Interdisciplinary Consensus in Evaluating the Severity Subscale of the Original and Revised Toronto Western Spasmodic Torticollis Rating Scale Through Video-Based Assessment: An Inter-Rater Reliability Study

Background: Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) is widely employed for cervical dystonia (CD) evaluation.

Objective: To assess the inter-rater reliability of the severity subscale of the original and revised TWSTRS using video recordings.

Methods: Three raters, a PhD student with a nursing degree, a physiotherapist specialized in CD, and a neurologist-in-training independently rated all videos. The inter-rater reliability was assessed with the intra-class correlation coefficient (ICC).

Results: The total severity score of both tools demonstrated a good inter-rater reliability (ICC = 0.87 to 0.88). The inter-rater reliability of individual sub-items varied from poor (ICC = 0.29) to excellent (ICC = 0.9).

Conclusions: The total severity score of both TWSTRS showed good inter-rater reliability in a multidisciplinary team, indicating their applicability for online patients' assessment. We recommend using the total subscale for outcome comparison. Furthermore, there is a need for more accurate definitions of duration factor and shoulder elevation.