0806 REM sleep without atonia in the Setting of Duchenne muscular dystrophy: Can it Serve a Protective Role?

Abstract

Introduction: Duchenne muscular dystrophy (DMD) has wellknown associations with sleep-related breathing disorders such as sleep apnea and nocturnal hypoventilation. These disorders naturally follow from the progressive muscle weakness that is the hallmark of DMD. New data is emerging on the prevalence of other polysomnographic features affecting patients with DMD, particularly as they relate to the phenotype of the sleep disorders unique to DMD. We report on a patient with REM sleep without atonia (RWA) in DMD. Report of Cases: A 13-year-old male with DMD was referred for a polysomnogram (PSG) due to new-onset snoring, but there was no history to suggest dream enactment behavior. He was not taking any CNS-acting medication such as serotonergic or sedativehypnotic medications. Neurologic examination was notable for diffuse symmetric muscle weakness requiring the use of a wheelchair. PSG revealed obstructive sleep apnea syndrome with an apnea-hypopnea index of 3/hr overall and 5/hr during REM sleep, a respiratory disturbance index of 9/hr with minimum O saturation of 84%, and evidence of RWA in three 30-second epochs meeting AASM scoring criteria. Dream-enactment behavior was absent during the PSG and historically. Conclusion: We report on a previously unrecognized finding of RWA the setting of DMD. While sleep studies are routinely performed in DMD due to the significant association with sleep-disordered breathing and REM-related hypoventilation, the presence of RWA was unusual. The finding of RWA in the setting of a dystrophinopathy prompts important questions. While it is unlikely that RWA is an emerging sign of an synucleinopathy in the setting of DMD, its presence in a young teenager raises the possibility of hypocretin deficiency in the setting of DMD, as is the case with myotonic dystrophy type 1 reflecting impaired hypocretin neurotransmission. However, a more attractive explanation is that RWA may promote a protective effect against sleep apnea in patients with vulnerability to REMrelated hypoventilation. Our data suggest a potential protective role conferred by the preservation of muscle tone in the setting of sleep apnea in neuromuscular conditions.