Excessive sleepiness in the daytime could be an indicator of Alzheimer’s disease, research from the Mayo Clinic indicates. The study found that daytime drowsiness is associated with amyloid beta plaque buildup. Accumulation of this protein in the brain is a classic sign of Alzheimer’s.
The study was a longitudinal cohort analysis of 283 elderly participants without dementia, selected from the the Mayo Clinic Study of Aging, a longitudinal population-based study in Olmsted County, Minnesota.
Previous studies have shown that individuals with Alzheimer’s disease have a tendency for disrupted sleep, but just what the link is, and whether it is causative, is not clear.
Key Brain Areas
Prashanthi Vemuri, associate professor of radiology at the Mayo Clinic in Rochester, Minn, and her team analysed magnetic resonance imaging brain scans done on the participants. Increased accumulations of amyloid proteins in in the cingulate gyrus and precuneus brain areas were observed.
It is known that sleep is required to clear toxins and beta-amyloid in the brain, Vemuri said, speaking to CNN.
“We also know that beta-amyloid causes sleep disruptions. So, it’s been a chicken and an egg problem. In our study, we wanted to know if excessive daytime sleepiness causes an increase of amyloid over time in people without dementia. And the answer was yes."
In a journal editorial accompanying the paper, Bryce Mander of the University of California, Irvine and Joseph Winer of the University of California, Berkeley, noted that consistent and untreated sleep disturbance seems to help Alzheimer’s progression and it can happen early, before any symptoms are seen.
More Research Needed
This is just one more reason you should talk to your health care provider if you have sleep problems, since many are treatable.
In terms of the potential clinical impact of this work, Winer and Mander write:
“One implication of this study is that self-report of subjective sleepiness may serve as a simple but effective scientific and clinical tool in assessing AD risk.”
Further research needs to be conducted to clarify the findings, as according the study authors, one big limitation of the study is the lack of objective measures to assess sleep disturbance, for example, polysomnography.
The study was supported by grants from the NIH; the Gerald and Henrietta Rauenhorst Foundation; the Alexander Family Alzheimer’s Disease Research Professorship of the Mayo Foundation; the Elsie and Marvin Dekelboum Family Foundation; Schuler Foundation; and the Rochester Epidemiology Project.
Carvalho, DZ, et al.
Association of Excessive Daytime Sleepiness With Longitudinal β-Amyloid Accumulation in Elderly Persons Without Dementia
JAMA Neurology. March 12, 2018. doi:10.1001/jamaneurol.2018.0049
Last Updated on November 11, 2023