The REM Sleep Behavior Disorder Screening Questionnaire: Validation Study of the Korean Version (RBDQ-KR)

REM sleep behavior disorder (RBD) is a parasomnia that is commonly associated with neurodegenerative disorders. We aimed to validate the Hong Kong version of the self-reported RBD questionnaire (RBDQ-HK) with the Korean version (RBDQ-KR) and to investigate its clinical usefulness.

One-hundred five patients with RBD and 105 age- and sex-matched controls were enrolled. Thirty were randomly selected for a retest with the questionnaire after 2 to 4 weeks without any treatment. Receiver operating characteristic curve and exploratory factor analysis were used to evaluate the scale, which had a score ranging from 0 to 100.

There was no difference in mean age and sex in patients with RBD and control subjects. Patients with RBD had a significantly higher total RBDQ-KR score than the control group (P < .001). The RBDQ-KR demonstrated high sensitivity (93.3%), specificity (89.5%), positive predictive value (89.9%), and negative predictive value (93.1%). Cronbach α coefficient for internal consistency of the total score of the RBDQ-KR was 0.9, which shows high reliability. Exploratory factor analysis showed two components, dream-related and behavioral factors, consistent with the main clinical features of RBD. Based on the results, the best cutoff for the total score ranging from 0 to 100 was at 18/19 and for factor 2 ranging from 0 to 75 was at 11.

This study showed RBDQ-KR is a valid and reliable questionnaire for RBD symptoms and severity in Korea. It serves as an effective tool to identify patients with RBD and to facilitate future clinical and research studies.