Acting out dreams linked to development of dementia, study finds

March 21, 2013

The strongest predictor of whether a man is developing dementia with Lewy bodies—the second most common form of dementia in the elderly—is whether he acts out his dreams while sleeping, Mayo Clinic researchers have discovered. Patients are five times more likely to have dementia with Lewy bodies if they experience a condition known as rapid eye movement (REM) sleep behavior disorder than if they have one of the risk factors now used to make a diagnosis, such as fluctuating cognition or hallucinations, the study found.

The findings were being presented at the annual meeting of the American Academy of Neurology in San Diego. REM sleep behavior disorder is caused by loss of the normal that occurs during REM sleep. It can appear three decades or more before a diagnosis of dementia with Lewy bodies is made in males, the researchers say. The link between dementia with Lewy bodies and the sleep disorder is not as strong in women, they add.

"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," says lead investigator Melissa Murray, Ph.D., a neuroscientist at Mayo Clinic in Florida.

The study's findings could improve diagnosis of this dementia, which can lead to beneficial treatment, Dr. Murray says.

"Screening for the sleep disorder in a patient with dementia could help clinicians diagnose either dementia with Lewy bodies or Alzheimer's disease," she says. "It can sometimes be very difficult to tell the difference between these two dementias, especially in the early stages, but we have found that only 2 to 3 percent of patients with Alzheimer's disease have a history of this sleep disorder."

Once the diagnosis of dementia with Lewy bodies is made, patients can use drugs that can treat issues, Dr. Murray says. No cure is currently available.

Researchers at Mayo Clinic in Minnesota and Florida, led by Dr. Murray, examined magnetic resonance imaging, or MRI, scans of the brains of 75 patients diagnosed with probable dementia with Lewy bodies. A low-to-high likelihood of dementia was made upon an autopsy examination of the brain.

The researchers checked the patients' histories to see if the sleep disorder had been diagnosed while under Mayo care. Using this data and the brain scans, they matched a definitive diagnosis of the sleep disorder with a definite diagnosis of dementia with Lewy bodies five times more often than they could match , such as loss of brain volume, now used to aid in the diagnosis. The researchers also showed that low-probability dementia with Lewy bodies patients who did not have the sleep disorder had findings characteristic of Alzheimer's disease.

"When there is greater certainty in the diagnosis, we can treat patients accordingly. with Lewy bodies patients who lack Alzheimer's-like atrophy on an MRI scan are more likely to respond to therapy—certain classes of drugs—than those who have some Alzheimer's pathology," Dr. Murray says.

Explore further: Violent sleep disorder linked to a form of dementia

Related Stories

Violent sleep disorder linked to a form of dementia

May 17, 2007

Mayo Clinic researchers and a group of international collaborators have discovered a correlation between an extreme form of sleep disorder and eventual onset of parkinsonism or dementia. The findings appear in the current ...

Personality changes may help detect form of dementia

May 28, 2007

ST. PAUL, MN – A simple personality test could help doctors detect dementia with Lewy bodies, a form of dementia often confused with Alzheimer's disease, sooner, according to a study published in the May 29, 2007, issue ...

Recommended for you

Special nerve cells cause goose bumps and nipple erection

August 29, 2016

The sympathetic nerve system has long been thought to respond the same regardless of the physical or emotional stimulus triggering it. However, in a new study from Karolinska Institutet published in the Nature Neuroscience, ...

A new window to understanding the brain

August 29, 2016

Scientists in recent years have made great strides in the quest to understand the brain by using implanted probes to explore how specific neural circuits work.

Next steps in understanding brain function

August 26, 2016

The most complex piece of matter in the known universe is the brain. Neuroscientists have recently taken on the challenge to understand brain function from its intricate anatomy and structure. There is no sure way to go about ...

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.