APOE and dementia: In general, APOE4 and its association with different measurable clinical variables such as dementia severity [84], neuropsychological scores [85], pathology burdens [86], cortical morphometry [5], morphometric-MRI [87,88], functional-MRI [89–91], electroencephalographic (EEG) [92,93] and magnetoencephalographic (MEG) signals [94], evoked potentials (EPs) changes [95,96], and other methods [97] has been investigated much more extensively than APOE2 [98–100].