Differences in executive functioning between Alzheimer's disease and subcortical ischemic vascular dementia.

The present study examined the performance of 114 individuals (62 males, 52 females) on a variety of tests purported to measure executive abilities. Participants were diagnosed with possible or probable Alzheimer's disease (AD), subcortical ischemic vascular dementia (SVaD), or were normal controls (NoDx). Groups were matched for age and education, and clinical groups were matched for severity of dementia. Multivariate and univariate analyses of variance were performed which indicated that the AD and SVaD patients differed from the NoDx on all measures of executive functioning. Further, the AD group made significantly more episodic memory errors than the SVaD group. On the other hand, consistent with previous research, the SVaD group performed significantly better than the AD group on recognition memory, but not on free recall measures. Present findings suggest that AD patients have more executive self-monitoring problems than SVaD patients do, but SVaD patients have more retrieval problems (executive memory search), suggesting a fractionation of executive abilities. Thus, differences between dementia groups depend on the nature of the executive function assessed.