EMG-based characterization of walking asymmetry in children with mild hemiplegic cerebral palsy

Hemiplegia is a neurological disorder, detected in children with cerebral palsy. Although many studies investigated muscular activity in hemiplegic leg, few EMG-based findings focused on unaffected limb. The study aimed to quantify the asymmetric behavior of lower-limb-muscle recruitment during walking in mild-hemiplegic children from surface-EMG and foot-floor-contact features. sEMG signals from tibialis anterior (TA) and gastrocnemius lateralis and foot-floor-contact data during walking were analyzed in 16 hemiplegic children classified as W1 according to Winter’ scale, and in 100 control children. Statistical gait analysis, a methodology achieving a statistical characterization of gait by averaging surface-EMG-based features, was performed. Results, achieved in hundreds of strides for each child, indicated that in hemiplegic side with respect to non-hemiplegic side, W1 children showed a statistically significant: decreased number of strides with normal foot-floor contact; decreased stance-phase length and initial-contact sub-phase; curtailed, less frequent TA activity in terminal swing and a lack of TA activity at heel-strike. The acknowledged impairment of anti-phase eccentric control of dorsi-flexors was confirmed in hemiplegic side, but not in contralateral one. However, a modified foot-floor-contact pattern is evinced also in the contralateral side, probably to make up for balance requirements.