Title:
Validity and reliability of an adapted Thai version of Scoliosis Research Society-22 questionnaire for adolescent idiopathic scoliosis.

Abstract:
Cross-sectional observational study to investigate psychometric properties of an adapted Thai version of the refined Scoliosis Research Society-22 (SRS-22) questionnaire.
To evaluate the reliability and validity of the adapted Thai version of the refined SRS-22 questionnaire.
The SRS-22 questionnaire is a valid instrument for assessing the health-related quality of life for patients with adolescent idiopathic scoliosis. Recently, the questionnaire has been translated and validated in many languages for non-English-speaking countries.
Translation/retranslation of the English version of the SRS-22 was conducted, and the cross-cultural adaptation process was performed. The Thai version SRS-22 and previously validated Thai version Short-Form survey version 2.0 (SF-36V2) questionnaires were administered to 77 patients with adolescent idiopathic scoliosis who had surgical treatment. Fifty-eight patients (52 adolescent girls) had filled out the first set of questionnaires. Thirty patients of the first-time responders completed the second set of questionnaires. The mean age at the time of operation was 14.6 years and the mean age at the time of the final follow-up was 18.7 years. The mean preoperative scoliosis curve magnitude was 55.4° (range, 30°-95°) and postoperative curve magnitude was 20.1° (range, 0°-60°). Internal consistency was determined with Cronbach α coefficient. Intraclass correlation coefficient was used for test-retest reliability. Concurrent validity was evaluated by comparing SRS-22 domains with relevant domains in the SF-36V2 questionnaire, using the Pearson correlation coefficient.
The mean overall Cronbach α coefficient of the adapted Thai version SRS-22 was 0.76. The 2 of corresponding domains (mental health = 0.80 and self-image = 0.83) had satisfactory internal consistency and the remaining domains (pain = 0.78; function/activity = 0.74; and satisfaction = 0.76) were good. The intraclass correlation coefficient for 5 domains was ranged from 0.79 to 0.90, which demonstrated the satisfactory test/retest reproducibility. The concurrent validity, determined by the Pearson correlation coefficient between SRS-22 and SF-36V2 domains, had a good correlation for 15 relevant comparisons (r = 0.50-0.75).
The adapted Thai version of the SRS-22 questionnaire had validity and reliability, which can be used to assess the outcome of treatment among Thai-speaking patients with adolescent idiopathic scoliosis.