Neuropsychological functioning in depressed versus nondepressed participants with Alzheimer's disease

Differences in cognitive functioning between participants with Alzheimer's Disease (AD) reporting depressive symptomatology (AD-Dep; n = 37) and a control group of nondepressed participants with AD (AD-Con; n = 98) were investigated based on hypothesized impairments of attention/concentration, psychomotor speed, and simple motor speed. Groups did not differ in age, education, overall severity of dementia, auditory comprehension, or use of psychotropic medications. AD-Dep participants performed significantly more poorly than AD-Con participants on 3 of the 13 measures on which they were hypothesized to exhibit greater impairment (WAIS-R Block Design, WAIS-R Digit Symbol, and speeded motor programming); and there were trends toward poorer performance on four additional measures (WAIS-R Object Assembly, WAIS-R Picture Arrangement, WAIS-R Digit Span-backward, and letter fluency). There was only one significant effect for the 13 measures on which no group differences were hypothesized; the AD-Dep participants unexpectedly obtained better WMS-R Logical Memory delayed recall scores than the AD-Con participants. Finally, AD-Dep participants exhibited an unexpected pattern of greater right hand advantage on the Finger Tapping Test.