The pattern of deficit in different memory components in normal aging and dementia of Alzheimer's type

The study explored differential patterns of deficits in different memory components as a function of dementia severity. Three groups of 58 subjects each were used: (1) highly functioning elderly who are free of neurological or psychiatric symptoms; (2) individuals with early signs of memory disturbance, whose MMSE scores were > or = 24; and (3) individuals with MMSE scores below 24, who meet criteria for DAT. Performance on the tests that assess different memory components was compared for the three groups. Results suggest pronounced change in acquisition component of memory at the onset of dementia, whereas retrieval from remote memory discriminates well between the mild and the more advanced phases of the disease. Retrieval from recent memory deteriorates more gradually. Based on these results, efficiency of different memory mechanisms was discussed.