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

OBJECTIVE: To 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. METHODS: The 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. RESULTS: The 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. CONCLUSIONS: The 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.

The validity and reliability of the Indonesian version of the Summated Xerostomia Inventory.

OBJECTIVE: To validate and determine the reliability of the Indonesian version of the Summated Xerostomia Inventory (SXI-ID) questionnaire. BACKGROUND: Xerostomia is a common problem in older people, and the SXI is increasingly being used to measure it. MATERIALS AND METHODS: The SXI questionnaire was cross-culturally adapted to create an Indonesian version (SXI-ID), which was assessed for validity and reliability in a cross-sectional study of older adults living in nursing homes in Jakarta, Indonesia. Each participant signed an informed consent and was interviewed with the SXI-ID. A subset of participants was interviewed again after two weeks. A standard question was used to check criterion-related validity, by plotting the mean SXI-ID scale scores against the ordinal response categories of the standard question. The reliability check included Cronbach's alpha, total and inter-item correlation, and intraclass correlation for internal consistency, along with test-retest reliability. RESULTS: A total of 110 older adults participated. Cronbach's alpha value for the SXI-ID was .85, and the intraclass correlation coefficient value for test and retest in 15 participants was .9. The SXI-ID total score showed a strong positive correlation (.87) with the global question. There was a consistent ascending gradient in mean SXI-ID scores across the ordinal response categories of the global item. CONCLUSION: The SXI-ID is psychometrically valid and reliable for measuring xerostomia in the Indonesian population.

Validating the Xerostomia Inventory in a radiation-induced xerostomia population in German language.

OBJECTIVES: Though xerostomia is a frequent oral symptom, there is no validated disease-specific questionnaire in German. The purpose of this study was to translate and validate versions of the Xerostomia Inventory and the Summated Xerostomia Inventory in a German-speaking population. PARTICIPANTS AND METHODS: Thirty-nine patients including 18 patients suffering from radiation-induced xerostomia enrolled in this study. Both questionnaires were translated into German language according to international accepted guidelines. For validation, we evaluated reliability, validity, and responsiveness using the COSMIN manual for cross-cultural adaptation. RESULTS: Cronbach's α was 0.92 for XI and 0.91 for SXI, showing both high internal consistency. Patients suffering from xerostomia showed significantly higher average scores demonstrating its discriminant validity. Confirmatory factor analysis showed excellent "goodness-of-fit" values for SXI and good to moderate values for XI, confirming the assumed factor structures. The Xerostomia Inventory and its summated version both showed excellent test-retest reliability in the non-xerostomia group (ICC = 0.85 and 0.84). CONCLUSIONS: The XI and SXI in their cross-cultural adapted versions are the first validated self-report assessments for xerostomia in German language. They are characterized by practical design and can be easily interpreted by the treating physician.