MEMORY PERFORMANCES IN YOUNG, ELDERLY, AND VERY OLD HEALTHY-INDIVIDUALS VERSUS PATIENTS WITH ALZHEIMERS-DISEASE - EVIDENCE FOR DISCONTINUITY BETWEEN NORMAL AND PATHOLOGICAL AGING

In this study we compared memory performances of 29 probable patients with AD (17 mildly and 12 moderately demented) with those of 39 health y young subjects, 36 elderly subjects (matched with the AD group for a ge and years of schooling), and 19 healthy very old subjects. In most of the memory tasks used in the present study, a progressive decline i n performance was observed passing from the Young to the Elderly to th e Very Old to the AD group. However, patients with AD were selectively impaired in the backward reproduction of verbal and spatial span sequ ences and in the semantic encoding of verbal material. These data are consistent with the hypothesis of not only quantitative but also a qua litative discontinuity between the process of normal aging and the dem entia syndrome.