High-density EMG reveals atypical spatial activation of the gastrocnemius during walking in adolescents with Cerebral Palsy

Abstract

Children with Cerebral Palsy CP exhibit less-selective, simplified muscle activation during gait, due to injury of the developing brain. Abnormal motor unit recruitment, altered excitation-inhibition balance, muscle morphological changes all affect the electromyogram of CP muscle. High-density surface electromyography HDsEMG has potential to reveal novel manifestations of CP neuromuscular pathology, links with functional deficits by assessing spatiotemporal details of myoelectric activity. We used HDsEMG to investigate spatial-EMG distribution, temporal-EMG complexity of the gastrocnemius medialis GM muscle during treadmill walking in 11 adolescents with CP, 11 typically developed TD adolescents.

Our results revealed more-uniform spatial-EMG amplitude distribution across the GM in adolescents with CP, compared to distal emphasis in TD adolescents. More-uniform spatial-EMG was associated with stronger ankle co-contraction and spasticity. CP adolescents exhibited a non-significant trend towards elevated EMG-temporal complexity. Homogenous spatial distribution and disordered temporal evolution of myoelectric activity in CP suggests less-structured and desynchronized recruitment of GM motor units, in combination with muscle morphological changes. Using HDsEMG, we uncovered novel evidence of atypical spatiotemporal activation during gait in CP, opening paths towards deeper understanding of motor control deficits and better characterization of changes in muscular activation resulting from interventions.