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Alzheimer’s biomarker linked to poor sleep quality

Amyloid plaque deposition, the pathologic hallmark of Alzheimer’s disease, was associated with poor sleep quality, but not changes in sleep quantity, new data suggest.

“Sleep-wake problems are common in Alzheimer’s disease,” researchers wrote. “Brain regions and pathways important for sleep and wake mechanisms are affected early in [Alzheimer’s disease].”

Yo-El S.Ju, MD, of the department of neurology at The Charles F. and Joanne Knight Alzheimer’s Disease Center at the University of Washington, and colleagues examined whether amyloid plaque deposits in preclinical Alzheimer’s disease — detected before the onset of cognitive impairment — was associated with changes in sleep quality or quantity in 145 participants with healthy cognition aged 45 to 75 years. The researchers assessed sleep for 2 weeks using actigraphy, and the presence of amyloid plaque was determined from cerebrospinal fluid samples.

Amyloid plaque deposition was identified in 32 (22.5%) patients. Even after controlling for age, sex and the expression of the apolipoprotein E gene, these patients had worse sleep quality vs. those without amyloid (80.4% vs. 83.7%; P=.04). However, sleep quantity — measured by total sleep time — did not differ significantly between those with or without amyloid. Amyloid was also associated with frequent napping 3 or more days per week (31.2% vs. 14.7%; P=.03).

“Our data provide impetus for important future studies,” the researchers wrote. “Longitudinal follow-up with ongoing measurements of amyloid and sleep (as measured by electroencephalography) should enable us to begin to tease apart the details of the abnormalities in sleep that begin to occur with the onset of [Alzheimer’s disease] pathology as well as the directionality of the relationship between sleep and amyloid deposition.”

Disclosure: Study researcher Stephen P. Duntley, MD, reports financial relationships with UCB and Jazz Pharmaceuticals. Study researcher John C. Morris, MD, reports financial relationships with Janssen, Pfizer, Avid Radiopharmaceuticals, Eisai, Esteve, GlaxoSmithKline and Novartis.