APOE and Alzheimer disease: To date, M/EEG studies in elderly APOE-ɛ4 carriers have shown changes in the oscillatory alpha band (Babiloni et al., 2006; Canuet et al., 2012; de Waal et al., 2013; Jelic et al., 1997; Kramer et al., 2008; Ponomareva et al., 2008) and in the much lower-frequency delta band (Cuesta et al., 2015; de Waal et al., 2013) in regions similar to those reduced in AD and MCI.