TABLE 2.
Effect size coefficient and estimated sample size for clinical and Actigraph variables.
| SRM | Sample size per treatment arm | |
|---|---|---|
| SARA score | 0.98 | 22 |
| mFARS score | 0.16 | 618 |
| ADL | 0.39 | 108 |
| CCFS | 0.09 | 1940 |
| 8MWT | 0.29 | 194 |
| Metabolic Equivalent of Task rate | ||
| Waist | 0.33 | 150 |
| wrist | 0.34 | 140 |
| N. of activity bouts | ||
| Waist | 0.27 | 220 |
| wrist | 0.43 | 90 |
| % sedentary | ||
| Waist | 0.69 | 38 |
| wrist | 0.36 | 126 |
| % Moderate-Vigorous physical activity | ||
| Waist | 0.59 | 50 |
| wrist | 0.51 | 66 |
| VM3 (CPM) | ||
| Waist | 0.79 | 30 |
| wrist | 0.46 | 80 |
| Steps/minute | ||
| Waist | 0.54 | 58 |
| wrist | 0.51 | 66 |
Sample size per treatment arm is calculated for 1-year study comparing two treatment groups, with 80% power and α = 0.05. SRM: standardized response mean; SARA: Scale for the Assessment and Rating of Ataxia. mFARS: modified Friedreich Ataxia Rating Scale; ADL: Activity of Daily Living part of FARS; CCFS: cerebellar composite functional severity score; 8MWT: 8 m walk test (seconds); n.a.: not assessed; VM3 CPM: vector magnitude counts per minute.