Electrophysiological assessment of the effect of intrathecal baclofen in spastic children

Objectives: To evaluate the effect of intrathecal baclofen in a group of spastic children using electrophysiological procedures described in adults. Methods: Six children (aged 1-14 years) with severe spasticity of various aetiologies underwent transcranial magnetic stimulation, H reflex and flexor reflex studies before and after intrathecal injection of baclofen. Ashworth scale was used for clinical evaluation of spasticity. Results: Motor evoked potentials, present in two patients before baclofen, were preserved after injection. Before baclofen, H reflex was present in 5 patients (H-max/M-max from 0.23 to 0.84) and absent in one who had infantile neuroaxonal dystrophy. After baclofen, it was absent in 4 patients and markedly reduced in one. Surface of flexor reflex significantly decreased after baclofen (P = 0.01), while threshold significantly increased (P = 0.003). Conclusions: In spastic children, the action of baclofen on spinal pathways may be quantified by the same electrophysiological procedures as in adults. This approach may contribute to select optimal dosage. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.