Excessive daytime sleepiness can lead to dementia, study indicates

NEW YORK, Nov. 6 (UPI) - Experiencing excessive daytime sleepiness as an older adult can spell dire consequences that ultimately may lead to full-blown dementia, according to a new study funded by the National Institute on Aging.

The study was published online Wednesday in Neurology, the medical journal of the American Academy of Neurology.

Sleep dysfunction raises the risk of motoric cognitive risk syndrome, a type of predementia that can progress to dementia, researchers found.

They emphasized the importance of screening and early intervention for sleep disturbance as a potential strategy to prevent cognitive decline in a rapidly aging global population.

While people with this syndrome exhibit a slow gait and some memory issues, they initially don't have mobility issues or dementia.

The study "reinforces the hypothesis of a link between sleep-related issues - more specifically daytime sleepiness - and further cognitive impairment in older adults," corresponding author Dr. Victoire Leroy, told UPI.

"Our findings suggest also how precious sleep is. When it causes unusual sleepiness during our days, we should rethink our habits to best protect our brain," said Leroy, who conducted the research as a former postdoctoral fellow in the neurology department at Albert Einstein College of Medicine in the Bronx, N.Y.

She is now an assistant professor in the geriatrics department at Tours University Hospital in Tours, France.

Among older individuals suffering from excessive daytime sleepiness and lacking enthusiasm, 35.5% developed the syndrome, compared to 6.7% of people without these issues, the study found

Researchers adjusted for variables that could influence risk of the syndrome, such as age, depression and other health conditions. Even then, they determined that people with excessive daytime sleepiness and a dearth of enthusiasm for activities had more than a threefold chance of developing the syndrome than those without those sleep-related problems.

The risk of developing this syndrome was greater regardless of whether older people had depressive symptoms, researchers pointed out.

Their study included 445 people, averaging 76 years old, without dementia. At the outset, 42 people had motoric cognitive risk syndrome. Another 36 people developed it during the research.

From the beginning, researchers asked participants about memory issues and tested walking speed on a treadmill. They retested the participants once a year for an average of three years.

The sleep assessment asked how frequently people had trouble sleeping because they wake up in the middle of the night, can't fall asleep within 30 minutes, feel too hot or cold, and take medicine to help them sleep.

To evaluate excessive daytime sleepiness, researchers inquired how often people have experienced difficulty staying awake while driving, eating meals or engaging in social activity. The question about enthusiasm asked how much of a problem people have had maintaining an adequate amount to accomplish tasks.

Researchers acknowledged a limitation of the study in that participants reported their own information about sleep, so their recall may not have been accurate.

Other experts reinforced the importance sleep plays in everyone's life.

"This study is in line with previous evidence indicating an association between difficulty with sleep and cognitive decline," said Dr. Gholam Motamedi, a neurologist at MedStar Georgetown University Hospital in Washington, D.C. He was not involved in the study.

"I think such studies increase the awareness, both in the medical community as well as the public,about the importance of sleep and proper workup and management as early as possible to minimize the risk of future dementia, Motamedi said.

It's essential to promote sleep quality as part of overall health, said Dr. Alla Al-Habib, a neurologist at Texas Health Presbyterian Hospital Plano in Plano, Texas.

"Prioritizing sleep hygiene practices, such as maintaining a regular sleep schedule, meditation and limiting screen time before bed could be helpful," Al-Habib said.

But it's also vital to tell healthcare providers about symptoms of excessive daytime sleepiness or low energy. They can screen for sleep disturbances by asking if the patient feels refreshed upon waking up and if the patient naps during the day, she said.

During this screening, she added, clinicians also should evaluate for depression, discuss physical activity, suggest improvements in diet and lifestyle, and address chronic diseases.

"Sleep plays a critical role in cognitive decline and dementia. Don't take your sleep lightly," said Karen Lincoln, a professor and director of the Center for Environmental Health Disparities Research at the University of California-Irvine.

In 2022, she launched the "BrainWorks 2.0: Sleep Tight" study, using neuroimaging to better understand how sleep quality impacts the brain's clearance system - a potential predictor of Alzheimer's disease.

"If you think you're sleeping too much or not enough, if you wake up and have a difficulty falling back asleep, or if you're falling asleep during the day or at times when you should be awake, you might consider getting assessed for a sleep disorder regardless of your age," Lincoln said.

"Good sleep hygiene and treatment for sleep disturbances can lower your risk for dementia," she said.