Can poor sleep lead to dementia?

December 10, 2014, American Academy of Neurology
Credit: xiaphias/Wikipedia

People who have sleep apnea or spend less time in deep sleep may be more likely to have changes in the brain that are associated with dementia, according to a new study published in the December 10, 2014, online issue of Neurology, the medical journal of the American Academy of Neurology.

The study found that people who don't have as much oxygen in their blood during sleep, which occurs with sleep apnea and conditions such as emphysema, are more likely to have tiny abnormalities in tissue, called micro infarcts, than people with higher levels of oxygen in the blood. These abnormalities are associated with the development of .

In addition, people who spent less time in , called , were more likely to have loss of than people who spent more time in slow wave sleep. Slow wave sleep is important in processing new memories and remembering facts. People tend to spend less time in slow wave sleep as they age. Loss of brain cells is also associated with Alzheimer's disease and dementia.

For the study, 167 Japanese American men had sleep tests conducted in their homes when they were an average age of 84. All were followed until they died an average of six years later, and autopsies were conducted on their brains to look for micro infarcts, loss of brain cells, the plaques and tangles associated with Alzheimer's disease and Lewy bodies found in Lewy body dementia.

The researchers divided the participants into four groups based on the percentage of time spent with lower than normal blood during sleep, with the lowest group spending 13 percent of their time or less with low oxygen levels and the highest group spending 72 to 99 percent of the night with low oxygen levels. Each group had 41 or 42 men. Of the 41 men in the lowest group, four had micro infarcts in the brain, while 14 of the 42 men in the highest group had the abnormalities, making them nearly four times more likely to have brain damage.

Previous studies have also shown a link between sleep stages and dementia. For this study, the participants were again divided into four groups based on the percentage of the night spent in slow wave sleep. Of the 37 men who spent the least time in slow wave sleep, 17 had brain cell loss, compared to seven of the 38 men who spent the most time in slow wave sleep.

The results remained the same after adjusting for factors such as smoking and body mass index and after excluding participants who had died early in the follow-up period and those who had low scores on cognitive tests at the beginning of the study.

"These findings suggest that low blood oxygen levels and reduced slow wave sleep may contribute to the processes that lead to cognitive decline and dementia," said study author Rebecca P. Gelber, MD, DrPH, of the VA Pacific Islands Health Care System and the Pacific Health Research and Education Institute in Honolulu, Hawaii. "More research is needed to determine how slow wave sleep may play a restorative role in brain function and whether preventing low may reduce the risk of dementia."

Gelber noted that a previous study showed that use of a continuous positive airway pressure machine (CPAP) for obstructive may improve cognition, even after dementia has developed.

There was no association between the sleep measures and the level of plaques and tangles.

Explore further: Sleep disturbance linked to amyloid in brain areas affected by Alzheimer's disease

Related Stories

Sleep disturbance linked to amyloid in brain areas affected by Alzheimer's disease

December 9, 2014
Healthy, elderly research participants who report being more sleepy and less rested have higher levels of amyloid deposition in regions of the brain that are affected in Alzheimer's disease, according to a report presented ...

Self-reported sleep disturbances are linked to higher risk for Alzheimer's disease in men

October 28, 2014
In a new study, researchers from Uppsala University demonstrate that elderly men with self-reported sleep disturbances run a higher risk of developing Alzheimer's disease than men without self-reported sleep disturbances. ...

Can sleep loss affect your brain size?

September 3, 2014
Sleep difficulties may be linked to faster rates of decline in brain volume, according to a study published in the September 3, 2014, online issue of Neurology, the medical journal of the American Academy of Neurology.

Movements help measure child sleep problems

December 3, 2014
New research from the University of Adelaide has helped to shed light on the complexities of child sleep, and could lead to improved diagnosis of children with sleep-related breathing problems.

Little or poor sleep may be associated with worse brain function when aging

June 26, 2014
Research published today in PLOS ONE by researchers at the University of Warwick indicates that sleep problems are associated with worse memory and executive function in older people.

Protein that rouses the brain from sleep may be target for Alzheimer's prevention

November 24, 2014
A protein that stimulates the brain to awaken from sleep may be a target for preventing Alzheimer's disease, a study by researchers at Washington University School of Medicine in St. Louis suggests.

Recommended for you

Rate of dementia on the decline—but beware of growing numbers

April 17, 2018
The good news? The rate of older Americans with dementia is on the decline.

Research offers potential insight into Alzheimer's disease

April 16, 2018
Slightly elevated beta-amyloid levels in the brain are associated with increased activity in certain brain regions, according to a new study from the Center for Vital Longevity (CVL) at The University of Texas at Dallas.

Americans with a college education live longer without dementia and Alzheimer's

April 16, 2018
Education gives people an edge in their later years, helping them to keep dementia at bay and their memories intact, a new USC-led study has found.

Evidence mounts for Alzheimer's, suicide risks among youth in polluted cities

April 13, 2018
A University of Montana researcher and her collaborators have published a new study that reveals increased risks for Alzheimer's and suicide among children and young adults living in polluted megacities.

Improving brain function in Alzheimer's disease mouse model

April 11, 2018
Using two complementary approaches to reduce the deposits of amyloid-beta in the brain rather than either approach alone improved spatial navigation and memory in a mouse model of Alzheimer's disease. These findings suggest ...

Sleepless nights show ties to Alzheimer's risk

April 10, 2018
Even one night of lost sleep may cause the brain to fill with protein chunks that have long been linked to the development of Alzheimer's disease, a new study warns.

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.