Lower-limb joint-coordination and coordination variability during gait in children with cerebral palsy

Children with cerebral palsy present with poor motor control, altering their ability to perform tasks such as walking. Continuous relative phase analysis is a popular method to quantify motor control impairments via inter-joint coordination and coordination variability; however, it has not been explored in children with cerebral palsy.

45 children with cerebral palsy and 45 typically developing children walked while fit with retroreflective markers. Continuous relative phase analysis for knee-hip and ankle-knee joint pairs quantified inter-joint coordination and coordination variability. The Gait Profile Score estimated gait pathology. Group differences were assessed with unpaired t-tests for coordination amplitude and variability (knee-hip, ankle-knee) across gait events. For the cerebral palsy group, correlations assessed the relation between the gait profile score and coordination metrics.

The cerebral palsy group showed more in-phase patterns for knee-hip coupling compared to the typically developing group (initial contact, loading response, mid-stance, terminal swing) (p ≤ 0.03). The cerebral palsy group showed lower knee-hip coordination variability (mid-stance, mid-swing) (p ≤ 0.037) and lower ankle-knee coordination variability (initial contact, loading response, terminal swing) (p < 0.001). The gait profile score correlated weakly to moderately (r = [0.323-0.472]), and negatively with the knee-hip inter-joint coordination (initial contact, loading response, mid-stance, terminal swing) (p ≤ 0.042).

Children with cerebral palsy showed a more in-phase gait strategy during challenging transitional gait cycle phases (beginning and end) and less flexible and adaptable motor behaviors. Moreover, the correlation between in-phase joint patterns and increased gait deviations (gait profile score) reinforces the relevance of coordination analysis to assess motor control impairment.