Material-specific memory loss in probable Alzheimer's disease.

This study extends previous work analysing functional dissociations occurring in patients with Alzheimer's disease (AD) by demonstrating that material-specific memory loss is common. The pattern of neuropsychological dysfunction in 191 patients with probable AD was examined and 13% presented with material-specific memory loss. Thirteen patients had impaired immediate verbal recall, but normal non verbal recall and 12 had impaired non verbal recall and normal verbal memory. These patterns appeared to be related to a specific memory deficit and were probably not secondary to associated cognitive impairments. These data confirm earlier observations that the memory defect in AD can be material-specific, and suggest that these patterns of impairment should be viewed as a focal sparing of function.