Rapid eye movement (REM) sleep is a very special part of sleep. It is your dream sleep. Most of the dreams that you remember after awakening have taken place during REM sleep. Most nightmares also happen in REM sleep. However, some dreams and nightmares do occur in other parts of sleep.

Dreams are often exciting and full of action. If our muscles are working correctly, our mind will tell them to run, hit, jump and talk. Doing this when you are awake is just fine. But when you are in bed asleep, it is not a good idea. In order to keep from acting out our dreams the muscles of our body are paralyzed during REM sleep. Our mind says move but the muscles don’t. A few muscles are left to work normally – eye muscles and breathing muscles.

  What would happen if the brain did not turn off the muscles during REM sleep?   
A person would move about, talk, hit, jump out of bed and generally do what he or she was dreaming. There is a good chance the person would get hurt, or maybe hurt someone else in the bedroom. This is different from sleep walking which happens when we are in deep sleep (not during REM sleep). We do not remember dreaming or walking during deep sleep, and almost never get hurt.

REM behavior disorder is the name we give for people who act out their dreams in their sleep. For example, one may fall out of bed, move about the bedroom, or run into objects during sleep. A person may kick the other person who is sleeping in the bed, bump his or her head against a nightstand, walk into a door or walk through a sliding glass window. Cuts, bruises, and broken bones to the sleeper or bed partner can occur.

REM behavior disorder happens more often in older people, and more often in men than in women. However, even young adults and children can have this happen. When some one is over tired, in a strange place, or stressed, anyone can have a night of REM behavior disorder. It can happen in perfectly normal people once or twice in a lifetime.

When it happens more often, the person may have (or may develop in the future) certain neurologic disorders such as Parkinson Disease. Other problems that may mimic REM behavior disorder include sleep walking and nocturnal epilepsy (seizures that occur during sleep).

People who have had more than one episode of REM behavior disorder should discuss this with their doctor. A referral to a Neurologist or Sleep Medicine specialist may be valuable. The standard of treatment is with a medication called clonazepam. This works in 9 out of 10 people. The medicine is taken before bedtime and will reduce or stop the dream behaviors. It is also important to keep the bedroom safe. Patients should keep all sharp or dangerous objects out of the way, protect windows and place sound alarms (tie a bell on the doorknob) to wake up the person.