Despite an increasing body of literature on APOE-brain networks relationship in cognitively healthy individuals, little has been reported on the effect of APOE genotype on resting-state functional connectivity in AD. Our results showed a significant decrease in lagged phase synchronization in the alpha2 band affecting lateral frontal and parieto-temporal areas across hemispheres. An EEG study by Jelic et al. using classical coherence analysis compared 10 patients carrying two ε4 alleles, 14 with one ε4 allele and 17 noncarriers with 18 healthy subjects in whom the APOE genotype was not determined. As a result, homozygous patients showed reduced connectivity with temporal and parietal regions [35]. However, the fact that a direct comparison of AD patient subgroups according to APOE-4 status was not performed, and additionally, the control group had unknown APOE genotype, limits the interpretation of the findings regarding the role of APOE-4 on AD functional connectivity. Kramer et al. in an EEG synchronization likelihood study assessed APOE-4 effects on functional connectivity across patients with AD and subjects with subjective memory complaints who served as controls. They noted that among APOE-4
