Aging)Susan M. Shetterly (Preventive Medicine, Kaiser)

3. 3 Executive Cognitive Functions The executive cognitive abilities are a set of complex dissociable cognitive skills including planning, organization, response to novelty, and working memory. One of the more fundamental executive functions is the ability to use intentions to guide performance of goal-directed behavior. This involves both the ability to initiate purposeful activity independently, and to inhibit irrelevant or inappropriate activity. Persons with such disorders are unable to regulate their own behavior, and require the provision of encouragement, external structure, and supervision.

4. 4 Primary Objectives In the San Luis Valley Health & Aging Study (SLVHAS), a population-based study of chronic illness and disability among the elderly, we set out to: 1. assess the prevalence of executive cognitive impairment among older adults; 2. assess the incidence of executive cognitive impairment among older adults; and 3. evaluate the contribution of executive cognitive abilities to the performance of activities of daily living (ADLs) and instrumental ADLs (IADLs).

5. 5 Primary Objectives (Continued) In a series of studies with older adults, including outpatient clinical samples, community-dwelling persons, and rehabilitation inpatients, we set out to: 1. Evaluate the contribution of executive cognitive function (ECF) to performance of activities of daily living (ADLs) and instrumental ADLs (IADLs). 2. Assess the role of ECF in behavioral disorders marked by impulsivity and disinhibition. 3. Assess the role of ECF in behavioral disorders marked by apathy and failure to initiate purposeful behavior.

6. 6 Samples Prevalence in the SLVHAS, age 60-99 (n = 1,313) Incidence in the SLVHAS, age 60-99 (n = 1,112) ADLs/IADLs and physical limitations in the SLVHAS, age 60-99 (n = 1,158) Stroke rehabilitation inpatients, age 65-96 (n = 246) Med-surgical rehab inpatients, age 65-99 (n = 150) Hip fracture rehab inpatients, age 65-98 (n = 224) V.A.M.C. geriatric clinic outpatients, age 63-103 (n = 50)

7. 7 Measures Independent Variables: Behavioral Dyscontrol Scale (BDS)--executive functioning Mini Mental State Exam (MMSE)--general mental status Center for Epidemiologic Studies Depression Scale (CES-D) or Geriatric Depression Scale (GDS) Comorbidity Demographics (Age, education, ethnicity, acculturation) Dependent Variables: Structured Assessment of Independent Living Skills (SAILS) Self-Report ADL and IADL measures from the Longitudinal Study of Aging Barthel ADL Index Nagi/Rosow-Breslau physical disability measure

8. 8 Results: Prevalence & Incidence 33.7% showed mildly impaired ECF. 16.4% showed moderately to severely impaired ECF. Prevalence of ECF deficits increased with age, with 44.7% of nonagenarians moderately to severely impaired. Lower educational level was strongly associated with poor ECF performance. At a mean of 21-month follow-up, mean BDS score had declined by 0.25 sd. Those over 84 had a mean decline of ~ 0.75 sd on the BDS. Lower education was associated with greater incidence of ECF impairment.

9. 9 Results: Functional Status Consistent results were obtained across all samples: ECF is a stronger predictor of functional status than MMSE, especially for observed performance. ECF is strongly associated with both apathy and impulsivity. ECF is strongly associated with the capacity to initiate purposeful activity independently. Though the BDS is correlated with MMSE, 10% to 20% of older adults have moderately to severely impaired ECF but a normal MMSE score.

10. 10 Conclusions: Prevalence & Incidence The capacity to use intentions to engage in goal-directed activity--inhibiting irrelevant behavior and initiating purposeful behavior--is impaired in a significant percentage (~ 1/3) of persons over the age of 60. One in six older adults is moderately to severely impaired in executive functioning. Both the prevalence and the incidence of ECF impairment increase with advancing age and lower educational levels. Such impairment may be seen even among persons with an apparently normal mental status examination.

11. 11 Conclusions: Functional Status Persons with impairment of ECF are generally impaired in their capacity to engage independently in ADLs and IADLs, even when they are able to perform these activities. They also are more likely to be disinhibited, to fail to initiate appropriate behavior, and to lack awareness of their limitations. Because their capacity to regulate their own behavior is deficient, they are unlikely to be helped by interventions that require them to take initiative or to function autonomously. Instead, these persons require active intervention by other individuals.