Sleep, 24-Hour Activity Rhythms, and Cognitive Reserve: A Population-Based Study.

Area of Science:

• Neuroscience
• Gerontology
• Sleep Medicine

Background:

• Cognitive reserve hypothesis explains individual differences in dementia susceptibility.
• Poor subjective sleep has been previously linked to lower cognitive reserve.

Purpose of the Study:

• To investigate the association between actigraphy-measured sleep and 24-hour activity rhythms with cognitive reserve.

Main Methods:

• 1,002 participants from the Rotterdam Study underwent actigraphy, cognitive testing, and brain MRI.
• Sleep and activity rhythms were measured via actigraphy over a mean of 6.7 days.
• Cognitive reserve was modeled as a latent variable adjusted for demographic and neuroimaging factors.

Main Results:

• Longer sleep onset latency and lower sleep efficiency were associated with lower cognitive reserve.
• After adjustment, only longer sleep onset latency remained significantly associated with lower cognitive reserve.
• No significant association was found between 24-hour activity rhythm and cognitive reserve.

Conclusions:

• Longer sleep onset latency is particularly associated with reduced cognitive reserve.
• Further longitudinal research is needed to determine if improving sleep onset latency can enhance cognitive reserve.
• This research may inform strategies to mitigate dementia risk by targeting sleep quality.