The relationship between neuropsychological performance and daily functioning in individuals with Alzheimer's disease: ecological validity of neuropsychological tests.

The current study examined the relationship between neuropsychological test performance and functional status in 42 individuals diagnosed with Alzheimer's disease. A comprehensive battery of cognitive tests was employed in order to assess a wide range of neuropsychological abilities. Functional status was measured through the use of both a performance-based scale of activities of daily living (an expanded version of the Direct Assessment of Functional Status; DAFS, Loewenstein et al., 1989), and by a caregiver/informant-based rating scale (Instrumental Activities of Daily Living; IADL, Lawton & Brody, 1969). Findings suggest that neuropsychological functioning is moderately predictive of functional status. Using multiple regression analyses, neuropsychological variables accounted for 25% of the variance in the IADL and 50% of the variance in the DAFS. Individual domains of both functional measures were also significantly predicted by the neuropsychological variables. The findings provide evidence of a relationship between neuropsychological test performance and ADLs in an Alzheimer disease patient population.