Development and Preliminary Validation of a Parkinsonism-Dystonia Scale for Infants and Young Children

Abstract

Background: Parkinsonism in infancy is rare and is highly correlated with the presence of dystonia. Advances in treating and characterizing developmental and infantile degenerative parkinsonism have highlighted the need for a specialized assessment scale. Objective: The aim of this study was to design and validate a scale that effectively assesses parkinsonism-dystonia in early life. Methods: The Infantile Parkinsonism-Dystonia Rating Scale (IPDRS) was designed to capture the key clinical features of parkinsonism-dystonia in early life. It consists of 28 items across three subscales: Non-motor symptoms, Motor symptoms, and Dyskinesias. Thirty-two patients with hypokinetic movement disorder were scored following a standardized protocol. Filmed motor examinations were analyzed independently by three pediatric movement disorders specialists to evaluate interrater reliability. Twenty additional patients with primary neurotransmitter disorders were scored, and nine of them were evaluated at baseline and after treatment. Psychometric validation was conducted. Results: A total of 52 patients were scored using the IPDRS. Mean age was 3.1 years (standard deviation [SD]: 2.0), and the mean IPDRS score was 40.8 (SD: 13.17). Internal consistency analysis demonstrated a Cronbach's α of 0.21 for Non-motor symptoms subscale, 0.84 for Motor symptoms subscale, and 0.95 for Dyskinesia subscale. Kappa indexes exceeded 0.70 in seven items. Correlation coefficients for dystonia items with the Barry-Albright-Dystonia Scale ranged from 0.46 to 0.64. After treatment, all IPDRS scores changed significantly, with an effect size of 2.42. Conclusions: The IPDRS appears to be a reliable and valid tool for assessing parkinsonism in early life. Further validation studies with a larger sample size are needed to confirm these findings and complete the validation process. © 2025 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.