Is REM sleep linked to white matter structure in older adults?

Details

Self-reported sleep abnormalities are increasingly recognized as negatively associated with brain structure and function in older adults. Less is known about how objectively measured sleep relates to brain structure.

To investigate how sleep architecture and quality relate to white matter microstructure, researchers objectively measured sleep at home in 43 cognitively normal older adults. Each participant underwent diffusion tensor imaging (DTI) and a sleep assessment within a six-month period. Participants completed the PSQI, a subjective measure of sleep quality, and used an at-home sleep recorder (Zeo, Inc.) to measure total sleep time (TST), sleep efficiency (SE), and the percentage of time spent in light sleep (LS), deep sleep (DS), and REM sleep (RS).

Using multiple regressions, the researchers predicted fractional anisotropy (FA) and mean diffusivity (MD) of the corpus callosum from total PSQI score, TST, SE, and the percentage of time in each sleep stage, controlling for age and sex. A greater percentage of time in REM sleep was significantly associated with higher FA (β = 0.41, p = 0.007) and lower MD (β = -0.30, p = 0.03). Total PSQI score, TST, SE, and time in light or deep sleep were not significantly associated with FA or MD (p > 0.13).

The researchers concluded that the percentage of time in REM sleep positively predicted white matter microstructure integrity, unlike the amount of light or deep sleep or subjective and objective measures of sleep quality. They said the link between REM sleep and brain health has the potential to improve sleep interventions in older adults.