Comment on "prevalence and risk factors of dysphagia in patients with multiple sclerosis".

We read the recent interesting article entitled "Prevalence and Risk Factors of Dysphagia in Patients with Multiple Sclerosis," published in Dysphagia on February 2021. We believe the discussion part of this study could have provided further and more precise interpretations regarding its results. Thus, we would also like to comment our inferences in accordance with its results to highlight some essential points.

Persian Translation, Validation and Reliability of the Voice Handicap Index-Throat (VHI-T).

OBJECTIVE: The aim of the present study is to validate, and assess the reliability of the Persian version of Voice Handicap Index-Throat (VHI-Tp) as a self-reported questionnaire for patients with throat problems that could make the patients' estimation of the throat discomforts possible. It is a subscale to be used independently. STUDY DESIGN: This is a cross-sectional study. MATERIALS AND METHOD: During this study, the VHI-Tp was administered to120 patients with throat problems related to laryngeal discomfort (51 male and 69 female, age range: 30-60 years).The diagnosis of Voice disorder was performed by an ENT physician based on video-laryngoscopy evidences and medical examination. To assess the content validity, the questions were first given to 15 experts to comment on content applicability and relevance through a Likert scale. Eighty patients rated its importance to detect face validity. To evaluate the concurrent validity, the same 80 patients completed both the VHI-Tp as well as the Persian version of Voice Symptom Scale. The VHI-Tp total scores of the patients with diagnosed throat problem related to laryngeal discomfort and of the 40 healthy participants were compared to test the clinical validity (discriminant validity). Also, internal consistency reliability was assessed using Cronbach α coefficient. The relative reliability was calculated by asking 40 of all patients out of the 80 participants, to complete the VHI-Tp twice, with a week of interval between the first and the second times. To detect the absolute reliability, Standard Error of Measurement and Smallest Detected Change were calculated. RESULTS: Discriminative validity differed significantly between patients and healthy participants. There was a significant correlation between the VHI-Tp and Voice Symptom Scale total scores (r = 0.6, P < 0.05). The internal consistency was confirmed (Cronbach α = 0.78). The test-retest reliability was excellent (intraclass correlation coefficient = 0.95).The Standard Error of Measurement and Smallest Detected Changes were acceptable (0.39 and 1.08), respectively. CONCLUSION: The Persian version of the VHI-T was demonstrated to be a valid and reliable self-rated questionnaire for use in Persian patients with throat problem related to laryngeal discomfort.