Effects of aging and of Alzheimer's disease on verbal memory.

This study aimed to define the verbal memory profiles of very old normal subjects and subjects with Alzheimer's Disease, and to identify verbal memory indices having the highest discriminant power. Forty-three old normal subjects (mean age = 71 years, SD = 3, range = 65-75), 39 very old normal subjects (mean age = 81 years, SD = 4, range = 76-87), and 45 Alzheimer's patients (mean age = 70 years, SD = 5, range = 59-78) received the Rey test of verbal memory and the WAIS-R Digit Span forward and backward. All but one of the indices could distinguish very old from Alzheimer's subjects. A discriminant analysis disclosed a verbal memory profile of Alzheimer type in 15.4% of the very old group and of very old type in 16.2% of the Alzheimer's patients. Rate of forgetting, immediate and delayed Rey indices, and the true positive responses were, in decreasing order, the main determinants of the discriminant function. Thus, all of the components of verbal memory are differently affected by aging and Alzheimer's disease and contribute to define individual verbal memory profiles.