Cross-Cultural Adaptation and Validation of the Korean Version of the Neck Disability Index

Purpose: To translate and culturally adapt a Korean version of the Neck Disability Index (NDI), as well as to validate its use in Korean patient. Materials and Methods: The NDI was linguistically translated into Korean and the prefinal version was assessed and modified by a pilot study. The Korean version was tested on 60 patients with degenerative cervical spine disease to verify the reliability and validity. The test-retest reliability, internal consistency, concurrent validity, and construct validity were examined by a comparison with the VAS and SF-36. Results: The intraclass correlation coefficient of test-retest reliability was 0.927. The reliability estimated by the internal consistency reached a Cronbach's alpha of 0.82. The correlation of the NDI with VAS was r=0.489 (p=0.002) and correlation between NDI and SF-36 was r=-0.44 (p＜0.01). The physical health component score of SF-36 showed a high correlation with the NDI as well as a high correlation between VAS and mental health component scores of SF-36. Conclusion: The Korean version of the NDI is a reliable and valid instrument for measuring the disability in Korean patient with cervical problems and can be useful in future clinical studies in Korea.