Development and Validation of Taiwanese Version of the Neck Disability Index

STUDY DESIGN.Cross-cultural adaptation and cross-sectional psychometric testing in a convenience sample of patients with neck pain. OBJECTIVE.To translate and cross-culturally adapt the Neck Disability Index (NDI) into a Taiwanese version and to assess the psychometric properties. SUMMARY OF BACKGROUND DATA.The Taiwanese NDI has not been developed or validated. METHODS.The NDI was first translated and culturally adapted to the Taiwanese version. The test-retest reliability within 1 week was examined (n = 32). The factor structure was assessed by confirmatory factor analysis (n = 137). The construct validity was assessed by examining the relationship between the NDI and other well-known measures (n = 137). RESULTS.The Taiwanese version was successfully translated and cross-culturally adapted. The internal consistency was excellent, with Cronbachʼs α = 0.89. High test-retest reliability was demonstrated with intraclass correlation coefficients of 0.87. The minimal detectable change was 8.74. The two-factor model (Pain and Function factors) was better than the one-factor model, with higher factor loadings and better goodness of fit statistics. The convergent validity was supported by moderate correlation of the Pain factor with the Visual Analogue Scale (|rho| = 0.45), and high correlation of the Function factor with the Physical Component Summary of the SF-36 (|rho| = 0.60). CONCLUSION.The Taiwanese NDI is a reliable and valid disease-specific measure for assessment of pain and functional status in patients with neck pain.Level of Evidence3