Acting out dreams could be a sign of the second most common kind of dementia among the elderly, a small new study suggests.
Researchers from the Mayo Clinic found that when a man has a risk factor for dementia with Lewy bodies (such as hallucinations or cognitive problems) in addition to REM sleep behavior disorder, he is five times more likely to have the dementia. REM sleep behavior disorder is when the brain is in REM sleep but the body acts out dreams in the form of kicking, jumping, etc.
"While it is, of course, true that not everyone who has this sleep disorder develops dementia with Lewy bodies, as many as 75 to 80 percent of men with dementia with Lewy bodies in our Mayo database did experience REM sleep behavior disorder. So it is a very powerful marker for the disease," study researcher Melissa Murray, Ph.D., a neuroscientist at Mayo Clinic, said in a statement.
Symptoms of dementia with Lewy bodies are often similar to Parkinson's disease and Alzheimer's, in that they include visual hallucinations, motor problems and cognitive problems, according to the National Institute of Neurological Disorders and Stroke.
The study, which was presented at the annual meeting of the American Academy of Neurology, included 75 people who had "probable" diagnoses of dementia with Lewy bodies. Researchers conducted MRI brain scans on the study participants and also analyzed their sleep history to see if they had experienced REM sleep behavior disorder.
Researchers found the strong association between having the sleep disorder and having a definite dementia diagnosis. The association was particularly strong among men, and not as strong among women.
In addition to dementia, REM sleep behavior disorder has been associated with neurodegenerative diseases such as Parkinson's disease, WebMD pointed out. The sleep disorder is more common among elderly and middle-aged men.