Yes, in the paper referenced in the studies (Figure 1a):The SF-36 scores don't seem like something they would be normally distributed. Has anyone ever plotted the probability density function or done a test for normality? If it's not, parametric measures to define recovery such as standard deviation would be inappropriate without some transformation of the data.
Results were similar across all six samples. Kolmogorov–Smirnov tests were also highly significant for each of the eight domains, and are shown in Table 2. These results confirm the highly skewed nature of the distributions (see Fig. 1), which is a problematic feature of all health status scales.