Brainwashing: Quality sleep today can reduce risk of dementia later

Texas A&M University College of Dentistry, in collaboration with the University of Texas at Dallas and the Center for BrainHealth, recently investigated the possible link between sleep apnea and the risk of Alzheimer’s disease.

In a pilot study published in Geriatrics, researchers derived data by analyzing the sleep patterns of participants over the course of a month. They focused on sleep apnea, a condition in which the upper airway repeatedly collapses, disrupting breathing and causing frequent awakening during the night.

Emet Schneiderman, professor of biomedical sciences at the College of Dentistry and co-author of the study, reports that six of the 18 study participants had Alzheimer’s disease, seven had mild cognitive impairment and five were cognitively normal. All ranged from 50 to 85 years old and had a history of snoring.

“We see that an awful lot of these people who develop Alzheimer’s have had sleep issues for decades beforehand,” Schneiderman said. “We think that sleep, healthy sleep, stable sleep plays a very important role in housekeeping of the brain and keeping it healthy.”

During the night people typically go through about four to six sleep cycles, and each cycle ends with rapid eye movement (REM) sleep. REM sleep is when people dream and the person’s brain and eyes are very active while the rest of the body remains asleep. REM sleep is important for consolidating memories. However, Schneiderman says it is the sleep beforehand that is also important. During that very deep part of the sleep cycle, the brain does its “housekeeping.”

“Everything slows down in the brain except for what’s called cerebrospinal fluid flow,” He said. “It’s basically a fluid that bathes the brain. Throughout the day the brain produces all kinds of waste products. During that really deep sleep, the fluid cleans that stuff out and keeps the brain healthy. If we don’t get good, deep sleep, the waste in the brain accumulates. What you see in older people with Alzheimer’s is accumulations of plaques and tangles made up of those toxic proteins.”

Thus, in addition to causing symptoms such as snoring and tiredness during the day, sleep apnea interrupts the cleansing of the brain.

The researchers learned that the maximum breathing rate during uninterrupted sleep can reveal the difference between healthy people and those with cognitive impairment or Alzheimer’s. They also determined that the myTAP device—a specialized appliance that snaps into the mouth to prevent snoring—can improve a person’s breathing rate and cognitive function. Researchers noted improvement in a majority of the patients with mild cognitive impairment (71 percent) but in only half of the patients with Alzheimer’s. This potentially shows that early intervention can help keep mild impairment from developing into more serious forms of dementia.