» Articles » PMID: 39327269

Validation of the International REM Sleep Behavior Disorder Study Group Symptoms Severity Scale (IRBD-SSS): a New Tool to Assess RBD Clinical Severity

Abstract

Background: Currently, no standard scale has been validated to assess overall severity of RBD symptoms in the home environment. We aimed to evaluate the psychometric properties of the International RBD Severity Scale (IRBD-SSS), a new tool designed by the International RBD Study Group.

Methods: Two versions of the IRBD-SSS were created, one for the patient (IRBD-SSS-PT) and another for the bedpartner (IRBD-SSS-BP), both consisting of 3 components, namely vocalizations, body movements and injury, with a fourth component (patient version only) evaluating dream content. To score each dimension, the frequency and severity/impact of behaviors during the previous month are multiplied. Psychometric properties of the IRBD-SSS were assessed, including reproducibility.

Results: A total of 188 subjects including n = 132 RBD patients (n = 94 isolated RBD and n = 38 symptomatic RBD) and n = 52 bedpartners were enrolled from eight Sleep centers across France and Italy. Participants completed the scale at baseline and after one week. Acceptability of the scale was excellent in patients (97%) and bedpartners (98%). Internal consistency was acceptable for IRBD-SSS-PT (Cronbach α = 0.75) while slightly low for IRBD-SSS-BP (Cronbach α = 0.49). Concurrent validity was good for both patient (r = 0.70;p < 0.001, see Figure) and bedpartner (r = 0.69;p < 0.001) IRBD-SSS. Reproducibility was high for IRBD-SSS-PT (Lin's coefficient of agreement = 0.85 [0.81;0.90]) and good for the IRBD-SSS-BP (0.79 [0.68;0.90] (p < 0.001).

Conclusions: Both the patient and bedpartner versions of the IRBD-SSS showed excellent acceptability, acceptable internal consistency, good external validity and high reproducibility. IRBD-SSS is a useful tool to test the severity of RBD symptoms in clinical settings and clinical trials.

Trial Registration: NCT04071899.

References
1.
Schenck C, Bundlie S, Ettinger M, Mahowald M . Chronic behavioral disorders of human REM sleep: a new category of parasomnia. Sleep. 1986; 9(2):293-308. DOI: 10.1093/sleep/9.2.293. View

2.
Schenck C, Mahowald M . REM sleep behavior disorder: clinical, developmental, and neuroscience perspectives 16 years after its formal identification in SLEEP. Sleep. 2002; 25(2):120-38. DOI: 10.1093/sleep/25.2.120. View

3.
Postuma R, Gagnon J, Montplaisir J . Clinical prediction of Parkinson's disease: planning for the age of neuroprotection. J Neurol Neurosurg Psychiatry. 2010; 81(9):1008-13. DOI: 10.1136/jnnp.2009.174748. View

4.
Stiasny-Kolster K, Mayer G, Schafer S, Moller J, Heinzel-Gutenbrunner M, Oertel W . The REM sleep behavior disorder screening questionnaire--a new diagnostic instrument. Mov Disord. 2007; 22(16):2386-93. DOI: 10.1002/mds.21740. View

5.
Li S, Wing Y, Lam S, Zhang J, Yu M, Ho C . Validation of a new REM sleep behavior disorder questionnaire (RBDQ-HK). Sleep Med. 2009; 11(1):43-8. DOI: 10.1016/j.sleep.2009.06.008. View