RESEARCH REPORT PLATFORM PRESENTATION

TRANSLATING NECK PAIN AND DISABILITY QUESTIONNAIRES INTO THE KOREAN LANGUAGE: CROSS-CULTURAL ADAPTATION AND PSYCHOMETRIC TESTING. Lee H¹, Nicholson L², Adams R², Maher C², Halaki M³, Bae S⁴; ¹Dept of Physical Therapy, College of Medical Life Science, Silla University, Busan, Korea. ²School of Physiotherapy, Faculty of Health Sciences, University of Sydney, Sydney, Australia. ³School of Exercise and Sport Science, Faculty of Health Science, University of Sydney, Sydney, Australia. ⁴Dept of Physical Therapy, College of Rehabilitation Science, Daegu University, Daegu, Korea

PURPOSE: To translate three neck and spinal pain disability questionnaires – the NDI, NPDS, and FRI – into the Korean language, and evaluate reliability, face validity and item response patterns to achieve a good cross-cultural adaptation. RELEVANCE: Although measuring health status is important for research and clinical practice, few validated neck pain and disability scales exist. Further, non-English speakers are often excluded from clinical trials and epidemiological studies due to the lack of valid and reliable cross cultural measurements. There are no Korean language neck pain and disability measures. Direct translations may fail to achieve questions comparable to the meaning of the original English, so it is important to consider conceptual matters and cultural relevance. PARTICIPANTS: Forty (23 males, 17 females) subjects, aged from 15 to 64 years old, participated to examine test-retest reliability. One hundred and eighty (76 males, 104 females) subjects with a primary diagnosis of non-specific neck pain and 81 healthy volunteers were recruited to examine internal consistency, discriminative validity and longitudinal construct validity. METHODS: Versions of each questionnaire in idiomatic modern Korean were developed with a process involving initial independent translation, synthesis of the translations, independent back translation and review by an expert committee to achieve equivalence with the original English. Psychometric testing of the questionnaires was undertaken to examine test-retest reliability, internal consistency, discriminative validity and longitudinal construct validity. The questionnaires were administered twice to the clinical subjects; on their first treatment (baseline) and the last treatment day (post treatment). A 7-point global perceived effect scale was also completed at the last treatment and served as the external criterion of clinically important change. The healthy group completed the questionnaires once only. Prior to testing, ethical approval was obtained from the University of Sydney, and each subject gave informed consent. ANALYSIS: To assess reliability, the intraclass correlation coefficient [ICC(2,1)] was calculated. Internal consistency was evaluated by Cronbach’s alpha. Discriminative validity was examined with independent-groups t -tests. Internal responsiveness was tested by calculating the effect size and standardized response mean for each questionnaire, and external responsiveness was measured using Pearson’s r and ROC analysis. RESULTS: Test-retest reliability of the translated versions of the three disability questionnaires was excellent [ICC(2,1) = 0.86-0.90]. High internal consistency was found in the three disability questionnaires (Cronbach’s alpha was 0.88 for the FRI, 0.96 for the NPDS and 0.82 for the SFMPQ). The VAS subscale of the SFMPQ was found to be the most responsive subscales (ES=1.44, SRM=1.37). The VAS was also the most responsive pain and disability index in internal responsiveness analysis, although disability indices showed marginally better responsiveness when compared with external standards. CONCLUSIONS: We conclude that the questionnaires were successfully translated and exhibit acceptable measurement properties, and as such are suitable for use in clinical and research applications. IMPLICATIONS: The results of the current study may suggest that Korean versions of four common neck pain and disability questionnaires are suitable for use in clinical and research applications. KEYWORDS: Responsiveness, Neck disability questionnaires, Short Form McGill Pain Questionnaire. FUNDING ACKNOWLEDGEMENTS: None of authors have any financial support for the current study that may lead to a conflict of interest. CONTACT: hjlee@silla.ac.kr

ETHICS COMMITTEE: University of Sydney