Rapid Eye Movement (REM)-Predominant Central Sleep Apnea With Alpha-Delta Sleep Pattern: A Case Report

Central sleep apnea (CSA) occurring predominantly during rapid eye movement (REM) sleep represents an unusual clinical phenomenon, as CSA typically occurs during non-rapid eye movement (NREM) sleep. We present the case of a 32-year-old male with severe obstructive sleep apnea (OSA), with an apnea-hypopnea index (AHI) of 65.5/hr, who exhibited central apneas mainly during REM sleep (central apnea index: 35.9/hr in REM vs. 5.2/hr in NREM), along with concurrent alpha-delta sleep pattern during slow-wave sleep. The patient was taking tramadol 100 mg and pregabalin 300 mg daily for chronic back pain. Continuous positive airway pressure (CPAP) therapy at 6 cmH₂O effectively managed the OSA and resolved both central apneas and the alpha-delta sleep pattern despite continued medication use. The CPAP therapy reduced the total AHI from 65.5/hr to 1.3/hr, with the central apnea index decreasing from 35.9/hr to 0/hr during REM sleep. This case contributes to the limited literature on REM-predominant CSA and demonstrates the efficacy of standard CPAP therapy in this uncommon presentation, suggesting complex interactions among pharmacological agents, sleep architecture, and respiratory control mechanisms.