Developmental medicine and child neurology
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Dev Med Child Neurol · Jun 2011
Moving towards meaningful measurement: Rasch analysis of the North Star Ambulatory Assessment in Duchenne muscular dystrophy.
Reliable measurement of disease progression and the effect of therapeutic interventions in Duchenne muscular dystrophy (DMD) require clinically meaningful and scientifically sound rating scales. Therefore, we need robust evidence to support such tools. The North Star Ambulatory Assessment (NSAA) is a promising, clinician-rated scale with potential uses spanning clinical practice and clinical trials. In this study, we used Rasch analysis to test its suitability in these roles as a measurement instrument. ⋯ In general, Rasch analysis supported the NSAA as a psychometrically robust scale for use in DMD clinical research and trials. This study also demonstrates how Rasch analysis is a useful instrument to detect and understand the key measurement issues of rating scales.