Nerve stimulation boosts botulinum toxin action in spasticity.

Spasticity leads to functional and structural changes in nerves and muscles, which alter skeletal muscle function. To evaluate whether short-term electrical nerve stimulation (NS) improves the effect of botulinum toxin in spastic skeletal muscle, we studied changes in the amplitude of the compound muscle action potential (CMAP) recorded from the extensor digitorum brevis (EDB) muscle in response to peroneal nerve stimulation at the ankle after injection of botulinum toxin type A (BTXA) alone or combined with short-term NS. In paraparetic patients, both EDB muscles were injected with BTXA; and NS was applied to one EDB muscle alone.