Table 2.
Baseline, follow-up scores, and estimates of the sample sizes in PSP (N = 12) and MSA (N = 8).
| Baseline score | Repeat score | Annual change | Number of subjects required per arm (20% reduction) |
Number of subjects required per arm (50% reduction) |
|
|---|---|---|---|---|---|
| PSP | |||||
| Whole-brain atrophy rate, % | N/A† | N/A† | 1.26 ± 0.5 | 83 | 14 |
| UPDRS III | 37 ± 14.5 | 39.2 ± 19 | 2.3 ± 13 | 168 | 27 |
| CGI-S | 4.4 ± 0.5 | 4.6 ± 0.8 | 0.2 ± 0.6 | 4889 | 1048 |
| H&Y | 2.6 ± 0.7 | 3.3 ± 0.9∗ | 0.7 ± 0.8 | 631 | 101 |
| FAB | 10 ± 5.3 | 10.7 ± 7.8 | 0.7 ± 4.6 | 22688 | 3630 |
| MSA | |||||
| Whole-brain atrophy rate, % | N/A† | N/A† | 1.65 ± 1.1 | 234 | 38 |
| UPDRS III | 45.3 ± 13 | 52.6 ± 10 | 7.1 ± 9.4 | 921 | 148 |
| CGI-S | 4.6 ± 0.5 | 5.1 ± 3.5∗ | 0.5 ± 0.5 | 621 | 100 |
| H&Y | 3.1 ± 0.8 | 3.7 ± 0.4∗ | 0.7 ± 0.7 | 526 | 85 |
| FAB | 12.0 ± 4.2 | 10.8 ± 4.4 | −1.1 ± 3.4 | 5020 | 804 |
∗Difference between the baseline and repeat score with a p value < 0.05 (Wilcoxon's signed rank test). †SIENA gives the whole-brain atrophy rate for image pairs and does not estimate the baseline and follow-up brain volume. All of the values are the mean ± SD.