Topical anesthetics: effects on the Achilles tendon and H-reflexes. II. Stroke patients.

This study determined whether the Achilles tendon reflex, H-reflex, and ankle range of motion (ROM) during ambulation undergo significant changes after application of benzocaine spray applied to the triceps surae skin area of eight stroke patients displaying spasticity in ankle plantar flexor muscles. The H-reflex amplitude increased significantly (p less than 0.05) at 30 minutes after both the benzocaine (0.346 +/- 0.101V) and the placebo (air spray, 0.324 +/- 0.078V) when the placebo was given first; however, there was no significant difference between the two interventions. A significant decrease in ankle ROM occurred during midswing at 20 (placebo administered first) and 30 (benzocaine administered first) minutes after the placebo, but this decrease was not significantly greater than the change after the benzocaine. Benzocaine spray did not change motor neuron excitability level or improve the subject's ability to perform a functional task.