Rapid Eye Movement (REM) sleep behavior disorder: a sleep disturbance affecting mainly older men

Rapid Eye Movement (REM) sleep behavior disorder is characterized by the intermittent loss of REM-related muscle atonia and the appearance of elaborated motor behaviors (sometimes violent behavior) and vocalizations associated with dream mentation. Nine patients were diagnosed in our Sleep Disorders Unit with this syndrome during the period August 1997-April 2000. All were male, average age 67.9 +/- 6.9 years. The complaint of all our patients was the occurrence of violent or injurious sleep behavior mainly during the dream stage. Jumping or falling out of bed and slapping or beating their wives were more common. None had history or showed signs of dementia, Parkinson or other neurodegenerative diseases. A relative high amount of SWS (20.9%) was found. Seven showed an intermittent increase in chin EMG tonus while the other two had an almost continuous high chin EMG tonus during REM sleep. We did not observe any violent motor behavior during the polysomnographic recordings. Phasic activities during REM sleep were high but density quantification was not performed. Six patients had also Periodic Limb Movement (PLM) Disorders, four had also Obstructive Sleep Apnea (OSA) Syndrome. The treatment recommended to all patients was Clonazepam beginning with a 0.5-mg dose. Four patients reported a decrease or disappearance of sleep agitation and nightmares and were very happy with the treatment and without side effects. The others decided not to try Clonazepam or stopped after a few days of using it. RBD appears to be a sleep disturbance affecting mainly aged men. Its violent expression may frighten the patients and their bed-partners and may cause injury to both. In some cases this sleep disorder seems to be an early manifestation of a neurodegenerative disorder while in others it may represent only an idiopathic form. Clonazepam at lower doses is a good agent for the treatment of this condition.