Validity and Reliability of the Turkish Version of the Questionnaire for the Assessment of Dysphagia in Multiple Sclerosis

Abstract
Introduction: The aim of this study was to investigate the validity and reliability of the Turkish version of the Questionnaire for the Assessment of DYsphagia in MUltiple Sclerosis (DYMUS) that has been developed for evaluating dysphagia in patients with multiple sclerosis. Methods: This methodological study was conducted in the neurology clinic and outpatient department of a training hospital between March 15 and September 15, 2015. The study included 117 patients aged 18 years and over who had a definite diagnosis of multiple sclerosis, could communicate in Turkish, and volunteered to be included. Data were collected using a descriptive information form, the DYMUS, and the Eating Assessment Tool (EAT-10). The scale was translated and back translated to determine the language validity, and a specialist was consulted to make sure the content was valid. We used the EAT-10 and Kurtzke's Expanded Disability Status Scale (EDSS) concurrently to test the criterion-related validity. The test-retest procedure was used at 1-week intervals for 37 patients in this study. Descriptive statistics, factor analysis, Kappa analysis, reliability analysis, and correlation analysis were used to analyze the data. Results: Factor analysis revealed that the scale was bifactorial, and this was consistent with its original form. There were positive and statistically significant relationships between the DYMUS and EAT 10 (r=0.90, p<0.001) and the mean EDSS scores (r=0.49, p<0.001). The internal consistency of the total scale was high (Cronbach's alpha coefficient= 0.91). The Cronbach's alpha coefficients pertaining to dysphagia for solids and liquids were determined to be 0.88 and 0.83, respectively. The total scale and subscales demonstrated a high test-retest reliability (r=0.79-0.95, p<0.001). Conclusion: In this study, the Turkish version of the DYMUS was found to be a valid and reliable tool for evaluating dysphagia in patients with multiple sclerosis.