During the REM state of sleep there is activation of brain pathways, which generate vivid dreams, and also activation of brain pathways, which turn the muscles off. In some people the pathway to turn the muscles off fails and they act out their dreams. This is referred to as REM behavioral disorder (RBD). Dreams during the REM state are usually action-packed and sometime violent, therefore it not uncommon for patients with RBD to injure themselves or their bed partner during sleep without any memory of the events. RBD is a chronic progressive disorder with increasing complexity, intensity and frequency of dream enactment. Movement activity may range for irregular swinging of limbs while in bed to springing out of bed and performing organized series of movements, e.g., running into the wall or punching or blocking maneuvers. Verbal output may range for irregular groans or shouts to complex angry arguments.
Victims: Greater than 90% of RBD is seen in men over 65 years of age.
Cause: Most scientists in the field of sleep medicine agree that there is an abnormality in the pontine (brain stem) mechanism, which normally inactivates muscles during REM. Nerve cell degeneration has been considered given the late onset in life, hormonal influences have been considered given the male predominance and genetics have been considered given cases of familial aggregation.
Diagnosis: The diagnosis is usually established with a history of problem sleep behavior coupled with Polysomnography with video monitoring. The polysomnogram classically shows augmentation of muscle activity during REM instead of the usually inactivation. The video usually confirms excessive body and limb movements and occasional complex violent movements.
Treatment: Benzodiapines and antidepressants have been used most commonly for this disorder. The benzodiapine, clonazepam is particularly effective with apparent little abuse potential in this patient population.