Responsiveness of the Movement Disorder-Childhood Rating Scale in children with movement disorders undergoing oral therapy with tetrabenazine

Introduction Tetrabenazine (TBZ) is widely used to treat adults with movement disorders and it is also used in paediatric practice off‐label, but there are conflicting reports regarding its efficacy on movement disorders. We aim to explore the effectiveness of TBZ in a sample of children with movement disorders (caused by different aetiologies) evaluated using the Movement Disorder‐Childhood Rating Scale (MD‐CRS), before starting TBZ (T0), after 6 months, (T1) and after 12 months (T2) of therapy. Patients and methods Twenty‐one children (mean age 9y±3.94y): 16 participants with dystonia and 5 with chorea as the prevalent movement disorder. All assessments were recorded on video and the videotapes collected in all participants were independently and blindly rated in respect to timing of recording (T0, T1, and T2) by a clinician with experience in the field of movement disorders. Univariate repeated measures using analysis of variance (ANOVA) with Greenhousee Geisser correction was performed to analyse scale responsiveness for the three indexes (e.g. Index 1, Index 2, and Global Index) in each group with time (T0, T1, and T2). In addition, the Bonferroni test was performed to identify the source of significant differences among means. Results ANOVA indicated a main effect of time for each index; Index 1: F(1.760, 32.721)=9.158, p<0.001; Index 2: F(1.727, 35.541)=14.160, p<0.001; Global Index: F(1.636, 32.721)=17.616, p<0.001). The Bonferroni post hoc test revealed that change scores were statistically significant between all time points for all indexes. Conclusion Our results confirm, as already reported, that MD‐CRS is a suitable tool to detect changes and could be used as an outcome measure for clinical trials.