APOE and Alzheimer disease: The ApoE4 genotype is thought to contribute to neurodegenerative processes, negatively impacting cortical activity in both healthy individuals and those with AD [19]. Since the ApoE4 allele is a known genetic risk factor for AD [20], individuals with the ApoE4 allele may have an elevated susceptibility to the neurodegenerative changes associated with abnormal EEG slowing.