Connections between sleep and cognition in older adults.

SUMMARY: Sleep disturbances and cognitive impairment are common in older adults. Mounting evidence points to a potential connection between sleep and cognitive function. Findings from observational studies support a role for sleep disturbances (particularly for sleep duration, sleep fragmentation, and sleep-disordered breathing) in the development of cognitive impairment. Less consistent evidence exists for associations of insomnia and circadian rhythm dysfunction with cognition. These findings suggest that the sleep-wake cycle plays a crucial part in brain ageing, pointing to a potential avenue for improvement of cognitive outcomes in people at risk of cognitive decline and dementia. Several biological mechanisms might underlie the association between sleep and cognition, but these pathways are not completely understood. Future studies that aim to clarify the association between sleep and cognition might help to identify people at risk of cognitive disorders and to facilitate the development of novel therapies to treat and potentially prevent both sleep disturbances and cognitive impairment.