Validation of a new REM sleep behavior disorder questionnaire (RBDQ-HK)

Sleep Med. 2010 Jan;11(1):43-8. doi: 10.1016/j.sleep.2009.06.008. Epub 2009 Nov 30.


Objectives: There are limited screening instruments for diagnosis of REM sleep behavior disorder (RBD) and none for quantifying the severity of disease. We aimed to validate a 13-item self-reported RBD questionnaire (RBDQ-HK) for diagnostic and monitoring purposes.

Methods: Based on ICSD-II and our previous clinical and empirical work, the RBDQ-HK questionnaire was designed and administered in patients attending university-affiliated sleep clinic and psychiatric out-patient clinic, and subjects from the general population. ROC curve and exploratory factor analysis were employed to evaluate the scale, which had a score ranging from 0 to 100.

Results: One hundred and seven RBD patients [mean age 62.6 (15.5) years; male 70.1%] and 107 control subjects [mean age 55.3 (9.0) years, male 57.9%] completed the questionnaire. The diagnoses of all the study subjects were independently ascertained by clinical interview and PSG. RBD patients had a significantly higher total RBDQ-HK score [mean (s.d.): 32.1 (16.1), range 3-71] than the control group [9.5 (10.2), range 0-55] (p<0.005). The RBDQ-HK demonstrated robust psychometric properties with moderate sensitivity (82.2%), specificity (86.9%), positive predictive value (PPV; 86.3%), and negative predictive value (NPV; 83.0%), high internal consistency and test-retest reliability. Exploratory factor analysis revealed two components (dream-related and behavioral factors) that corresponded to the essential clinical features of RBD. The best cut-off for total score (range 0-100) was at 18/19 and the best cut-off for factor 2 (behavioral factors including sleep talking, shouting, limb movements and sleep-related injuries, range 0-70) was at 7/8.

Conclusions: The RBDQ-HK has satisfactory validity and reliability as a measure of clinical RBD symptoms and severity. It may serve as an effective tool for diagnosis and evaluation of the disease course to facilitate future clinical and research studies.

MeSH terms

  • Adult
  • Aged
  • Factor Analysis, Statistical
  • Female
  • Hong Kong
  • Humans
  • Male
  • Mass Screening
  • Middle Aged
  • Polysomnography
  • Psychometrics / statistics & numerical data
  • REM Sleep Behavior Disorder / classification
  • REM Sleep Behavior Disorder / diagnosis*
  • REM Sleep Behavior Disorder / etiology
  • ROC Curve
  • Reproducibility of Results
  • Surveys and Questionnaires*