Another study has shown a link between disrupted sleep patterns and Alzheimer’s disease.
Researchers at Washington University looked at 32 people who have what’s known as “preclinical” Alzheimer’s disease. They have a marker in their spinal fluid associated with Alzheimer’s, but they still don’t have any symptoms of dementia.
Wash U neurologist and sleep specialist Yo-El Ju says when she and her colleagues compared those people to 110 healthy controls, they found the two groups slept about the same amount.
But the people with preclinical Alzheimer’s were more restless: they spent a slightly higher percentage of their time in bed unable to fall asleep.
Ju says they also tended to nap more often during the day.
“About a third of the people with preclinical Alzheimer’s disease were frequent nappers, and about a sixth of people without preclinical Alzheimer’s disease were frequent nappers,” Ju says. “And so it may be that frequent napping also represents a disregulation of their sleep-wake mechanisms.”
In this study, “frequent nappers” were defined as those people who took naps on three or more days per week.
Sleeping problems like insomnia or inadvertent napping are common in people with Alzheimer’s disease, once they start showing symptoms of cognitive decline.
But Ju says it’s too soon to say whether poor sleep also contributes to causing Alzheimer’s.
She says even so, people should pay more attention to their sleeping habits. “I think a lot of times sleep ends up being the last priority on our list after work and family and social life and so on, and perhaps that’s not very healthy,” Ju says.
Previous research on mice has linked sleep deprivation to a build-up of the amyloid brain plaques associated with Alzheimer’s.
The current study is published in the journal JAMA Neurology.
In the U.S., about one out of eight people over age 65 are known to have Alzheimer’s disease.
Follow Véronique LaCapra on Twitter: @KWMUScience