Development and cross-cultural adaptation of the vestibular disorders activities of daily living scale in the kannada language and testing its psychometric properties

Background: Vestibular Disorders Activities of Daily Living Scale (VADL) is a self-reported survey for assessing functions of individuals affected by vestibular disorders, and this survey has been translated and cross-culturally adapted into many languages. Objective: Kannada is one of the most-spoken languages in India, with approximately 64 million speakers. We aimed to develop the Kannada version of VADL and to assess its psychometric properties. Materials and Methods: The translation and adaptation of the English version of VADL into Kannada were accomplished with the input of medical professional language experts. Pretesting of the Kannada VADL (VADL-K) was conducted on 30 patients with vestibular disorders. Six professional experts with medical background provided their opinion during the content validation process of VADL-K, and 50 subjects aged between 30 and 70 years with variant vestibular disorders were administered VADL-K and the Dizziness Handicap Inventory to determine the internal consistency, test-retest reliability, and concurrent validity of this assessment. Results: This study effectively translated, adapted, and pretested VADL-K. The scale's content validity was 0.95, its internal consistency (Cronbach's alpha = α) was 0.94, its test-retest reliability with Intra Class- Correlation Coefficient was 0.97, and its concurrent validity in comparison with DHI was significant, with a moderate correlation r-value of 0.58. Conclusion: The English version of VADL was successfully translated and adapted into the Kannada language. VADL-K is a valid and reliable measure for patients with vestibular disorders in the state of Karnataka to report their functional performance.