Sleep characteristics and brain structure: A systematic review with meta-analysis.

Area of Science:

• Neuroscience
• Sleep Science
• Gerontology

Background:

• Aging populations face increasing neurodegenerative diseases and dementia.
• Sleep is vital for brain health, homeostasis, and repair.
• Impaired sleep may increase neurodegeneration risk, but its link to brain structure in healthy adults is unclear.

Purpose of the Study:

• To systematically review and analyze the literature on sleep characteristics and disorders in relation to brain structure in healthy adults.

Main Methods:

• Systematic literature search across major databases (PubMed, MEDLINE, Scopus, etc.).
• Inclusion of empirical studies on healthy adults examining sleep-brain structure associations.
• Meta-analysis of volumetric data and seed-based spatial analysis of voxel-based morphometry (VBM) studies.

Main Results:

• 106 studies with 108,364 participants were included.
• Most studies (73.1%) reported associations between sleep issues and lower brain volumes.
• REM sleep behavior disorder specifically linked to reduced grey matter in the right frontal gyrus.

Conclusions:

• Poor sleep quality, short/long sleep duration, and sleep disorders are predominantly associated with reduced brain volumes.
• Inadequate sleep may be a contributing factor to neurodegeneration.
• Monitoring and managing sleep health is crucial for preventing or mitigating neurodegenerative processes.