POSTURAL CONTROL IN CHILDREN WITH SPASTIC DIPLEGIA - MUSCLE-ACTIVITY DURING PERTURBATIONS IN SITTING

To clarify the neural mechanisms controlling equilibrium during sittin g, and the implications for the optimal sitting position for children with CP, automatic postural adjustments after perturbations of the sup port surface during sitting were investigated in seven children with s pastic diplegia and in seven age-matched controls. A sudden backward s way of the body evoked brisk responses in 'ventral' muscles in both gr oups. However, the order of muscle recruitment, which in most nondisab led children was caudal to cranial, was reversed in the children with diplegia, whose first response was in the neck flexors. The children w ith diplegia also co-activated antagonistic neck and hip muscles. The authors concluded that although children with spastic diplegia may pro duce a basic muscle activation pattern (first level of the central pat tern generator, CPG), they cannot adjust the pattern in response to ex ternal changes (second level of the CPG).