Validation of the Beijing version of the REM sleep behavior disorder questionnaire (RBDQ-Beijing) in a mainland Chinese cohort.

REM sleep behavior disorder (RBD) is one type of parasomnia characterized by nocturnal complex motor activity associated with dream mentation. Growing evidence has indicated that RBD is a preclinical stage of neurodegenerative diseases. Therefore screening RBD patient is becoming important. The RBD Questionnaire-Hong Kong (RBDQ-HK) is an effective questionnaire to screen RBD patients. However, it is hard to distinguish RBD with the questionnaire from severe OSAS patients, who could mimic some symptoms of RBD patients. Therefore, we made RBDQ-Beijing by adding two screening questions for OSAS into original RBDQ-HK, including habitual loud snoring and witnessed apnea during sleep. To validate and compare these two questionnaires, 224 subjects were enrolled and screened with these questionnaires, and consequently analyzed with video-polysomnography. Receiver-operator characteristics curve analysis was conducted to attain the best cut-off values of the RBDQ-HK and RBDQ-Beijing. For the RBDQ-HK, the sensitivity was 97.1% and the specificity was 83.2%. More than half of misclassified RBD patients were proved to be severe OSAS patients. For the RBDQ-Beijing, the sensitivity was 95.8% and specificity was 94.3%, indicating that our questionnaire is able to distinguish RBD from severe OSAS patients. In conclusion, RBDQ-Beijing is of help to improve the specificity in RBD screening without excluding the patients with RBD combined OSAS. Therefore the RBDQ-Beijing may be a better screening and preliminary diagnostic tool for RBD than the RBDQ-HK. Moreover, the RBDQ-Beijing would be important for early diagnosis of neurodegenerative diseases and for prevention of injuries to the patient or the patient's bed partner.