Dose-dependent response to intramuscular botulinum toxin type A for upper-limb spasticity in patients after a stroke.

OBJECTIVE: To test the hypothesis that intramuscular (IM) botulinum toxin type A (BTX) reduces excessive muscle tone in a dose-dependent manner in the elbow, wrist, and fingers of patients who experience spasticity after a stroke.

DESIGN: Randomized, double-blind, placebo-controlled, multicenter, 24-week trial.

SETTING: Six academic and 13 private US outpatient medical centers.

PARTICIPANTS: Ninety-one patients with a mean age of 60 years (range, 30-79 y). Mean time elapsed from ischemic or hemorrhagic stroke to study enrollment was 25.8 months (range, 0.9-226.9 mo).

INTERVENTIONS: Up to 2 treatments of placebo, or 90, 180, or 360U of BTX. Concurrent splinting and physical therapy protocols were permitted, but no changes were allowed during the study.

MAIN OUTCOME MEASURES: Wrist, elbow, and finger flexor tone assessed by the Modified Ashworth Scale, physician and patient global assessments, pain, FIM instrument, and Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36).

RESULTS: Muscle tone decreased more with injections of BTX than with placebo in the wrist flexors at weeks 1, 2, 3, 6, and 9 (P< or =.026); in the elbow flexors at weeks 1, 2, 3, 4, 5, and 9 (P< or =.033); and in the finger flexors at weeks 1 and 3 (P< or =.031). A dose-dependent response was generally observed in tone reduction but not in pain, FIM, or SF-36 measures.

CONCLUSIONS: IM BTX reduced muscle tone in a dose-dependent manner in the elbow, wrist, and fingers of patients who experience spasticity after a stroke but did not appear to affect global quality of life or disability.