Association of excessive daytime sleepiness in older adults and biomarker of Alzheimer's disease

Bottom Line: Excessive daytime sleepiness in a group of older adults without dementia was associated with increased accumulation of a brain protein that is an important biomarker for Alzheimer disease.

Why The Research Is Interesting: Accumulation of the protein β-amyloid (Αβ) manifests early in the preclinical stages of Alzheimer and is an important biomarker of the disease. Sleep may help to clear soluble Αβ and disturbed sleep may aid in its accumulation. Disrupted sleep can also increase synaptic activity in the brain, which may contribute to Αβ accumulation. Identifying whether excessive daytime sleepiness is associated with Αβ accumulation could be important for developing interventions.

Who and When: 283 participants 70 or older without dementia from the Mayo Clinic Study of Aging who completed surveys assessing sleepiness at baseline and had at least two consecutive imaging scans of their brains from 2009 to 2016

What (Study Measures): Self-reported excessive daytime sleepiness; difference in Αβ levels between two scans in different regions of the brain

How (Study Design): This was an observational study. Researchers were not intervening for purposes of the study and cannot control for all the natural differences that could explain the study results.

Authors: Prashanthi Vemuri, Ph.D., of the Mayo Clinic, Rochester, Minnesota, and coauthors

Results: 63 participants (22.3 percent) had excessive daytime sleepiness (EDS) at baseline; excessive daytime sleepiness was associated with increased Αβ accumulation in susceptible regions of the brain

Study Limitations: The study lacked objective measures of sleep disturbance and the assessment of reduced sleep didn't quantify the amount of sleep time.

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Related Material: The editorial, "Waking Up to the Importance of Sleep in the Pathogenesits of Alzheimer Disease," by Joseph R. Winer, M.A., of the University of California, Berkeley, and Bryce A. Mander, Ph.D., of the University of California, Irvine, also is available on the For The Media website.

To read the full study, please visit the For The Media website.

(doi:10.1001/jamaneurol.2018.0049)

Editor's Note: The article contains conflict of interest and funding/support disclosures. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.

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