APOE and Cognitive impairment: In other studies, the interaction among cognitive impairment, Apoε4, and schooling presents contradictory evidence; Seeman et al.,35 Ishioka,36 and Vemuri et al.37observed that the presence of at least one ε4 allele reduces the protective effect of education on cognitive function, evidenced by a lower score of Short Portable Mental Status Questionnaire in subjects carrying ε4 and with at least 9 years of schooling.