CHANGES IN SEMANTIC MEMORY IN EARLY-STAGE ALZHEIMERS-DISEASE PATIENTS

The types and number of exemplars of categories that are retrieved fro m semantic memory differentiate elderly normal controls and early stag e Alzheimer's disease (AD) patients. Elderly normal controls generated more uncommon exemplars from closed semantic categories (fruits and v egetables) than did AD patients 2 1/2 years prior to the presumed onse t of AD. AD patients, however, were just as productive as elderly norm al controls in generating associations to open categories (letters). T he findings suggest that one of the early cognitive symptoms of AD is changes in availability of uncommon exemplars of semantic networks.