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Sleepless Nights and Dementia: Research Finds a Link

If you’re among the one-third of American adults who don’t get enough sleep, research suggests it would be wise to change course. Three important studies have found a possible link between lack of sleep and dementia (including Alzheimer’s disease), as well as a decline in cognitive skills like reading, remembering and reasoning. Here’s a recap of the studies:

At the Boston University School of Medicine, researchers found that people who spent less time in the rapid eye movement (REM) sleep stage had a greater risk of developing dementia. REM is the sleep stage when dreaming occurs. The first REM stage occurs about an hour to an hour-and-a-half into sleep and then recurs multiple times throughout the night as sleep cycles repeat.

Overall, the scientists determined that REM sleep is a predictor of dementia, and that more research is needed to clarify the role of sleep in the onset of dementia. Their hope is to eventually identify ways to intervene so that dementia can be delayed or even prevented.

No link was found between dementia and other stages of sleep.

Scientists say their concern is with people who suffer from chronic sleep problems.

At UC Berkeley, researchers found that beta-amyloid — a protein that has long been suspected of promoting Alzheimer’s — collects in higher concentrations in the brains of people who suffer from consistently poor sleep. As deposits of beta-amyloid in the brain increase, it disrupts sleep, which feeds into a miserable cycle that may lead to dementia.

By examining brain scans throughout the study period, researchers found that the people with the highest concentration of beta-amyloid in their brains experienced the worst sleep, and they performed poorly on word recall tests. They concluded that beta-amyloid has a direct impact on memory by ruining the sleep required for building memories.

At the Washington University School of Medicine in St. Louis, scientists knew that during quality sleep the brain rids itself of unneeded beta-amyloid. But when a person is unable to sleep, the brain is unable to dispose of unneeded beta-amyloid and instead produces more of it. Over time, the excess protein collects into plaque, the same plaque found dotted throughout the brains of people with Alzheimer’s disease.

Specifically, beta-amyloid levels in sleep-deprived people were 25 to 30 percent higher than in those who had slept through the night. After a sleepless night, beta-amyloid levels were on par with the levels seen in people genetically predisposed to develop Alzheimer’s at a young age.

If you were prone to all-nighters in your college days, that doesn’t mean you should be worried. Scientists say their concern is with people who suffer from chronic sleep problems.

Is There a Solution?

You might be wondering if there’s a way to reduce or treat a build-up of beta-amyloid in the brain of someone with dementia. Attempts to do so have not successfully improved dementia. One researcher compared the attempt to an earthquake: You can clear the rubble after the quake, but the damage from the quake remains.

The good news is that the build-up of beta-amyloid in healthy adults begins long before the onset of symptoms of dementia. This leaves hope that if beta-amyloid can be detected early through screening, and then treated, it might be possible to delay the onset of more severe symptoms of dementia.

In the meantime, researchers suggest that people who have trouble getting quality sleep may find that regular exercise helps. They caution that sleeping pills could worsen the problem.

Source: Boston University School of Medicine; Cal Alumni Association/UC Berkeley; Washington University; National Institutes of Health; American Academy of Neurology; Centers for Disease Control and Prevention