Recall of anomalous sentences in dementia and amnesia.

Alzheimer-type dementing patients were compared with amnesic (Korsakoff) patients, depressed patients, and healthy controls in the immediate recall of semantically anomalous sentences. It was found that the dementing (Alzheimer) patients were severely impaired in their recall of these sentences, but that the amnesic (Korsakoff) patients were not. Alzheimer patients have a severe impairment of short-term memory, and it is argued that this deficit may make Alzheimer patients especially dependent upon the presence of semantic cues in immediate verbal recall--hence, the removal or reversibility of these cues results in a collapse of their performance. Other research has indicated that Alzheimer patients also show impaired semantic processing, and the possible interaction of their short-term memory and semantic processing deficits is briefly discussed.