Category: Rating Scales
Objective: The objective of this study is to assess the internal validity of the REM Sleep Behavior Disorder (RBD) symptom severity scale (RBDSSS) and its correlation to the clinical global impression of severity (CGI-S) in a cohort of participants enrolled in the North American Prodromal Synucleinopathy (NAPS) study.
Background: RBD is a prodromal marker of α-synucleinopathies with no standardized tool for assessing severity in clinical or research practice. Development of a reliable scale is essential to understand risk of phenoconversion, monitor response to treatment and clinical trial design.
Method: Participants and their bedpartners enrolled in the NAPS cohort filled out a self-reported questionnaire of RBD-SSS developed by the International RBD study group. The CGI-S is a 7-point scale ranging from normal (1) to most severely ill (7) and was completed by a clinician based on an independent interview with the participant ± their bedpartners. Data was included if both participants (RBDSSS-PT) and bedpartner (RBDSSS-BP) responses to the RBDSSS questionnaire were available in addition to the CGI-C score. Responses to RBDSS questions were assigned point values based on frequency and severity of symptoms. Points were summed for individual RBDSSS-PT scores (total possible=31) and for RBDSSS-BP scores (total possible=23).
Results: This cohort (n=212) included in this analysis was predominantly male (n=175) with a mean ± SE age of 65.16 ± 1.46 years. The median (interquartile range) for RBDSSS-PT, RBDSSS-BP and CGI-S was 12 (7-16), 8.5 (6-11.3) and 3 (3-4), respectively. Non-parametric Spearman’s rank correlation coefficients (rs) for each variable pair are as follows: RBDSS-PT vs. RBDSS-BP, rs=0.613; RBDSS-PT vs. CGI-C, rs=0.640; RBDSS-BP vs. CGI-C, rs=0.446 (P<0.0001).
Conclusion: A moderate correlation was observed between RBDSSS-PT and RBDSSS-BP suggesting good internal validity for the scale. CGI-S correlated moderately with RBDSSS-PT and weakly with RBDSSS-BP.
To cite this abstract in AMA style:
A. Busicescu. Development and validation of clinical scales for defining RBD severity in participants of the North American Prodromal Synucleinopathy (NAPS) consortium [abstract]. Mov Disord. 2022; 37 (suppl 2). https://www.mdsabstracts.org/abstract/development-and-validation-of-clinical-scales-for-defining-rbd-severity-in-participants-of-the-north-american-prodromal-synucleinopathy-naps-consortium/. Accessed May 13, 2025.« Back to 2022 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/development-and-validation-of-clinical-scales-for-defining-rbd-severity-in-participants-of-the-north-american-prodromal-synucleinopathy-naps-consortium/