Cross-cultural adaptation of the SWAL-QOL and the Sydney Swallow Questionnaire (SSQ) into French-Canadian and preliminary assessment for their use in an oculopharyngeal muscular dystrophy (OPMD) population

Abstract

Purpose. Patient-reported outcomes (PRO) assessing dysphagia are considered an essential component of clinical trials to consider how patients feel and function in response to treatments. The selected PRO needs to be translated in several languages using a systematic process ensuring its validity and equivalence for use in multicenter clinical trials. The main objective was to conduct the French-Canadian cross-cultural adaptation of the SWAL-QOL (FC SWAL-QOL) and the SSQ (FC SSQ) among an oculopharyngeal muscular dystrophy (OPMD) population.Methods. The principles of the International Society for Pharmacoeconomics and Outcomes Research Task Force method were followed for the FC SWAL-QOL and the FC SSQ. Cognitive interviews were conducted with 28 participants with OPMD. Known groups validity was assessed by comparison of the FC SWAL-QOL and the FC SSQ scores between groups of participants with OPMD known to differ in dysphagia severity, according to their drinking test score (n=21).Results. Equivalence issues were addressed during the cognitive interviews. Scores on the FC SSQ differed between the two groups divided by drinking test scores suggesting good known groups validity.Only two scales of the FC SWAL-QOL showed known group validity; the difference in the mean composite score was not signi cant, but this could be due to the small sample size. Conclusion:The SWAL-QOL and the SSQ were successfully translated into French-Canadian and adapted to an OPMD population. Additional validation should be considered depending on the intended population. The FC SSQ was better at discriminating dysphagia severity in a small sample size of OPMD participants. Introduction/backgroundOculopharyngeal muscular dystrophy (OPMD) is a progressive neuromuscular disease with a wide international distribution, but with the largest number of cases found in the Canadian province of Quebec due to a genetic founder effect [1][2][3]. Major symptoms include eyelid ptosis, oropharyngeal dysphagia and proximal limb weakness. Swallowing di culties typically appear after age 45 initially with solid foods and later with liquids [4][5][6]. Oropharyngeal dysphagia in OPMD may be assessed by a variety of semi-quantitative tests, such as manometry and video uoroscopy, and patient-reported outcomes (PRO) questionnaires [7]. PROs are increasingly used and recommended as endpoints in clinical trials, to supplement performance-based measures and laboratory tests [8]. In the eld of dysphagia, there are a number of PRO questionnaires differing by their evaluation purpose, psychometric properties and target populations [9,10]. However, these questionnaires are not speci cally designed to assess oropharyngeal dysphagia in OPMD and do not cover the entire symptom spectrum [11]. Two questionnaires, the Swallowing Quality of Life instrument (SWAL-QOL) and the Sydney Swallow Questionnaire (SSQ), were found to have at least some evidence of content validity for OPMD [11] and therefore were chosen to be pretested as two potential outcome measures for use in clini...