Transmission within several spinal pathways in adults with cerebral palsy.

Many studies have investigated the changes of spinal neuronal networks in patients with cortico-subcortical or spinal lesions occurring during adulthood. In contrast, little is known about modifications of transmission within spinal networks implied in motor control for patients suffering from perinatal lesions. In the present series of experiments, we have investigated, in adult patients with cerebral palsy who suffered cerebral damage in the perinatal period, the efficacy of transmission within four spinal networks known for exhibiting pathophysiological changes following a central nervous system lesion occurring in adulthood. These are presynaptic Ia inhibition, post-activation depression, disynaptic reciprocal Ia inhibition and propriospinally-mediated Group I and Group II facilitations. In 28 patients with cerebral palsy and 35 age-matched healthy subjects we were able to show that: (i) disynaptic reciprocal Ia inhibition is intact in patients with cerebral palsy; (ii) both presynaptic Ia inhibition and post-activation depression are impaired in patients with cerebral palsy; and (iii) propriospinally-mediated Group I facilitation is undamaged in patients with cerebral palsy, whereas Group II facilitation is strongly enhanced. Only diminished post-activation depression was highly correlated to the severity of spasticity. Differences in the spinal transmission between patients with cerebral palsy and patients who suffered neuronal damage in adulthood are discussed.