Sleep disorders affect between 50 and 70 million Americans. But new research out of Aarhus University Hospital in Denmark shows that one particular sleep disorder may be caused by circulatory processes in the brain that also contribute to the development of Parkinson’s disease. This may help doctors anticipate Parkinson's and diagnose it at earlier stages.
Rapid Eye Movement Sleep Behavior Disorder (RBD for short) is an uncommon disorder characterized by restless sleep and flailing of the arms and legs during sleep. It’s caused by a disturbance in the rapid eye movement or REM sleep cycle.
Parkinson’s disease is a degenerative neurological disease that produces tremors, uncontrollable movements of the limbs, and other gross and fine motor issues. Eventually, the symptoms can become so severe as to prevent sufferers from being able to carry out daily functions.
The same processes behind disrupted sleep appear to also lead to a lack of oxygen in the brain tissue and the symptoms seen in Parkinson's disease.
To determine whether RBD could be considered an early-stage symptom of Parkinson’s, researchers followed 25 patients with rapid eye movement sleep behavior disorder and 25 healthy control patients. Each patient underwent sleep monitoring in a laboratory, and their brain, eye, muscle and heart activity were all tracked overnight.
Researchers found that RBD patients had low and at times obstructed blood flow in their brains compared to healthy test subjects. The cerebral cortex, the area of the brain most affected in the RBD subjects, is responsible for language processing, visual recognition and general cognition. All of these faculties are impacted over time by poor sleep quality and low blood circulation in the brain.
“We can see complications in the small blood vessels of the brain in patients with RBD,” Eskildsen said, “although these patients don't otherwise have any symptoms and the brain doesn't show other signs of disease.” The research team is hopeful that this information will help physicians identify early stage Parkinson’s disease in patients with sleep disorders that are a possible risk factor for the development of the disease.
More research will be needed to further investigate the relationship between blood flow in the brain and the later development of Parkinson’s symptoms.
The study is published in the journal, Brain.