Relationships between sleep stages and changes in cognitive function in older men: the MrOS Sleep Study

Area of Science:

• Gerontology
• Sleep Medicine
• Cognitive Neuroscience

Background:

• Cognitive decline is a significant concern in aging populations.
• Sleep disturbances are increasingly recognized as potential contributors to cognitive impairment.
• Understanding the specific associations between sleep stages and cognitive trajectories is crucial for developing targeted interventions.

Purpose of the Study:

• To examine the relationship between specific sleep stage distributions and the progression of cognitive decline in elderly men.
• To identify sleep stage patterns that may predict future cognitive impairment in older male populations.

Main Methods:

• A prospective, population-based substudy involving 2,601 community-dwelling men aged 67 years and older.
• In-home polysomnography was used to assess sleep stages at baseline.
• Cognitive function was evaluated using the Trail Making Test Part B and the Modified Mini-Mental State Examination (3MS) at baseline and two follow-up visits over an average of 3.4 years.

Main Results:

• Higher percentages of sleep time in Stage N1 were associated with a twofold increase in cognitive decline for both cognitive tests.
• Lower percentages of sleep time in Stage R were significantly linked to greater cognitive decline on the 3MS.
• These associations remained consistent after adjusting for total sleep time and sleep-disordered breathing; no significant links were found for Stages N2 or N3.

Conclusions:

• Increased time spent in Stage N1 sleep and reduced time in Stage R sleep are associated with accelerated cognitive decline in older men.
• These findings highlight the potential role of specific sleep architecture alterations in the pathogenesis of cognitive impairment in aging men.