Cross-Cultural Adaptation and Validation of the Malayalam Version of the Vocal Tract Discomfort Scale

Background: Voice disorders significantly impact individuals' physical, functional, and emotional well-being, necessitating comprehensive assessment tools. The Vocal Tract Discomfort Scale (VTDS) assesses the frequency and severity of vocal discomfort symptoms. Despite its global adaptations, no validated Malayalam version has existed. This study aimed to adapt and validate the VTDS for Malayalam speakers (VTDS-M). Method: The study was conducted in two phases: Phase I involved translation and cultural adaptation of VTDS into Malayalam, followed by content validation by native-speaking speech language pathologists; Phase II involved validation of VTDS-M on 150 professional voice users, categorized into normophonic (n = 105) and dysphonic (n = 45) groups based on otolaryngological and perceptual voice evaluations. Participants completed VTDS-M and VHI-M (Voice Handicap Index-Malayalam). Results: The results showed strong internal consistency (Cronbach's α = 0.827 for frequency, 0.813 for severity). Significant differences were observed between groups for VTDS-M subscales and total scores, confirming its discriminatory capability. ROC analysis established a cut-off score of 11.5, with an AROC of 0.749, 64.4% sensitivity, and 79.0% specificity. Also, VTDS-M correlated positively with VHI-M, especially the physical and emotional subscales. Conclusions: VTDS-M demonstrated reliable psychometric properties and diagnostic accuracy, making it a valuable tool for assessing vocal discomfort in Malayalam-speaking populations specifically among the professional voice users. Future studies should explore its applicability to non-professional voice users with varied severity levels of dysphonia.