Movement Disorders Rating Scale for Children Aged 0-3 years: A Revision Study Design

Background: Movement Disorders - Childhood Rating Scale (MD-CRS 0-3) is a tool aimed to evaluate movement disorders in the first 3 years of life; however, with the experience gained in 10 years clinical practice, it has been possible, and necessary, to improve the characterization of the scale defining age-appropriate tasks according to age time windows and moving the MD severity from a three-point to a five-point scoring system. By using the scale in our clinical practice and in research, we realized that it was necessary to have more quantitative specifications, allowing a more precise scoring and a better definition of the psychometric properties. This study is a measurement-focused study of recorded video sessions and of video sessions which were carried out in in- and out-patient settings of IRCCS Fondazione Stella Maris aiming to revise the MD-CRS 0-3 and created the MD-CRS 0-3 R to promote and increase its use by improving its structure and items. Methods: A clinical sample of 90 eligible individuals—30 females and 60 males, mean age 2 years and 6 months, and age range 3 months – 3 years and 11 months—was included. Five raters independently and blindly scored the videotapes according to the MD-CRS 0-3 and the MD-CRS 0-3 R, with an interval of at least 6 months. Results: Inter-rater and Intraclass Correlation Coefficient values in all indexes of MD-CRS 0-3 R all exceeded 0.85. Standard Errors of the Measurement and Minimally Detectable Differences were very low. Overall, the MD-CRS 0-3 R exhibited improved psychometric properties compared to the original scale. Conclusions: The present study supports the use of the revised MD-CRS 0-3 in children under 4 years as a trustworthy, sensitive tool as for longitudinal assessments of movement disorder severity.