Innsbruck REM Sleep Behavior Disorder Inventory may distinguish abnormal nocturnal movements related to obstructive sleep apnea

Background Rapid eye movement (REM) sleep behavior disorder (RBD) is characterized by recurrent dream enactment behaviors like sleep-related vocalization and/or complex motor behaviors. Objective To investigate the discriminative role of the validated Turkish version of the 9-Item Innsbruck REM Sleep Behavior Disorder Inventory (IRBD-9-Turkish) for idiopathic RBD (iRBD) in patients with obstructive sleep apnea (OSA). Methods The current multicenter study was prospectively conducted in 13 accredited sleep centers in 10 different cities in Türkiye. Clinical data was obtained through a preformed questionnaire, and all participants were submitted to a full-night video-polysomnography (video-PSG) session in a sleep laboratory. Results A total of 105 patients (mean age: 58.3 ± 11.6 years; 68.6% of male subjects) were prospectively and consecutively enrolled in the study; 51 patients (48.6%) presented iRBD, and 54 (51.4%), OSA, 19 (35.2%) of whom presented abnormal nocturnal behaviors (NBs) demonstrated by clinical and video-PSG findings associated with arousal reactions secondary to apneas and hypopneas. The cut-off value of the IRBD-9 was higher in patients with OSA-NBs than in those with OSA without NBs (p < 0.001), with a sensitivity of 0.765 and a specificity of 0.667, resulting in a correct diagnosis of NBs in 75% of patients with OSA. The receiver operating characteristic (ROC) curves for Factor I (items 1, 2, 3, 6, and 8) and Factor II (items 4, 5, 7, and 9) of the IRBD-9-Turkish showed that both factors were able to distinguish patients with iRBD from those with OSA, but only Factor I distinguishes patients with iRBD from those with OSA-NBs. Conclusion The present study demonstrated a very high sensitivity and specificity of the IRBD-9-Turkish not only in patients with iRBD, but also in patients with OSA. 2025. The Author(s).