18 July 2012

Can sleep help to predict dementia?

Presented at the Alzheimer’s Association International Conference in Vancouver, studies have found another possible way to predict the onset of dementia in later life. Neurologists are now saying that too much or too little sleep could be an early warning sign of Alzheimer’s, the most common form of dementia.

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French researchers conducted tests on 5,000 over 65’s and discovered that the fifth who regularly took a nap did not perform as well as the rest of the group in cognitive tests. Dr Claudine Berr, from the Institut National de la Santé et de la Recherche Médical (Inserm), told the audience, “These results suggest that excessive daytime sleepiness may be an early predictor of cognitive decline.”

Also presented at the conference, Elizabeth Devore from Brigham and Women’s Hospital in Boston, Massachusetts, found that regularly sleeping over 9 hours a night and less than 5 hours could result in lower mental ability. Devore studied 15,000 former nurses over 70 and found that participants who had too much or too little sleep exhibited chemical brain changes, which can indicate early Alzheimer’s.

Dr Marie Janson of Alzheimer’s Research UK said, “There is already some evidence linking sleep duration and disturbances to cardiovascular health and diabetes, so it’s not surprising to see studies examining how sleep might affect cognitive ability over time. We can already help people to achieve the recommended seven hours, so regulating sleep could become a strategy to protect against cognitive decline if further evidence bears this out.”