# Validation and Interpretation of the Persian Version of the Swallowing Disturbance Questionnaire in Patients with Multiple Sclerosis

## TL;DR

This study validates a Persian version of a questionnaire to detect swallowing issues in multiple sclerosis patients, showing it is reliable and effective.

## Contribution

The Persian version of the Swallowing Disturbance Questionnaire is validated for use in multiple sclerosis patients for the first time.

## Key findings

- The Persian SDQ has high internal consistency with a Cronbach’s alpha of 0.913.
- The questionnaire strongly correlates with the DYMUS and EDSS measures.
- The SDQ demonstrated high screening power with 91.7% sensitivity and 88.9% specificity.

## Abstract

Background: Patients with multiple sclerosis (PwMS) frequently experience dysphagia, which affects their quality of life. The swallowing disturbance questionnaire (SDQ) has demonstrated potential in screening dysphagia in different disorders. The objective of this study was to evaluate the validity and reliability of the Persian version of SDQ in PwMS. Methods: In this cross-sectional study, 198 PwMS were enrolled. The translation of SDQ into Persian was performed using the forward–backward method. Participants completed both the SDQ and the Dysphagia in Multiple Sclerosis (DYMUS) questionnaires. Convergent validity was assessed using the Spearman correlation, construct validity was evaluated by principal component analysis (PCA), and reliability was assessed by Cronbach’s alpha. Screening ability was evaluated with receiver operating characteristic (ROC) curve analysis, using DYMUS as the reference measure. Results: The Persian SDQ showed high internal consistency (Cronbach’s alpha = 0.913) after removing one item. PCA revealed a single dominant factor accounting for 49.4% of the variance. The 14-item SDQ correlated strongly with both DYMUS (Spearman’s rho = 0.62, p < 0.001) and Expanded Disability Status Scale (EDSS) (Spearman’s rho = 0.388, p < 0.001). The area under the curve of 0.957 revealed high screening power with a sensitivity of 91.7% and a specificity of 88.9%. Conclusions: The Persian SDQ is a valid and reliable tool for early detection and quick monitoring of dysphagia in PwMS.