Sleep Loss May Be First Symptom Of Alzheimer’s Disease

Sleep loss could be the first sign of future Alzheimer’s Disease (AD), according to a new study from a team at the Washington University School of Medicine in St. Louis. David M. Holtzman, a professor of neurology who is also the study’s senior author, said that the link could provide an important yet easily obtained clue to help predict who will eventually get the disease. The new research, which probably won’t help most of us sleep any easier, was published today in the journal JAMA Neurology.

An earlier study from the same institution showed that a marker for Alzheimer’s disease rises and falls in the spinal fluid in track with the daily sleep cycle. While the brain is resting, the body apparently has a chance to clear out the Alzheimer’s disease marker, keeping the brain healthy and functioning. This cycle is strongest in healthy young people.

However, in older people, who are more prone to sleep disturbances, the marker didn’t seem to clear completely during sleep. The levels of the AD marker stayed closer to level — a danger signal that increased the risk of developing the disease.

According to the researchers, sleep loss and Alzheimer’s disease may work together to form a vicious cycle. Sleep loss can promote the formation of the tangled plaques that form in the brain, leading to AD. But AD can also interfere with the patient’s ability to get a good night’s sleep.

In the newest study, the neurologists studied 141 volunteers, aged 45 to 75 years old, who appeared to be healthy when they were signed up. They were asked to keep a sleep diary, including naps, for two weeks. The doctors also analyzed their spinal fluid for evidence of Alzheimer’s markers.

The result? Volunteers who had the markers for AD stayed in bed just as long as the volunteers who didn’t, but they had more trouble staying and falling asleep, and they had to take more naps.

“When we looked specifically at the worst sleepers…they were more than five times more likely to have preclinical Alzheimer’s disease than good sleepers,” said Dr. Yo-El Ju, first author of the study.

Tossing and turning instead of sleeping is no fun. But now sleep loss is more than a misery. It’s a possible symptom.

[photo courtesy Correogsk and Wikipedia Commons]