Impact of Body-Height Increase on Gastrocnemius Muscle Stiffness in Children With Cerebral Palsy: A one-year Prospective Cohort Study.

Abstract

The aim of the study was to investigate whether the impacts of height increase on gastrocnemius muscle stiffness are greater in children with spastic cerebral palsy than in those with typical development. This 1-yr cohort study enrolled children (cerebral palsy, 23; typical development, 23) who underwent two measurements conducted at entry and after 1 yr. Lateral and medial gastrocnemius muscle-strain ratios representing muscle stiffness were obtained using elastography. All regression equations (dependent variable, rate of change of height; independent variable, rate of change of the gastrocnemius muscle-strain ratios) were significant and all R2 s in children with cerebral palsy (all P < 0.001; lateral gastrocnemius muscle's R2 = 0.81; medial gastrocnemius muscle's R2 = 0.74) were greater than those in children with typical development ( P < 0.001 and R2 = 0.49; medial gastrocnemius muscle's R2 = 0.49). The coefficients of equations in children with cerebral palsy were significantly larger than those in typical development ( P < 0.05). The greater R2 values in cerebral palsy than typical development could explain how the variation in height predicts the variations in gastrocnemius muscle stiffness more accurately in cerebral palsy than in typical development. Gastrocnemius muscle stiffness worsens more in children with cerebral palsy than that in typical development.