Apolipoprotein e ϵ4 Allele Is Associated with Reduced Retention of the "where" Memory Component in Cognitively Intact Older Adults

Objective: The present study investigated the effect of the apolipoprotein E (ApoE) ?4 allele on the four memory components (i.e., who, when, where, and what) among cognitively intact older adults. Methods: Participants comprised 47 cognitively intact older adults, who were classified into 2 groups based on the presence or absence of at least 1 ApoE ?4 allele. All participants completed standardized neuropsychological tests, including the Logical Memory subtest of the Wechsler Memory Scale-III with a revised scoring method. Results: The results revealed that recollection for each component followed a pattern of who > what > when = where. Furthermore, a significant group-by-component-by-condition interaction indicated that the presence of the ApoE ?4 allele resulted in a disproportionately detrimental effect on the where component retention in the verbal episodic memory task; this finding was significantly correlated with hippocampal volumes. Conclusion: These results highlighted the importance of evaluating the subcomponents of verbal episodic memory to detect subtle cognitive differences related to ApoE ?4 status, which could help elucidate the mechanism behind the cascades caused by ApoE ?4 in the trajectories of cognitive aging. ? 2019 The Author(s) 2019. Published by Oxford University Press. All rights reserved.