Relationships between sleep quality and brain volume, metabolism and amyloid deposition in late adulthood.
Résumé
Recent studies in mouse models of Alzheimer’s disease (AD) and in humans suggest that sleep disruption and amyloid-beta (Aβ) accumulation are interrelated, and may thus exacerbate each other. We investigated the association between self-reported sleep variables and neuroimaging data in 51 healthy older adults. Participants completed a questionnaire assessing sleep quality and quantity, and underwent positron emission tomography scans using [18F]florbetapir and [18F]fluorodeoxyglucose, and an MRI scan to measure Aβ burden, hypometabolism, and atrophy, respectively. Longer sleep latency was associated with greater Aβ burden in prefrontal areas. Moreover, the number of nocturnal awakenings was negatively correlated with gray matter volume in the insular region. In asymptomatic middle-aged and older adults, lower self-reported sleep quality was associated with greater Aβ burden and lower volume in brain areas relevant in ageing and AD, but not with glucose metabolism. These results highlight the potential relevance of preserving sleep quality in older adults, and suggest that sleep may be a factor to screen for in individuals at risk for AD.