Sleep is essential to health but findings of a new study suggest that prolonged sleeping may also indicate dementia.


Dementia is a condition marked by loss of memory and other mental abilities grave enough to interfere with daily life. The condition is caused by physical changes in the brain. The most common type of dementia is Alzheimer's disease, which accounts for 60 to 80 percent of all dementia cases.

Prolonged Sleeping And Dementia

In a new study published in the journal Neurology, Matthew Pase, from the Boston University School of Medicine, and colleagues followed a group of adults for a period of 10 years and asked them how long they typically sleep at night to examine the link between sleep duration and the likelihood of developing dementia.

Although the researchers did not find a heightened dementia risk for individuals who had been sleeping for nine hours or more a night for more than 13 years, they noticed an increased risk for those who recently started to sleep for more than nine hours.

The researchers found that new long-sleepers have an increased likelihood of developing dementia. Those who recently started to sleep for more than nine hours were found to have a 20 percent increased likelihood of being diagnosed with the neurological condition. They also appeared to have smaller brain volumes.

Pase and colleagues said that longer sleep is not a direct cause of dementia but rather a sign that could indicate chemical changes that happen in the brain. It is also possible that the development of dementia can make people feel more tired.

Based on their findings, the researchers said that self-reported sleep duration may serve as a useful clinical tool that can help predict individuals who are at risk of developing dementia within 10 years.

"Screening for sleeping problems may aid in the early detection of cognitive impairment and dementia. Older persons recently reporting becoming excessive sleepers who also complain of problems with thinking or memory may warrant assessment and monitoring," Pase said.

While recent prolonged sleep among older individuals may indicate a heightened risk for dementia, earlier studies have also identified other warning signs of the disease.

Sudden Changes In Personality And Behavior

A 2016 study, for instance, found that sudden and long-time changes in a person's mood, behavior, and personality may also serve as an early sign of Alzheimer' disease.

Nina Silverberg, from the Alzheimer's disease program of the National Institute of Aging, said that while Alzheimer's disease is primarily considered to be a memory disorder, years of research show it can also start as a behavioral issue.

Delirium After Surgery

Another study also found evidence that delirium after surgery among older patients may be associated with long-term cognitive decline, which is considered as a marker for Alzheimer's disease.


Physical conditions may likewise indicate increased risk for dementia. In one study, individuals who had been diagnosed by a hospital dermatologist for rosacea had a 42 percent higher risk for dementia. Rosacea is a skin disease characterized by severe redness and blushing of the skin, often on the face.

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