Effect of BTX-A on hand function. The effect of BTX-A on hand function when compared to placebo was investigated using a random effects model. Tsui et al. (1993) did not report results in the placebo group and therefore these data could not be included in this meta-analysis. The events shown here represent self-reported benefit of BTX-A on hand function. BTX-A = Botulinum Toxin Subtype A; CI = Confidence Interval; M-H = Mantel-Haenszel test; df = degrees of freedom.