LEXICAL SEMANTIC AND ASSOCIATIVE PRIMING IN ALZHEIMERS-DISEASE

Semantic memory impairment was investigated in patients with probable Alzheimer's disease (AD) using a threshold oral word reading task to a ssess priming of different lexical relationships. Healthy elderly cont rols showed significant priming for associatively related nouns (tempe st-teapot) and also for nouns semantically related either because both designate basic-level exemplars of a common superordinate category (c ousin-nephew) or because the target names the superordinate category o f the prime (daughter-relative). AD patients, in contrast, showed pres erved priming of lexical associates but impaired priming of certain se mantic relationships. They showed no priming between words designating coordinate exemplars within a category, despite preserved priming of the superordinate category label. Findings are consistent with the vie w that at least part of the semantic deficit in AD is due to disruptio n of semantic knowledge that affects relationships among basic-level c oncepts, more than the relationships between these concepts and their corresponding superordinate category of membership.