NEURAL AND MUSCULOSKELETAL CONTRIBUTIONS TO THE DEVELOPMENT OF STANCEBALANCE CONTROL IN TYPICAL CHILDREN AND IN CHILDREN WITH CEREBRAL-PALSY

Studies on the development of automatic postural responses in both typ ically developing children and children with cerebral palsy were perfo rmed. With the appearance of ''pull-to-stand'' behavior, typically dev eloping children first began to show muscle responses to platform move ments in mainly the ankle muscles. With increased development, additio nal agonist muscles were added to the response pattern and a consisten t distal to proximal sequence began to emerge. Well-organized response s were seen with the onset of independent stance and walking, along wi th the reduction of antagonist muscle co-activation. The older childre n with cerebral palsy who were pre-walkers had immature muscle activat ion patterns like those seen in the typically developing children at t he pull-to-stand stage of development. These included disorganized mus cle responses and increased frequency of coactivation of both proximal -distal and agonist-antagonist muscles. In order to determine if muscu loskeletal constraints contributed to these response pattens, normal c hildren were asked to stand in a crouched posture similar to that of c hildren with CP. This caused postural muscle response patterns to more closely approximate those of children with spastic diplegia.