Table 2 Aspects of clinical validation for SV95C for Duchenne muscular dystrophy. 6MWD: 6 Minute Walk Distance, NSAA: North Star Ambulatory Assessment, 4SC: 4 Stair Climb

Known-groups validity

Compare median of digital outcome measure between patients with disease and healthy controls.

Median of SV95C in DMD population (1.583 m/s) was lower than that of age-matched healthy controls (2.713 m/s).

Convergent validity

Compute correlations between digital and traditional outcome measures.

Moderate correlations between SV95C and traditional outcomes were observed: 6MWD (0.542) , NSAA (0.645) and 4SC (0.547) at baseline. Similar results were observed at 3, 6, 9 and 12 month follow-ups.

Sensitivity to disease progression

Compute change in median of digital outcome measure between baseline and follow-up. Compare with traditional outcome measures.

A decline from baseline was established at 3 months for patients on a stable regimen of corticosteroids or having initiated corticosteroids from at least 6 months. SV95C was demonstrated to be more sensitive to disease progression than traditional outcome measures.

Sensitivity to change due to treatment

Calculate change in median of digital outcome measure in patients who have started on a treatment.

A positive change in median was observed for patients who were started on corticosteroids. Patients in two clinical trials investigating new medicinal interventions were followed up, but the interventions were shown not to be effective.