Cross-cultural adaptation of the Thai Xerostomia Inventory and Summated Xerostomia Inventory

ObjectiveTo cross-culturally adapt and validate the Thai version of the Xerostomia Inventory (XI) and Summated Xerostomia Inventory (SXI) for subjective evaluation of oral dryness in Thai middle-aged and older adults.MethodsThe original English versions of the XI and SXI were cross-culturally translated into Thai. Content validity was examined by the expert panel and 30 pilot subjects. The XI/SXI-Thai were then administered to 200 Thai adults (aged 50 years or older) for further assessment of psychometric properties. The standard question, the Bother Index, and the Xerostomia Questionnaire were used as comparator instruments for the evaluation of criterion and construct validity, respectively. Internal consistency reliability was assessed using Cronbach's alpha.ResultsThe final XI/SXI-Thai were found to have good content validity. Both scales were able to distinguish between xerostomia and non-xerostomia groups. We observed moderate to strong correlation between the XI/SXI-Thai and other comparator instruments, reflecting good criterion and construct validity. Cronbach's alpha values were 0.875 and 0.847 for the XI-Thai and SXI-Thai, respectively.ConclusionsThe XI-Thai and SXI-Thai were found to be valid, reliable, and easily administrable instruments for xerostomia assessment in Thai middle-aged and older individuals in both clinical and research settings.