Later-life sleep, cognition, and neuroimaging research: an update for 2020.

This review summarizes recent studies of sleep and brain health in later life, focusing on cognitive and magnetic resonance imaging (MRI)-derived outcomes. The majority of older people report sleep problems, and over one-third have sleep-disordered breathing (SDB). The research described herein builds on work demonstrating that abnormal sleep duration, sleep fragmentation, and SDB are associated with memory impairment and executive dysfunction. Self-reported short sleep is linked with greater cortical thinning and lower white matter integrity, and objectively measured fragmentation and SDB are tied to gray matter atrophy and altered connectivity. Results suggest that brain changes mediate previously identified sleep-cognition associations. Additional clinical trials are needed to determine whether treating insomnia or SDB benefits cognition in this population.