Table 2.
Summary of the weighted mean percentage improvement(s) (WMP). Based on Gross et al. [24]
| Factors | Study groups | Combined Sample Size (Ni) | Weighted Mean Percentage Improvement (WMP) |
| A | Active groups in open-trials | 41 | 33.7 |
| B | Active groups SPTs | 148 | 15.9 |
| A-B | Difference between the active groups under the two trial conditions | – | 17.8 |
| C | Sham controls in SPTs | 125 | 10.1 |
| B-C | Estimated effect size in SPTs | – | 5.8 |
| D | Unoperated controls | 0 | No results |
| C-D | Difference between placebo groups and unopened controls | 0 | No results |
Combined Sample Size (Ni) represents the number of participant in each of treatment categories, as defined in Fig. 1.