Rapid eye movement (REM) sleep is markedly altered in Alzheimer’s disease (AD), and its reduction in older populations is associated with AD risk. However, little is known about the underlying brain mechanisms. Within this framework, a recent study published by André and collaborators (https://doi.org/10.1002/ana.26604) investigated the relationships between REM sleep integrity and amyloid deposition, gray matter volume, and perfusion in aging.
One-hundred and twenty-one cognitively unimpaired older adults, who underwent a polysomnography, T1-weighted magnetic resonance imaging, early and late Florbetapir positron emission tomography scans to evaluate gray matter volume, perfusion, and amyloid deposition were included. Indices reflecting REM sleep macro- and microstructural integrity (ie, normalized electroencephalographic spectral power values) were used for multiple regression analyses to check for significant correlations.
Lower perfusion in frontal, anterior and posterior cingulate, and precuneus areas was associated with decreased delta power and electroencephalographic slowing (slow/fast frequencies ratio), and increased alpha and beta power. To a lower extent, similar results were obtained between gray matter volume and delta, alpha, and beta power. In addition, lower REM sleep theta power was more marginally associated with greater diffuse amyloid deposition and lower gray matter volume in fronto-temporal and parieto-occipital areas.
These results suggest that alterations of REM sleep microstructure are associated with greater neurodegeneration and neocortical amyloid deposition in older adults. Further studies are warranted to replicate these findings and determine whether older adults exhibiting REM sleep alterations are more at risk of cognitive decline and belonging to the Alzheimer’s continuum.
Key Points:
- In cognitively uninpaired elderly people there is a significant association between reduced REM sleep and increased amyloid-beta deposition.
- The association between reduced REM sleep and amyloid-beta deposition was stronger in individuals with the ApoE4 gene, a known risk factor for Alzheimer's disease.
- Targeting sleep disturbances, specifically REM sleep, may be a potential therapeutic approach for preventing or delaying the onset of Alzheimer's disease.
- There is need for further research to elucidate the complex relationship between sleep and Alzheimer's disease.
References:
- André C, Champetier P, Rehel S, Kuhn E, Touron E, Ourry V, Landeau B, Le Du G, Mézenge F, Segobin S, de la Sayette V, Vivien D, Chételat G, Rauchs G; Medit-Ageing Research Group. Rapid Eye Movement Sleep, Neurodegeneration, and Amyloid Deposition in Aging. Ann Neurol. 2023 Jan 15. doi: 10.1002/ana.26604. Epub ahead of print. PMID: 36641644.
- 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 Mar 1;38(3):411-21. doi: 10.5665/sleep.4500. PMID: 25325465; PMCID: PMC4335525.
- Winer JR, Mander BA, Kumar S, Reed M, Baker SL, Jagust WJ, Walker MP. Sleep Disturbance Forecasts β-Amyloid Accumulation across Subsequent Years. Curr Biol. 2020 Nov 2;30(21):4291-4298.e3. doi: 10.1016/j.cub.2020.08.017. Epub 2020 Sep 3. PMID: 32888482; PMCID: PMC7642104.
Publish on behalf of the Scientific Panel on Sleep-wake disorders