MAPT and Cognitive impairment: On the other hand, some researchers found no significant association between the severity of stenosis of carotid and intracranial arteries and cognitive impairment (Lopez‐Oloriz et al., 2013), and decreased brain blood flow caused by atherosclerosis might not lead to increased deposition of Aβ and hyperphosphorylation of tau protein (Hansson et al., 2018).