Individuals who have reduced REM sleep have an increased risk of developing dementia or Alzheimer’s disease.
Sleep disorders and dementia are closely linked. Patients with Alzheimer’s disease often complain of insomnia or drowsiness during the day. As a consequence of the disease, these disorders are also a predictive sign, confirms a new study published in Neurology.
This work from Boston University (United States) shows that disturbances in REM sleep, the privileged period of dreams, are associated with an increased risk of developing Alzheimer’s disease. This phase plays a crucial role in the maturation of the nervous system but also for the storage of memory.
Shortened REM sleep
The researchers obtained this result by drawing on one of the largest and oldest cohorts, known as the Framingham cohorts. In this small town not far from Boston, volunteer residents and their descendants have been followed since 1947.
For the purposes of this work, the sleep of 321 sixty-year-olds was studied with follow-up for 12 years. During these years, 32 people developed dementia, including 24 Alzheimer’s disease.
Researchers found that people diagnosed spent an average of 17% less time in REM sleep than other volunteers. For a 1% reduction in REM sleep, the risk of developing dementia increases by 9%. No other phase of sleep has been associated with an increased risk.
For the authors, this result suggests that REM sleep may be a predictive sign of dementia. “It remains to be seen why shortened REM sleep predicts a greater risk of dementia,” said Dr. Matthew Pase of the Boston University Department of Neurology. By clarifying the role of sleep in triggering the disease, the hope is to identify a mechanism to slow or even prevent its onset. “
The toxicity of sleep deprivation
A mechanism that is starting to be pierced, according to another publication in Neurology. Researchers at Washington University of Medicine (USA) have found that a disrupted night’s sleep is associated with increased levels of beta amyloid in the brains of healthy 50s. The formation of amyloid plaques is responsible, in part, for the development of Alzheimer’s disease.
In addition, a week of insomnia would promote the build-up of the protein Tau, another toxic protein for the brain and linked to Alzheimer’s disease.
“We have shown that a lack of sleep is linked to higher concentrations of two proteins associated with Alzheimer’s disease,” describe the authors. As a result, we believe that chronic sleep deprivation around the age of 50 could increase the risk of developing this disease later in life, ”say the authors.
Not very reassuring results, while two thirds of French people complain of sleep disorders. In 25 years, adults have lost over 18 minutes of sleep, and adolescents almost an hour.
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