factor for cognitive impairments in Alzheimer's disease and normal aging, was associated with reduced EEG power, particularly in the alpha frequency band, as well as weaker inter-regional connectivity in the right hemisphere in a young population aged 19-21 (Lee et al., 2012). The the epsilon4 isoform variant is associated with reduced efficiency of proteolytic break-down of beta-amyloid, a peptide that builds up at abnormal levels in Alzheimer's disease (Jiang et al., 2008). Another study showed that among patients with Alzheimer disease, ApoE-4 allele carriers had reduced alpha activity in the left hemisphere (Canuet et al., 2012). A study involving younger and older adults showed that ApoE-4 carriers and non-carriers differed with respect to EEG reactivity to hyperventilation in an age-dependent manner, such that the younger ApoE-4 carriers had excessive reactivity of EEG to the HV, while older ApoE-4 carriers showed lower reactivity than non-carriers. Overall, ApoE-4 carriers showed more pronounced age-related decrease in EEG reactivity to hyperventilation, suggesting that ApoE-related pathology in old age may be mediated by vascular factors (Ponomareva et al., 2012).
