Alzheimer's disease and feeling-of-knowing for knowledge and episodic memory.

The metamemory (knowledge of the veracity of memories) of moderately impaired Alzheimer's patients was compared to that of aged controls. Despite their profoundly impaired recall of information from both long-term (knowledge) and recent (episodic) memory, Alzheimer's patients were as accurate as controls in assigning confidence ratings related to the probability that their recalls were correct. They were impaired, however, at predicting the likelihood that they would subsequently recognize correct answers (feeling-of-knowing) to knowledge memory questions which they had been unable to recall correctly. Nevertheless, their performance on this task did exceed chance. Thus, the moderately impaired Alzheimer's patient demonstrates intact awareness of the veracity of recall from knowledge and episodic memory but shows impaired feeling-of-knowing for knowledge memory.