Lexical decision and priming in Alzheimer's disease.

Patients with probable Alzheimer's disease (AD) were no faster at making lexical decisions to targets preceded by a semantic prime than to those preceded by an unrelated prime, in contrast to the facilitatory effect of semantic primes for controls. Fewer errors were made by both subject groups on the targets that followed related items, indicating the preservation of associative relationships in AD. The AD patients and controls showed similar effects on lexical decision of repetition priming, word frequency, and the degree to which nonwords approximated real words. The abnormal priming effect in AD may stem from increased susceptibility to lateral inhibition in the semantic network.