Background: The Modified Rush Video-Based Tic Rating Scale (MRVS) is the most widely used video-based scale for assessing tic severity in patients with Tourette syndrome (TS). However, shortcomings of the MRVS, including a lack of clear instructions, a time-consuming recording procedure, and weak correlations with the gold standard for tic assessment, the Yale Global Tic Severity Scale-Total Tic Score (YGTSS-TTS), limits its use in research settings, although video assessments are generally considered objective, reliable, and time-saving measurements.
Objectives: We aimed to revise the MRVS (MRVS-R) to simplify and standardize the assessment procedure and improve the correlation with the YGTSS-TTS.
Methods: We used 102 videos of patients with TS or persistent motor tic disorder filmed according to the MRVS. We compared the tic frequency assessed by MRVS with frequencies according to MRVS-R based on a 5-min (instead of a 10-min) video to investigate whether reducing the recording time leads to significant changes. In addition, we adapted the MRVS to the YGTSS and defined new anchor values for motor and phonic tic frequency based on frequency distributions as assessed in our sample. Finally, we compared the MRVS-R and MRVS regarding psychometric properties and correlation with the YGTSS-TTS.
Results: Cutting video recording time in half did not significantly affect assessments of motor and phonic tic frequencies. Psychometric properties were acceptable. Most important, proposed revisions of the MRVS improved correlation with the YGTSS-TTS.
Conclusions: The MRVS-R is a simplified version of the MRVS with comparable psychometric qualities, but higher correlations with the YGTSS-TTS.
Keywords: Tourette syndrome; assessment; tic disorders; tics; video rating.
© 2023 International Parkinson and Movement Disorder Society.