The Effect of Apolipoprotein E ?4 (APOE ?4) on Visuospatial Working Memory in Healthy Elderly and Amnestic Mild Cognitive Impairment Patients: An Event-Related Potentials Study.
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ABSTRACT: Background: Apolipoprotein E (APOE) ?4 is the only established risk gene for late-onset, sporadic Alzheimer's disease (AD). Previous studies have provided inconsistent evidence for the effect of APOE ?4 status on the visuospatial working memory (VSWM). Objective: The aim was to investigate the effect of APOE ?4 on VSWM with an event-related potential (ERP) study in healthy controls (HC) and amnestic mild cognitive impairment (aMCI) patients. Methods: The study recorded 39 aMCI patients (27 APOE ?4 non-carriers and 12 APOE ?4 carriers) and their 43 matched controls (25 APOE ?4 non-carriers and 18 APOE ?4 carriers) with an 64-channel electroencephalogram. Participants performed an N-back task, a VSWM paradigm that manipulated the number of items to be stored in memory. Results: The present study detected reduced accuracy and delayed mean correct response time (RT) in aMCI patients compared to HC. P300, a positive component that peaks between 300 and 500 ms, was elicited by the VSWM task. In addition, aMCI patients showed decreased P300 amplitude at the central-parietal (CP1, CPz, and CP2) and parietal (P1, Pz, and P2) electrodes in 0- and 1-back task compared to HC. In both HC and aMCI patients, APOE ?4 carriers showed reduced P300 amplitude with respect to non-carriers, whereas no significant differences in accuracy or RT were detected between APOE ?4 carriers and non-carriers. Additionally, standardized low-resolution brain electromagnetic tomography analysis (s-LORETA) showed enhanced brain activation in the right parahippocampal gyrus (PHG) during P300 time range in APOE ?4 carriers with respect to non-carriers in aMCI patients. Conclusion: It demonstrated that P300 amplitude could predict VSWM deficits in aMCI patients and contribute to early detection of VSWM deficits in APOE ?4 carriers.
SUBMITTER: Gu LH
PROVIDER: S-EPMC5434145 | biostudies-literature | 2017
REPOSITORIES: biostudies-literature
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