Semantic processing in patients with Alzheimer's disease

Ten patients with dementia of the Alzheimer type and 10 normal controls performed a lexical decision, semantic facilitation task. The performance of the patients differed from that seen in normals. A post hoc subdivision of the data suggested that the deviation from normality was not uniform throughout the patient population. Six of the 10 Alzheimer patients showed an advantage of related primes over unrelated primes, while 4 of the 10 were actually faster in the unrelated condition than in the related condition. Nevertheless, both groups of Alzheimer patients showed lexical decision latency differences between unrelated and related prime words, suggesting that patients with Alzheimer's disease are sensitive to the semantic relationships between words.