The Relationship Between Limb Dystonia Severity and Functional Impact in Children With Cerebral Palsy.

Dystonia treatment evaluation in cerebral palsy (CP) is limited by the lack of clinician-assessed scales linking dystonia severity to functional impact. We asked 7 pediatric movement disorder specialists to review videos of 27 children with CP while performing an upper extremity task and while walking. Experts rated arm and leg dystonia severity using the Global Dystonia Severity Rating Scale (GDRS) and task-specific functional impact on a 5-point scale adapted from the Dyskinetic Cerebral Palsy Functional Impact Scale. Arm GDRS scores correlated with functional impact on the upper extremity task (linear regression R2 = 0.48, P = .0005). Leg GDRS scores correlated with gait impact (R2 = 0.43, P = .001). A 4-point increase in total GDRS corresponded to a 1-point worsening in combined functional impact. By demonstrating how expert-rated limb dystonia severity correlates with functional impact in children with CP, these results could help clinically identify functionally meaningful differences in dystonia severity.