Objective: To assess the inter-rater reliability of the severity subscale of the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) in a multidisciplinary team.

Background: The TWSTRS is widely employed. As patients are treated by a multidisciplinary team, it is essential to know whether different care givers come to the same conclusion.

Method: Adult patients with isolated cervical dystonia were videotaped according to the standardized protocol of the TWSTRS [1]. The severity subscale has six sub-items to rate the severity of the symptoms.  The maximum score of the items is 35 with the duration factor weighted twice. Three raters, a PhD student with a nursing degree, a physiotherapist and a neurologist-in-training independently rated all videos. The overall level of inter-rater reliability agreement was assessed with the intra-class correlation coefficient (ICC). Statistical Package for Social Sciences (SPSS) version 24.0 was used for analysis.

Results: Twenty five unique patients with cervical dystonia (88% women) were videotaped. Eighteen subjects were recorded on multiple occasions, yielding a total of eighty nine videos. The mean total score of the TWSTRS was 15.65 + 4.78 points, 15.69 + 3.78 points, and 18.15 + 4.10 points, as rated by the first, second, and the third rater, respectively. The total severity sub-score demonstrated good inter-rater agreement (ICC = 0.82). Individual items such as rotation, anterocolis, laterocolis, retrocolis, shoulder elevation, range of motion, and time at midline demonstrated moderate to good performance (ICC = 0.56 to 0.86). However, the inter-rater agreement of lateral shift, sagittal shift, duration factor, and effect of sensory trick were found to be poor (ICC = 0.19 to 0.41).

Conclusion: Inter-rater reliability of the separate items of the severity subscale is poor in contrast to the good inter-rater agreement of the total severity subscale score. We advise to only compare total scores and not focus on sub-items.

References: 1. Comella, C.L., et al., Teaching tape for the motor section of the Toronto Western Spasmodic Torticollis Scale. Movement disorders: official journal of the Movement Disorder Society, 1997. 12(4): p. 570-575.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/reliability-of-the-severity-subscale-of-the-toronto-western-spasmodic-torticollis-rating-scale-in-a-multidisciplinary-team/