Antemortem behavioral testing and postmortem histopathological assessment (of frontal and temporal cortex) in patients with either no cognitive impairment, preclinical AD, mild cognitive impairment, early AD, or mild-to-moderate AD, confirmed elevation of p47phox, p67phox, p40phox and p22phox, as well as elevation of NOX activity in mild cognitive impairment and AD patients [197]. This evidence concerns the gene NCF4 and Cognitive impairment.