The comparison between APOE-4 carriers and noncarriers in the total sample of AD patients showed no significant difference in lagged phase synchronization (t max = 2.96; p = 0.81, two-tailed, corrected). We further explored differences in functional connectivity according to APOE status in AD subgroups. Because of the small number of patients in the severe AD group (n = 17), data from patients with moderate and severe AD were pooled. The comparison of carriers and noncarriers in the subgroup of moderate/severe AD revealed no statistical significance (t max = 2.94; p = 0.88, two-tailed, corrected). However, when analyzing carriers vs. noncarriers among patients with early AD, we found decreased alpha2 lagged phase synchronization between lateral frontal areas (carriers: 0.034±0.012, noncarriers: 0.084±0.055; t = −4.08, p = 0.045 corrected) and parieto-temporal areas (carriers: 0.040±0.019, noncarriers: 0.10±0.067; t = −3.98, p = 0.049 corrected) across hemispheres (Fig. 5).
