Reconstructing the Rasch-Built Myotonic Dystrophy Type 1 Activity and Participation Scale
Fig 1
External construct convergent validity and test-retest reliability for DM1-ActivC.
The 25-item DM1-ActivC scale demonstrates high external construct/convergent validity with the 20-items DM1-Activ (A). Patients’ ability (B) and items’ difficulty hierarchy (C) in the first and second assessment are located within the 95% confidence intervals indicating ideal invariance (solid lines).