Abstract

Objective
To investigate the electrophysiological changes after botulinum toxin type A injection in children with cerebral palsy. Method: Sixteen children with spastic cerebral palsy enrolled in the study. Botulinum toxin type A (Dysport^Ⱂ) was injected into gastrocnemius muscles. Electrophysiological assessments included the compound motor action potential of the tibial nerve, the sensory nerve action potential of the sural nerve, the H-reflex and the T-reflex before injection, and at 2 weeks and 4 weeks after the injection. Modified Ashworth scale was used to evaluate spasticity before, 2 weeks and 4 weeks after the injection. Results: Modified Ashworth scale of the ankle decreased at 2 weeks and 4 weeks after injection. The amplitude of the H-reflex and H_max/M_max ratio decreased significantly at 4 weeks. The amplitude of the T-reflex decreased at 2 weeks and 4 weeks. The correlation between changes in modified Ashworth scale of the ankle and the changes in electrophysiological parameters at 4 weeks after injection were not significant. Conclusion: The change in T-reflex is faster than the change of H-reflex and H_max/M_max ratio after botulinum toxin A injection in children with cerebral palsy. Electrophysiological tests could quantify the change in spasticity after botulinum toxin injection. (J Korean Acad Rehab Med 2010; 34: 179-184)

• Keywords: Cerebral palsy, Spasticity, Botulinum toxin, H-reflex, T-reflex