Previous studies provided inconsistent evidences for the effect of apolipoprotein E ɛ4 (APOE ɛ4) status on the visuospatial working memory (VSWM). Our study was the first investigation with event-related potential (ERP) to explore the effect of APOE ɛ4 on VSWM in healthy elders and aMCI patients.

The aim was to investigate the effect of APOE ɛ4 on VSWM with event-related potential (ERP) study in healthy elders and aMCI patients.

Thirty-nine aMCI patients (27 APOE ɛ4 non-carriers and 12 APOE ɛ4 carriers) and 43 their matched control (25 APOE ɛ4 non-carriers and 18 APOE ɛ4 carriers) performed an N-back task, a VSWM paradigm that manipulated the number of items to be stored in memory.

Our study detected reduced accuracy and delayed mean correct response time in aMCI patients than healthy elders. P300 was elicited by VSWM and its amplitude was lower in aMCI patients at the central-parietal and parietal electrodes than healthy controls. In healthy elders, P300 amplitude declined prior to task performance change in APOE ɛ4 carriers than non-carriers. Regarding aMCI patients, P300 amplitude result revealed exacerbated VSWM deficits in APOE ɛ4 carriers than APOE ɛ4 non-carriers. Additionally, standardized low-resolution brain electromagnetic tomography analysis (s-LORETA) result showed enhanced brain activation in right parahippocampal gyrus during P300 time range in APOE ɛ4 carriers than non-carriers in aMCI patients (Fig. 1, Table 1, Table 2).

It demonstrated that P300 amplitude might serve as a biomarker for recognizing aMCI patients and contribute to early detection of worse VSWM in APOE ɛ4 carriers than non-carriers.