COGNITIVE CORRELATES OF FUNCTIONAL-CAPACITY IN ELDERLY DEPRESSED VERSUS PATIENTS WITH PROBABLE ALZHEIMERS-DISEASE

This study investigated ecological validity of cognitive measures with functional capacity among 19 patients diagnosed with probable Alzheimer's disease (AD), 27 elderly depressed without cognitive decline, and eight elderly depressed with cognitive decline (4-point decline on Folstein Mini-mental State Examination; MMSE). We employed the Mattis Dementia Rating Scale (MDRS) to assess cognitive performance and the Dementia Behavioral Scale (DBS) to measure functional capacity. These instruments provide both a total score and individual subtest scores. A series of one-way analysis of variance (ANOVA) tests on the MDRS and DBS total scores revealed AD patients to be significantly impaired, compared to both depressed samples, and depressed patients with cognitive decline impaired relative to depressed patients without decline. For AD patients, significant correlations exist between the MDRS perseveration, memory, and attention-concentration subtests and the DBS total score. For depressed patients with cognitive decline, the perseveration subtest correlated with the DBS total score. Functional decline in AD, therefore, may relate to cognitive deficits associated with more widespread cortical impairment. In contrast, functional decline in elderly depressed appears to relate to cognitive impairment associated primarily with frontal systems.