ANOMALY JUDGMENTS OF SUBJECT-PREDICATE RELATIONS IN ALZHEIMERS-DISEASE

Claims that patients with probable Alzheimer's disease (AD) have seman tic memory difficulty have received equivocal support. A common assump tion has been that defining or core information determines the truth v alue of word meaning on measures requiring semantic memory such as cat egory membership judgments or confrontation naming, but this assumptio n may not be valid. In the present study, we assessed the comprehensio n of subject-predicate sentences independent of their truth value by a sking AD patients to judge the coherence of statements such as ''The t ulip is tall'' or ''The tulip is jealous.'' We found that AD patients are significantly more impaired than controls at judging the coherenc e of these simple subject-predicate sentences. Moreover, AD patients w ere more successful at judging the coherence of statements that contai n attributes with a narrow scope of reference compared to attributes w ith a broad scope of reference. These findings support the hypothesis that AD patients have a semantic memory impairment and suggest a speci fic deficit processing the network of semantic relations underlying wo rd meaning in semantic memory. (C) 1996 Academic Press, Inc.