Enzyme replacement therapy for MPS I: When is the right time to stop?

To assess the effects of injecting botulinum toxin into the lower limb muscles of people with hemiparesis post stroke in terms of their sway areas.A multicenter randomized double-blind trial on the effects of active botulinum toxin treatment vs placebo.Clinical examinations and postural sway assessments were performed before botulinum toxin injection and again 4-6 weeks after the injection.People with hemiparesis with chronic post stroke lower limb spasticity (N=40).Intramuscular injection of a placebo (physiological serum) was performed on the control group, and botulinum toxin injections were performed on the treatment group. Participants and physical and rehabilitation medicine specialists were given no information as to which of the 2 treatments was applied.The sway area of the center of pressure was recorded for 30 seconds in 3 conditions: eyes open, eyes open in a dual task (a postural control task combined with an arithmetic task), and eyes closed. Spasticity was measured using the Modified Ashworth Scale.Forty people post stroke were enrolled and randomized into 2 groups, one of which was treated with botulinum toxin (n=19) and the other with placebo (n=21). Spasticity decreased significantly in the treatment group (−0.7, P=.049 in the soleus muscles; −0.8, P=.035 in the gastrocnemii muscles). The sway area did not differ significantly between the 2 groups before treatment. The most conspicuous effect was observed in the case of the dual task, where a significant decrease (P=.005) in the sway area occurred in the treatment group (−3.11±6.92) in comparison with the placebo group (+0.27±3.57).Treating spasticity by injecting botulinum toxin into people’s lower limb muscles post stroke seems to improve their postural sway. The dual task used here to assess sway seems to be a useful, sensitive test for this purpose.