A Swedish Population‐Based Study Found That Muscle Hypertonia in Children With Cerebral Palsy Varied by Age, Subtype, Functional Level, and Muscle Group

ABSTRACT Aim We examined how lower limb muscle tone was related to age, sex, Gross Motor Function Classification System (GMFCS) level, and the cerebral palsy (CP) subtype in Swedish children with CP. Methods This registry‐based cohort study from 2023 to 2024 used data on all 3 216 children aged 1–15 from the Swedish follow‐up program and national CP Registry. Muscle tone was assessed with the Ashworth Scale in the gastrocsoleus, hamstring, and adductor muscles. Associations between muscle tone and age, GMFCS level, sex, and CP subtype were analysed using descriptive statistics and logistic regression. Results Hypertonia, defined as Ashworth grade ≥ 1, was present in the gastrocsoleus in 84% of the children, in the hamstrings in 52%, and in the adductors in 34%. Prevalence increased with higher GMFCS levels and varied across age and muscle groups. Gastrocsoleus hypertonia peaked at 7–9 years and then declined. Hamstring hypertonia increased steadily up to 13–15 years. Adductor hypertonia showed a U‐shaped pattern across age groups. Children with bilateral spastic or dyskinetic CP had the highest hypertonia levels in all muscle groups. Conclusion Muscle hypertonia in children with CP varied by age, GMFCS level, CP subtype, and muscle group. This should be considered when planning treatment strategies.