We thank Dr Pincus for his interest in our study and appreciate the opportunity to expand on the data presented in the article.
Of the 11 subjects we studied, 7 increased their walking speed after pallidotomy, while 4 walked at the same speed or slightly slower.1 For precisely this reason, we presented the data in Figure 1 to allow readers to see the individual data on which the statistical analyses were based. Unfortunately, we were unable to explain the lack of postoperative improvement from any preoperative or surgical lesion information. Statistical testing compared mean data; however, similar findings were noted with median data, which are unaffected by extreme values.2 In particular, median walking speed was 0.19 statures per second preoperatively and 0.48 statures per second postoperatively, an even larger increase than reflected in the mean data.
Siegel KL, Metman LV. Beneficial Effect of Bilateral Pallidotomy on Gait Is Unproven—Reply. Arch Neurol. 2000;57(8):1231. doi: