Abstract

In this study, to compare the explicit and implicit memory decline pattern of Alzheimer's disease high risk group with low group assigned by 7-minute screening test, ADAS-Cog and computerized priming task were administered to the old with subjective memory problem. At fist, there is significant mean difference in explicit memory performance but there is not in implicit memory performance between two groups. And as for low risk group, as the cognitive function measured by K-MMSE declines, the explicit memory significantly declines, too while the implicit memory maintains. As for high risk group, as the cognitive function declines, the explicit memory shows no change but the implicit memory declines. The dissociation of the two types of memory observed in this study indicates that as cognitive deterioration progresses the explicit memory declines first among the Alzheimer's disease low risk group while as cognitive deterioration progresses the implicit memory declines successively. According to this results, implicit memory can be a index indicating the severity of the Alzheimer's disease.