MAPT and Alzheimer disease: Given that the AD pathognomonic proteins amyloid-β (Aβ) and tau are released after TBI,4 failure to effectively clear them may relate to why TBI is a risk factor for AD and other dementias.5–7 Because glymphatic clearance is greatest during sleep,8 and sleep is known to be profoundly disrupted after TBI, reduced glymphatic clearance may be a mechanism by which impaired sleep contributes to poor TBI recovery.9 This is important because improving sleep after TBI is a feasible therapeutic target.