The REM Sleep Behavior Disorder Screening Questionnaire is not Valid in De Novo Parkinson's Disease

Background: Rapid eye movement (REM) sleep behavior disorder (RBD) is one of the most specific prodromal indicators for Parkinson's disease (PD). Objectives: To test the validity of the RBD-Screening Questionnaire (RBDSQ) in assessing RBD in early PD. Methods: The RBDSQ was completed before video-supported polysomnography (vPSG) by 134 de novo PD patients, 109 matched controls without neurological disorder (CTR) and 30 subjects with idiopathic RBD (iRBD) without clinical signs of PD; results were compared with vPSG-confirmed RBD diagnosis. Results and Conclusions: Sensitivity/specificity of the RBDSQ for the PD cohort were 0.44/0.84 at the previously published cut-off score of 6 for PD patients, and the area under the curve (AUC) 0.68 (95% CI, 0.56–0.79). By contrast, in the iRBD/CTR cohort the RBDSQ (cut-off = 5) had a sensitivity/specificity of 0.97/0.84 and an AUC of 0.95 (95% CI, 0.90–1.00). Subanalysis of question 6 only (4 subitems asking for dream enactment) at a cut-off score of 1 revealed a sensitivity of 0.74 and a specificity of 0.70 for the de novo PD cohort, AUC was 0.74 (95% CI, 0.63–0.84). RBDSQ is an insufficient screening tool for RBD in de novo PD. New screening tools for RBD assessment need to be developed.