Katherine Ellen Foley, writing in Quartz »

“Sleep disorders and insufficient sleep contribute to Alzheimer’s decades before people develop the disorder,” Ruth Benca, a psychiatrist at the University of California, Irvine, said during a panel on brain health at the summit in Washington, DC.

Benca’s work has tracked the relationship between sleep—particularly the deep sleep known as rapid-eye movement (REM)—and its relationship to developing dementia later in life. In 2017, she and her team published work following healthy individuals with a variant of a gene called APOE that puts them at a higher risk of developing Alzheimer’s. They found that individuals who reported lower-quality sleep tended to have larger buildups of the proteins associated with Alzheimer’s disease, called amyloid and tau, in the fluid surrounding their brains than those who reported sleeping well. It seemed, they thought, that the process of sleep might be clearing some of these buildups.

Subsequent work has backed up that theory. The same year, another study found that among a cohort of adults over 60, those who took longer to enter REM sleep and dreamt less were at an elevated risk of developing dementia. Last year, researchers from the National Institutes of Health in Bethesda, Maryland published the results of a study that found healthy participants who agreed to be woken up hourly for a night (yeesh) had higher levels of amyloid the following day. And earlier this year, a separate group from Washington University School of Medicine found that older adults who got less REM sleep were likely to have higher amounts of tau, too.

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