Sleep stage distribution of increased time in stage N1 sleep and less time in REM sleep is associated with declining cognitive function in older men, according to a study of 2,601 community-dwelling men ages 67 years and older.
Investigators assessed cognitive outcomes using the Trail Making Test Part B and Modified Mini-Mental State (3MS) at the initial visit, which also included in-home polysomnography, and 2 follow-up visits. Subjects were stratified by quartiles of percentage of sleep time spent in different sleep stages, which resulted in:
• the highest quartile of stage N1 sleep had double the risk of cognitive decline compared with those in the lowest quartile
• the lowest quartile of REM stage had more cognitive decline on the 3MS than those in the highest quartile
Citation: Song Y, Blackwell T, Yaffe K, Ancoli-Israel S, Redline S, Stone KL; Osteoporotic Fractures in Men (MrOS) Study Group. Relationships between sleep stages and changes in cognitive function in older men: The MrOS Sleep Study. Sleep. 2015;38(3):411-421. doi: 10.5665/sleep.4500.