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Excessive daytime sleepiness linked to increase in Alzheimer’s biomarker

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Poor sleep quality may be early warning of AD

The study by Dr. Carvalho and his colleagues advances the understanding of sleep disturbance as a risk factor for Alzheimer’s disease.

Findings of the study suggest that poor sleep quality may be an early warning sign of AD-related processes, but we advise caution in interpreting the results of this prospective cohort study given that daytime sleepiness was assessed subjectively using the Epworth Sleepiness Scale (ESS), which may reflect declining sleep quality, but is not necessarily a warning sign for impending amyloidosis because of the low specificity of subjective sleepiness and the many underlying causes that could contribute to ESS scores.

Nevertheless, the results hint at a time in the future when sleep dysfunction might be managed with sleep-based interventions that are deployed at the most optimal time to intervene in the beta-amyloid cascade.

Future studies would ideally include other markers of AD progression, such as cortical atrophy, tau deposition, or cardiovascular changes, and better explain a physiologic link between subjective daytime sleepiness and longitudinal change in beta-amyloid.

Joseph R. Winer is with the department of psychology at the University of California, Berkeley, and Bryce A. Mander, PhD, is with the University of California, Irvine. The text above is derived from their editorial appearing in JAMA Neurology (2018 Mar 12. doi: 10.1001/jamaneurol.2018.0005). The authors reported no conflict of interest disclosures related to their editorial contribution.



Elderly individuals who have excessive daytime sleepiness might be more susceptible to accumulation of an Alzheimer’s disease (AD) biomarker, results of a prospective, longitudinal cohort study suggest.

In the study, excessive daytime sleepiness (EDS) was associated with increased accumulation of beta-amyloid, an important biomarker of AD that manifests in early preclinical stages, wrote first author Diego Z. Carvalho, MD, and his colleagues at the Mayo Clinic, Rochester, Minn. The report was published online March 12 in JAMA Neurology.

An elderly man sleeping in a chair. Jupiterimages/Thinkstock
This finding corroborates previous studies showing that EDS is a risk factor for dementia or cognitive decline, the authors said.

“It remains unclear whether EDS is a result of greater sleep instability, synaptic or network overload, or neurodegeneration of wakefulness-promoting centers,” Dr. Carvalho and colleagues wrote in their report. “However, participants with EDS were more vulnerable to AD pathologic processes.”


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