Twitching, tossing, kicking and even punching while dreaming is often an early sign of degenerative nerve disorders, researchers concluded.

Physically acting out dreams, also known as rapid eye movement behavior disorder (RBD), develops into degenerative nerve disorders in 40 to 65 percent of patients, such as Parkinson's disease, researchers found.

Ronald Postuma, a sleep expert at the University of Montreal, and co-authors reviewed over 10 years of sleep studies and published their findings Oct. 14 in the journal Neurobiology of Disease.

Patients who have Parkinson's disease slowly lose control of their motor functions and eventually die. The disease appears on average four to 12 years after the onset of RBD symptoms, Postuma wrote.

The sleep disorder also poses short-term risks, such as when a patient dreams about being in a fight wakes up after hitting their bed partner.

The link between RBD and nerve disorders later in life is important for sleep specialists to know about, said William Kohler, medical director of the Florida Sleep Institute in Spring Hill, Fla. and assistant director of Florida Hospital in Tampa. Kohler, who was not involved in the study, has studied sleep disorders for over 40 years.

I think it's a very important article, Kohler said. Doctors need to be more cognizant of the neurodegenerative process.

Patients don't go to the sleep doctor expecting to find out they may have a deadly neurodegenerative disease, Kohler said. He explained that doctors should know about the link between RBD and nerve disorders, but they should also take care to rule out other RBD triggers.

Certain antidepressants as wells as withdrawal from alcohol or sedative-hypnotic medications can lead to RBD, according to WebMD.

Symptoms of RBD are not a cause for panic, Kohler said.

One has to always be careful not to frighten people, he said. It's not a definitive finding.