EFFECT OF NORMAL AGING AND OF ALZHEIMERS-DISEASE ON EPISODIC MEMORY

Performances of 12 patients with Alzheimer's disease (AD), 15 healthy elderly subjects and 20 young healthy volunteers were compared on two episodic memory tests. The first, a learning test of semantically rela ted words, enabled an assessment of the effect of semantic relationshi ps on word learning by controlling the encoding and retrieval processe s. The second, a dual coding test, is about the assessment of automati c processes operating during drawings encoding. The results obtained d emonstrated quantitative and qualitative differences between the popul ations. Manifestations of episodic memory deficit in AD patients were shown not only by lower performance scores than in elderly controls, b ut also by the lack of any effect of semantic cues and the production of a large number of extra-list intrusions. Automatic processes underl ying dual coding appear to be spared in AD, although more time is need ed to process information than in young or elderly subjects. These fin dings confirm former data and emphasize the preservation of certain me mory processes (dual coding) in AD which could be used in future thera peutic approaches.