PATTERNS OF CENTRAL MOTOR REORGANIZATION IN HEMIPLEGIC CEREBRAL-PALSY

Central motor reorganization was studied in 33 subjects with hemiplegi c cerebral palsy. Corticospinal projections were investigated using fo cal magnetic stimulation of the motor cortex. Reflex pathways were exa mined with digital nerve stimulation. Cross-correlation analysis of mu lti-unit EMG was used to detect activity in branched common stem last order presynaptic inputs to motor neuron pools. The neurophysiological findings were related to the clinical outcome. In 21 of the subjects studied (64%), there was evidence for reorganization of central motor pathways. The clinical and neurophysiological findings revealed two di fferent forms of reorganization. In both forms focal magnetic stimulat ion demonstrated novel ipsilateral motor pathways from the undamaged m otor cortex to the hemiplegic hand. Ipsilateral projections were not d emonstrated from the damaged motor cortex. Eleven subjects had intense minor movements. In these subjects cross-correlation analysis and ref lex testing suggested that corticospinal axons had branched abnormally and projected bilaterally to homologous motor neuron pools on both si des of the spinal cord. The remaining 10 subjects did not have intense mirror movements and in these subjects there was no evidence for last order branching of corticospinal axons. It was found that good functi on of the hemiplegic hand was associated with the presence of EMG resp onses in that hand following magnetic stimulation of the contralateral motor cortex. When EMG responses were absent, hand function was poor unless the subject had intense mirror movements.