Sleep Loss Precedes Alzheimer's Symptoms: Page 2 of 2
asleep, and we developed a way to use the data we collected as a marker for whether a person was asleep or awake," says first author Yo-El Ju, MD, assistant professor of neurology. "This let us assess sleep efficiency, which is a measure of how much time in bed is spent asleep."
Participants who had preclinical Alzheimer's disease had poorer sleep efficiency (80.4 percent) than people without markers of Alzheimer's (83.7 percent). On average, those with preclinical disease were in bed as long as other participants, but they spent less time asleep. They also napped more often.
"When we looked specifically at the worst sleepers, those with a sleep efficiency lower than 75 percent, they were more than five times more likely to have preclinical Alzheimer's disease than good sleepers," Ju says.
Ju and her colleagues are following up with studies in younger participants who have sleep disorders.
"We think this may help us get a better feel for the way this connection flows — does sleep loss drive Alzheimer's, does Alzheimer's lead to sleep loss, or is it a combination?" Ju says. "That will help us determine whether we can change the course of disease with pharmaceuticals or other treatments."
This study was funded by an Ellison Medical Foundation Senior Scholar award and NIH grant P01NS074969 from the National Institute of Neurological Disorders and Stroke.
Ju Y-E S, McLeland JS, Toedebusch CD, Xiong C, Fagan AM, Duntley SP, Morris JC, Holtzman DM. Sleep quality and preclinical Alzheimer disease. JAMA Neurology , online March 11.