MAPT and Cognitive impairment: Concerning the underlying mechanism involved in the longitudinal detrimental effects of sleep quality on memory capacity, it has been proposed that increased sleep fragmentation contributes to the incremental accumulation—from middle age—of pathophysiological biomarkers (Aβ deposition and tau protein) involved in late life cognitive impairment and dementia-associated pathology (Scullin and Bliwise, 2015; Molano et al., 2017).