The effect of short-term treatment with botulinum toxin a on muscle stiffness in stroke patients: an exploratory study

OBJECTIVE: To examine whether muscle stiffness -changes occur after botulinum toxin A treatment measured with shear wave elastography over a 3-month period and whether these changes are associated with walking function, active and passive ankle dorsiflexion, and participants' goal achievements.

DESIGN: Prospective cohort study.

SUBJECTS/PATIENTS: 25 first stroke survivors with disabling spasticity and reduced walking function (mean age 52.6).

METHODS: Botulinum toxin A was administered in relevant calf muscles. Muscle stiffness measurements with shear wave elastography and clinical tests such as spasticity test (Modified Ashworth scale), maximal active and passive dorsiflexion of the ankle, and 10 m walk test were conducted at baseline, after 6 weeks, and after 3 months. Medial gastrocnemius muscle stiffness was measured in both the affected and the unaffected leg. The Goal Attainment Scale was used to evaluate therapy goal achievements.

RESULTS: Significantly reduced muscle stiffness was found at 6 weeks on the affected side, but not at 3 months, and no changes were present on the unaffected side. A moderate positive correlation between muscle stiffness and Goal Attainment Scale score was observed.

CONCLUSION: Shear wave elastography could evaluate the effect of botulinum toxin A on muscle stiffness in stroke patients over a 3-month period. The correlation between muscle stiffness changes, goal attainment, and function need further longitudinal studies.