Sleep loss precedes Alzheimer's symptoms

March 11, 2013

Sleep is disrupted in people who likely have early Alzheimer's disease but do not yet have the memory loss or other cognitive problems characteristic of full-blown disease, researchers at Washington University School of Medicine in St. Louis report March 11 in JAMA Neurology.

The finding confirms earlier observations by some of the same researchers. Those studies showed a link in mice between and , a hallmark of Alzheimer's disease. Early evidence tentatively suggests the connection may work in both directions: Alzheimer's plaques disrupt sleep, and promotes Alzheimer's plaques.

"This link may provide us with an easily detectable sign of Alzheimer's pathology," says senior author David M. Holtzman, MD, the Andrew B. and Gretchen P. Jones Professor and head of Washington University's Department of Neurology. "As we start to treat people who have markers of early Alzheimer's, changes in sleep in response to treatments may serve as an indicator of whether the new treatments are succeeding."

are common in people who have symptomatic Alzheimer's disease, but scientists recently have begun to suspect that they also may be an indicator of early disease. The new paper is among the first to connect early Alzheimer's disease and sleep disruption in humans.

For the new study, researchers recruited 145 volunteers from the University's Charles F. and Joanne Knight Alzheimer's Disease Research Center. All of the volunteers were 45 to 75 years old and cognitively normal when they enrolled.

As a part of other research at the center, scientists already had analyzed samples of the volunteers' spinal fluids for markers of Alzheimer's disease. The samples showed that 32 participants had preclinical Alzheimer's disease, meaning they were likely to have present in their brains but were not yet cognitively impaired.

Participants kept daily sleep diaries for two weeks, noting the time they went to bed and got up, the number of naps taken on the previous day, and other sleep-related information.

The researchers tracked the participants' activity levels using sensors worn on the wrist that detected the wearer's movements.

"Most people don't move when they're 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 , 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."

Explore further: Trouble sleeping? It may affect your memory later on

More information: 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.

Related Stories

Trouble sleeping? It may affect your memory later on

February 14, 2012
The amount and quality of sleep you get at night may affect your memory later in life, according to research that was released today and will be presented at the American Academy of Neurology's 64th Annual Meeting in New ...

Sleep problems may be early sign of Alzheimer's

September 5, 2012
Sleep disruptions may be among the earliest indicators of Alzheimer's disease, scientists at Washington University School of Medicine in St. Louis report Sept. 5 in Science Translational Medicine.

Falls may be early sign of Alzheimer's

July 18, 2011
Falls and balance problems may be early indicators of Alzheimer’s disease, researchers at Washington University School of Medicine in St. Louis report July 17, 2011, at the Alzheimer’s Association International ...

Marker for Alzheimer's disease rises during day and falls with sleep

September 26, 2011
A marker for Alzheimer's disease rises and falls in the spinal fluid in a daily pattern that echoes the sleep cycle, researchers at Washington University School of Medicine in St. Louis have found.

Recommended for you

Noninvasive eye scan could detect key signs of Alzheimer's years before patients show symptoms

August 17, 2017
Cedars-Sinai neuroscience investigators have found that Alzheimer's disease affects the retina—the back of the eye—similarly to the way it affects the brain. The study also revealed that an investigational, noninvasive ...

Could olfactory loss point to Alzheimer's disease?

August 16, 2017
By the time you start losing your memory, it's almost too late. That's because the damage to your brain associated with Alzheimer's disease (AD) may already have been going on for as long as twenty years. Which is why there ...

New Machine Learning program shows promise for early Alzheimer's diagnosis

August 15, 2017
A new machine learning program developed by researchers at Case Western Reserve University appears to outperform other methods for diagnosing Alzheimer's disease before symptoms begin to interfere with every day living, initial ...

Brain scan study adds to evidence that lower brain serotonin levels are linked to dementia

August 14, 2017
In a study looking at brain scans of people with mild loss of thought and memory ability, Johns Hopkins researchers report evidence of lower levels of the serotonin transporter—a natural brain chemical that regulates mood, ...

Alzheimer's risk linked to energy shortage in brain's immune cells

August 14, 2017
People with specific mutations in the gene TREM2 are three times more likely to develop Alzheimer's disease than those who carry more common variants of the gene. But until now, scientists had no explanation for the link.

Scientists reveal role for lysosome transport in Alzheimer's disease progression

August 7, 2017
Researchers from Yale University School of Medicine have discovered that defects in the transport of lysosomes within neurons promote the buildup of protein aggregates in the brains of mice with Alzheimer's disease. The study, ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.