Diagnosis of REM sleep behavior disorder Ji Eun Kim, M.D., PhD. Department Neurology, School of Medicine, Catholic University of Daegu, Institute of Brain and Neural Science, Catholic University of Daegu REM sleep behavior disorder (RBD) is characterized by abnormal behaviors emerging during REM sleep that cause injury or sleep disturbance. RBD is also associated with electromyographic abnormalities during REM sleep. The EMG demonstrates an excess of muscle tone or phasic EMG twitching activity during REM sleep. Sleep related injurious, potentially injurious, or disruptive behaviors by history and characteristic polysomnographic findings are essential for diagnosis of RBD. In this article, previous and current diagnostic criteria of RBD will be reviewed.