Different patterns of cognitive slowing produced by Alzheimer's disease and normal aging.

Aging has previously been shown to produce a generalized proportional slowing of all cognitive operations. In contrast, the present results suggested that Alzheimer's disease produces a disproportionate reduction in the speed with which patients carry out one or more mental operations. The tasks that demented patients found particularly difficult involved either a self-directed search of their lexicon or the use of familiarity information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)