Link Between Sleep Disorder and Dementia

Researchers at the Mayo Clinic have concluded that those male patients who suffer from a specific sleep disorder known as REM sleep behavior disorder are more likely to later develop a specific type of dementia called Lewy body dementia. The new information was recently presented at a meeting of the American Academy of Neurology that was held in San Diego, California.  This finding that problems with sleep may be indicative of cognitive disorders later is a first, and is particularly significant because Lewy body dementia is extremely common, and is second only to Alzheimer’s disease as a form of dementia in the United States. The sleep disorder that acts as a precursor to the condition is characterized by having dreams that are acted out during sleep. Lewy body dementia is so named because those who have the condition are found to have clumps of accumulated proteins, called Lewy bodies, stuck in the areas of the brain that are associated with movement and thinking. People who suffer from the condition are prone to having hallucinations, motor deficits and cognitive fluctuations. The condition can range in severity and falls somewhere between Alzheimer’s disease and Parkinson’s disease in terms of the degree of impairment that it causes. The illness is diagnosed based on behaviors but can not be confirmed without the benefit of an autopsy. The scientists from Mayo made their remarkable discovery following a study in which they pulled the medical histories from 75 patients who had been confirmed following brain autopsy to have had Lewy body dementia. By examining their records they determined that those male patients who were confirmed to have had LBD were five times more likely to have suffered from REM sleep behavior disorder than any other symptom or characteristic in their health profile. The same was not true of female LBD patients, for whom there was no such trend. The possibility that there was a link between dementia and this particular sleep disorder has been raised before; about ten years earlier professionals attending the Dementia with Lewy Bodies Consortium indicated that REM sleep behavior disorder might be considered a leading symptom or flag for the development of the disorder. The new findings are significant enough that, even without the inclusion of a control group in this study, professionals are calling for REM sleep behavior disorder to be added as one of LBD’s core features.  Though the reason behind the link is not yet clear, it may be a matter of Lewy bodies beginning to accumulate in areas of the brain associated with sleep years before the signs of the dementia begin to appear. In some cases these signs begin to show up as long as thirty years prior to the dementia. Dr. Melissa Murray, assistant professor at the Mayo Clinic in Florida, says that approximately half of all people who exhibit signs of REM sleep behavior disorder will eventually show signs of Lewy body dementia. Knowing this may be helpful when it comes to prescribing medications to address symptoms of dementia, or in developing plans for patient care long in advance.