Clinical utility of a patient-reported outcome for assessing spasticity in a pediatric population.

PurposeThis study aimed to (1) examine the construct validity of the Zorowitz spasticity patient-reported outcome (PRO) scale in pediatric populations and (2) examine the scale's responsiveness to change in children to determine its clinical utility in guiding treatment of pediatric spasticity.MethodsRetrospective analysis of data collected at a large academic pediatric hospital system, including 505 patients who received injections for spasticity from pediatric physiatrists, was performed. Zorowitz scores, spasticity (Modified Ashworth Scale) scores, and Gross Motor Function Classification System levels were extracted.ResultsBaseline Zorowitz score (median 19, interquartile range 13-25) was not related to functional level (r = -0.088, p = 0.20) nor muscle tone (r = 0.006, p = 0.95), but patients with follow-up data reported reduced impact of spasticity post-injection (p < 0.0001). Higher baseline Zorowitz score was related to a greater decrease in Zorowitz score after injection (r = -0.39, p < 0.00001). Injection location, sex, number of muscles injected, and botulinum toxin dose were not related to Zorowitz change score.ConclusionThe Zorowitz scale may be responsive to spasticity treatment in children. However, construct validity to existing clinical measures was not observed, suggesting either that a clinical gold standard does not exist, that the scale measures a construct not otherwise captured clinically, or that it has limited validity in children.