Severe Central Sleep Apnea/Hypopnea Syndrome Mimicking Rapid Eye Movement Sleep Behavior Disorder

Abstract

Rapid eye movement sleep behavior disorder (RBD) is a sleep disorder characterized by loss of muscle atonia during rapid eye movement (REM) sleep associated with dream enactment.1 RBD may be idiopathic or associated with neurodegenerative diseases.1 Patients with RBD display complex motor behaviors such as gesturing, falling, talking, and shouting that are associated with unpleasant dreams. However, these abnormal sleep behaviors can also occur in other sleep disorders such as obstructive sleep apnea syndrome (OSAS).2 This clinical situation has been termed “pseudo-RBD”. Iranzo and Santamaria2 have identified patients who presented with abnormal sleep behaviors and unpleasant dreams in addition to OSAS. “Pseudo-RBD” has been reported in five cases of severe OSAS, they presented violent behaviors during OSAS-induced arousals from REM sleep.3 Other anecdotal reports of OSAS simulating the clinical features of RBD also have been reported.4,5 Nevertheless, there have been no previous reports of pseudo-RBD associated with central sleep apnea-hypopnea (CSAH) syndrome. Here, we describe two patients who display complex behaviors mimicking RBD, but REM sleep without atonia was not observed in videopolysomnography (VPSG). Furthermore, VPSG demonstrated abnormal motor behaviors related to arousals induced by severe CSAH.