Changes in Sleep May be Dementia

Dementia was related to changes in sleep in both mice and people

(RxWiki News) Poor sleep can affect the way the mind works. New research suggests that changes in sleep patterns or quality may be related to dementia.

Two studies, one in mice and one in people, looked at the link between sleeping and dementia.

They found that changes in sleep patterns may be a risk factor or maybe an early sign of dementia.

"Tell your doctor about excessive daytime sleepiness."

Each of the studies looked at the relationship between dementia and sleep differently. Both found that changes in sleep patterns showed up before signs of dementia.

The study in people looked at the risk of developing thinking problems years after asking people about their sleep.

Researchers, led by Isabelle Jaussent, MSc, at the French national research foundation Inserm, asked 4,894 elderly people without dementia if they had trouble falling asleep, staying asleep or poor sleep quality.

They also asked about daytime sleepiness and sleep medications. Daytime sleepiness is thought to be a way to know that a person’s sleep is not good.

They followed up with the people two, four and eight years later. At each follow-up visit, they did a standard test of mental skills and dementia.

People with excessive daytime sleepiness were 1.26 times more likely to show at least a four point drop in their test for thinking skills.

The authors concluded that poor sleep, showing up as daytime sleepiness, may be an early sign of dementia or it may be a risk factor that is involved in the development of dementia.

Using mice, researchers at Washington University School of Medicine in St. Louis, led by Jee Hoon Roh, MD, PhD, looked at how brain changes associated with dementia were linked to sleep.

They used mice that were genetically altered to develop beta amyloid plaques – the brain plaques that are thought to be involved in symptoms of Alzheimer’s Disease.

They found that sleep cycles of these mice were disrupted before any plaques were formed. After plaques formed in the mice brains, the sleep disruptions got even worse.

When they gave mice a chemical to remove the plaques, the mice went back to their normal sleep patterns.

Dr. Roh and colleagues concluded that changes to sleep patterns appear to be related to the other changes that are happening in the brain in the early stages of dementia.

Together, these two studies show that sleep patterns are related to dementia in some way.

However, it is not yet clear if the changes in sleep are an early sign or just a risk factor. More research is needed.

Dr. Roh’s study was published September 5 in Science and Translational Medicine. Jaussent’s study was published September 1 in Sleep. Conflicts of interest and funding information were not provided with the abstracts.

Review Date: 
September 23, 2012