Modification of altered ankle motor control after stroke using focal application of Botulinum toxin type A

Study design: Blinded, placebo-controlled, prospective clinical trial. Purpose: To examine the effects of botulinum toxin type A (BTX-A) injections into plantar flexor muscles in stroke patients with equinovarus gait. Subjects: 15 post-stroke and 10 matched neurologically intact subjects. Methods: Modified Ashworth Scale (MAS) and Fugl-Meyer assessment of physical function scale scores along with surface EMG collected before and up to 12 weeks after BTX-A injections to plantar flexor muscle motor points in stroke subjects. Saline placebo injections were performed in a subset of stroke subject group. Results: MAS scores were decreased at 4, 8 and 12 weeks but F-M scores did not improve until 12 weeks post injection. Multi-muscle EMG patterns showed the return of volitional dorsiflexor activity in 11 and a decrease of antagonistic and distant coactivation in all but one of the 15. Conclusions: BTX-A is effective in reducing antagonistic and distant muscle activation that impedes volitional dorsiflexion.