Visuoperceptual analysis of the videofluoroscopic study of swallowing: an international Delphi study

Introduction The Videofluoroscopic Swallow Study (VFSS) is a commonly used dysphagia assessment that is routinely analysed visuoperceptually. However, no consensus exists regarding which visuoperceptual measures should be used to analyse VFSSs. Current visuoperceptual measures for VFSSs are limited by poor quality and incomplete or indeterminate psychometric properties. Objective This study aimed to establish the content validity for a new visuoperceptual VFSS measure for oropharyngeal dysphagia in adults, by identifying relevant domains of the construct and generating items and corresponding response scales. Methods Consensus among experts in dysphagia and VFSS from over 20 countries was achieved across three rounds of anonymous online surveys, using the Delphi technique. Participants judged relevance and comprehensiveness of definitions of visuoperceptual domains of VFSS and the relevance of various domains to the overall construct. After reaching consensus on definitions of relevant domains, consensus on items were established using the same process. Results Participants achieved consensus on definitions of 32 domains recommended for analysis, and at least one item per domain (range 1-4). Domains selected by participants included both those which occur in existing measures and domains which have not been included in any measures to date. This study will form the basis for content validity of a new measure for VFSS. Conclusions This first phase of developing a visuoperceptual measure of VFSS resulted in the identification of 32 domains and 60 items for oropharyngeal dysphagia. Developers can now advance to the next phase of measure construction; prototype development and psychometric testing.Otorhinolaryngolog