LEXICAL ACQUISITION IN PROBABLE ALZHEIMERS-DISEASE

Patients with probable Alzheimer's disease (pAD) were exposed to a new verb in a naturalistic fashion. We probed their knowledge of the word 's semantic and grammatical characteristics for several minutes follow ing this exposure, and compared this with their performance on paralle l measures assessing known words. Significant differences were seen be tween pAD patients and controls in the acquisition of the new verb's s emantic meaning and its argument structure, but pAD patients did not d iffer from controls in the acquisition of the new word's grammatical f orm class. Individual patient analyses demonstrated parallel deficits restricted to the semantic meaning and argument structure of the new w ord and known words in several pAD patients, suggesting that a selecti ve language impairment contributed to their word learning deficit. Thi s pattern is consistent with an intimate relationship between semantic meaning and argument structure in semantic memory. Other pAD patients had difficulty learning about all aspects of the new word, despite go od performance with known words, suggesting that compromised memory ma y have limited their lexical acquisition. (C) 1997 Academic Press.