Introducing the Dysphagiameter: a novel patient-reported outcome measure for evaluating dysphagia in oculopharyngeal muscular dystrophy - from conceptual framework to initial development.

Oculopharyngeal muscular dystrophy (OPMD) is a rare late-onset muscle disease associated with progressive dysphagia. As there was no patient-reported outcome measure specific for the assessment of dysphagia in OPMD, the Dysphagiameter was developed. The Food and Drug Administration guidance was followed. In Phase 1, a systematic literature review and an expert consultation were conducted to identify the concepts of interest. It was decided that the instrument should assess difficulty swallowing using pictures of foods of various textures (part A) and impact of dysphagia on activities and participation (part B), as defined by the International Classification of Functioning, Disability and Health. In Phase 2, focus groups (n = 3) and online surveys (n = 55) were conducted to generate the items. Then, the food items for part A were selected and grouped into 17 textures by a panel of registered dietitians. Cognitive interviews were conducted (n = 23) to refine the instrument and assess its clarity and comprehensiveness. The final draft included 82 food items assessing the capacity to swallow foods and drinks (part A) and 10 items assessing the impact of dysphagia on activities and participation (part B). Item reduction and assessment of psychometrics properties, using Rasch analysis, are ongoing as part of Phase 3.