Adults who reported declining sleep quality in their 40s and 50s had more beta-amyloid protein in their brains later in life, positron emission tomography brain scans revealed.
In addition, those who reported declining sleep quality in their 50s and 60s had more tau protein tangles in their brain. Both are associated with a higher risk of Alzheimer’s disease.
The findings, published online in The Journal of Neuroscience, demonstrate the importance of sleep for brain health.
“Insufficient sleep across the lifespan is significantly predictive of your development of Alzheimer’s disease pathology in the brain,” said study senior author Matthew Walker, PhD, a sleep researcher and psychology professor at the University of California, Berkeley. “Unfortunately, there is no decade of life that we were able to measure during which you can get away with less sleep. There is no Goldilocks decade during which you can say, ‘This is when I get my chance to short sleep.’”
“The leading hypothesis, the amyloid cascade hypothesis, is that amyloid is what happens first on the path to Alzheimer’s disease,” explained study first author Joseph Winer, a graduate student in the center for sleep science at the University of California, Berkeley. “Then, in the presence of amyloid, tau begins to spread throughout the cortex, and if you have too much of that spread of tau, that can lead to impairment and dementia.”
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The study also used electroencephalogram sleep recordings to evaluate brain rhythms during sleep. People with high levels of tau protein in the brain tended to lack synchronization of brain waves associated with healthy sleep. Researchers believe the impaired electrical sleep signature could act as a novel biomarker for tau protein in the brain.
“Our hope is that, in the future, a small head device could be worn by people at home and provide all the necessary sleep information we’d need to assess these Alzheimer’s disease proteins,” Dr. Walker said. “We may even be able to track the effectiveness of new drugs aimed at combating these brain proteins by assessing sleep.”
In the meantime, Dr. Walker and coauthors recommended healthcare providers ask patients about sleep problems and provide assistance as needed, such as treatment for sleep apnea, cognitive behavioral therapy for insomnia (CBT-I), or simple sleep counseling.
“I think the message is very clear,” Dr. Walker said. “If you are starting to struggle with sleep, then you should go and see your doctor and find ways, such as CBT-I, that can help you improve your sleep. The goal here is to decrease your chances of Alzheimer’s disease.”