Signal-detection analysis of nonverbal recognition memory in dementia

A signal-detection analysis was applied to performance on two non-verbal recognition memory tasks for 21 subjects with presumed dementia of the Alzheimer type, 19 subjects with presumed multi-infarct dementia, and 19 elderly depressed subjects. Performance was best for the depressed and worst for the Alzheimer subjects. Response bias did not differ significantly among groups. Within the depressed group, more impaired and older subjects were more conservative on one test. Correlations suggested that the sensitivity and response-bias measures may depend on the type of material used and so have limited generality.