During a large-scale study of the socioeconomic costs of Parkinson’s, Danish researchers from the University of Copenhagen discovered that very early symptoms of this neurodegenerative disease may be revealed in dream or REM sleep.

"In the study we saw that 8 years before diagnosis, Parkinson’s sufferers exhibited work and health indications that something was wrong," says Poul Jennum, professor of clinical neurophysiology at the Center for Healthy Ageing, University of Copenhagen, and the Sleep Centre at Glostrup Hospital.

Among the very early symptoms is the sleep disorder RBD, or REM behavior disorder.

"Our hypothesis is that the very earliest stages of Parkinson’s disease show up as various other diseases such as RBD," Jennum says.

In recent years, great advances have been made in the treatment of Parkinson’s disease, but there are still no therapies to mitigate the later symptoms, costs, and increased mortality of the disease.

"This may become possible if we are able to intervene earlier, and if we are able to find clear indications of Parkinson’s disease 8 years sooner than we are now, this may give us an important tool. The question is, of course, whether we can actually say that RBD is always a very early marker for Parkinson’s disease. That is what we are now investigating at the Sleep Centre at Glostrup Hospital," says Jennum.

For the study, researchers used the National Patient Register to identify all the patients diagnosed with Parkinson’s disease between 1997 and 2007. The 13,700 patients were compared to 53,600 healthy patients of the same sex, social class, educational background, etc. The study was carried out by researchers from the Center for Healthy Ageing, the Danish Center for Sleep Medicine, University of Copenhagen, Glostrup Hospital, Bispebjerg Hospital and the Danish Institute of Health Research, and was published in the Journal of Neurology.