Objective:

To examine the degree of muscle tone in different lower limb muscle groups in children with cerebral palsy (CP) in relation to age, Gross Motor Function Classification System (GMFCS) level, and CP subtype, highlighting the importance of these factors in understanding muscle tone distribution.

Approach:

• Study Design: A population-based registry study using data from the Swedish combined follow-up program and national CP Registry (CPUP) involving 3,216 children with CP aged up to 15 years.
• Data Collection: Data on muscle tone was collected through standardized assessments using the Modified Ashworth Scale (AS) and classified by GMFCS levels.
• Analysis: Logistic regression was used to analyze the relationship between muscle tone and variables such as age, sex, CP subtype, and GMFCS level.

Key Findings:

• 82% of children exhibited muscle hypertonia in the gastrocsoleus muscles, 50% in the hamstring muscles, and 34% in the adductor muscles.
• The prevalence and severity of hypertonia increased with higher GMFCS levels across all muscle groups.
• No statistically significant difference in muscle tone levels was found between sexes.

Interpretation:

The study reports the prevalence of muscle hypertonia in children with CP and its correlation with functional levels as classified by GMFCS.

Limitations:

• The study excluded children who had undergone selective dorsal rhizotomy or had intrathecal baclofen pumps.
• CP subtype data was missing for 26% of the children.

Conclusion:

The findings provide insights into the distribution of muscle tone in children with CP.