Muscle activation characteristics of stance balance control in children with spastic cerebral palsy

Two studies were conducted to investigate muscle recruitment of children wi th spastic cerebral palsy in response to unexpected perturbation of balance in stance. The aim of the studies was to investigate neural and non-neural mechanical contributions to muscle responses differences these children di splay when maintaining balance. In the first study, muscle responses of chi ldren with spastic diplegia were compared to typically developing children with similar levels of walking experience. Each child stood on a moveable p latform that was displaced backward. Electromyographic recordings of poster ior agonist and anterior antagonist muscles of the legs and trunk were anal yzed and compared to those of normal children who had obtained a similar de velopmental levels of mobility. Children with spastic cerebral palsy were f ound to have an increase in antagonist recruitment and decreased trunk acti vation when compared to typically developing children at the same level of walking experience. Developmental trends were noted to be similar in all ch ildren with or without pathology. As children gained independent walking sk ills, they demonstrated shorter onset latencies in leg and thigh muscles. I n the second study, older children with no pathology were perturbed in crou ch stance, simulating the posture of their matched children with cerebral p alsy. Changes in their muscle responses were observed to more clearly appro ximate the muscle onset latency organization of children with spastic diple gia. Results of these studies suggest that muscle recruitment differences f or balance control in children with spasticity are due to CNS deficits as w ell as mechanical changes in posture. (C) 1998 Elsevier Science B.V. All ri ghts reserved.