LAUSR

Sleep-related rhythmic movement disorder (SRRMD) is characterized by repetitive rhythmic motor behaviors involving large muscle groups that occur predominantly during stage N1 sleep. SSRMs are common in infants and children but they usually spontaneously resolve before adolescence. This case presents a rare adult case of SRRMD. A 60-year-old man initially presents to clinic for evaluation of repetitive movements needed to initiate sleep. Patient reports the problem starting in his childhood, where he needs to rock and roll intentionally in bed to fall asleep. He had been prescribed clonazepam 2mg and had been taking this along with doxylamine and melatonin nightly, but still reports frequent nocturnal awakenings due to body rolling. He specifically denies any hypnic kicking/jerking, or discomfort in legs while falling asleep. Patient has no excessive alcohol consumption, marijuana, or illicit drug use. Differentials for the patient’s condition include hyperarousal, chronic anxiety, iron deficiency, sleep-related breathing disorder, and rhythmic movement disorder. Patient consequently underwent an in-lab diagnostic polysomnography study which showed no evidence of sleep-related breathing disorders with AHI of 1.6 (AASM 3%). Sleep efficiency was low at 60.8% and sleep architecture showed decreased REM sleep and decreased N3 sleep. Rhythmic movements were noted during sleep and it was manifested by excessive transient muscle activity in both limb & chin EMG leads and also whole body rocking in the video recording. Moderate periodic limb movements were noted with PLM index to 17. Patient was seen in clinic 6 months later with persistent symptoms and his dose of clonazepam was increased slowly to 2.5 mg and then 3 mg. On the 3 mg of clonazepam, patient had resolution of symptoms. Our case describes a patient who had SRRMs that commenced in childhood persisting well into adulthood. Reported adult cases of SRRMD are few, and have been associated with sleep apnea, REM sleep behavior disorder, and RLS, while many remain idiopathic such as the case with this patient. While benzodiazepines are still first line for SRRMD, further work up and investigation into possible comorbid conditions could yield insight into the etiology and offer alternative treatment options to patients.