Study Design. This study's design was a cross-cultural validation of the Neck Disability Index (NDI) and Neck Pain and Disability Scale (NPDS).
Objective. To translate and validate Chinese versions of the NDI and the NPDS.
Summary of Background Data. The widely used NDI and NPDS scales have not been translated and validated for Chinese-speaking patients with neck pain.
Methods. The translation and cultural adaptation of the original questionnaires were carried out in accordance with the published guidelines. A total of 125 patients with neck pain participated in the study. Patients were asked to complete a questionnaire booklet including the NDI, the NPDS, the SF-36, and a visual analog scale (VAS) of pain. To determine the test-retest reliability, 45 patients were asked to complete the questionnaire booklet a second time within 48 hours of the first completion.
Results. The Cronbach α coefficient for the NDI was 0.89, and those for the 3 subscales of the NPDS were found to be satisfactory (0.91, 0.88, and 0.82, respectively). The NDI and the NPDS subscales showed excellent test-retest reliability (the intraclass correlation coefficient ranged from 0.86 to 0.95; P < 0.01). The correlation between the NDI and the NPDS subscales and functional scales of the SF-36 showed desirable results, indicating a good convergent validity (Pearson correlation coefficients ranged from −0.19 to −0.76). The correlation between the NDI and the VAS was 0.75, and that between the NPDS subscales and the VAS ranged from 0.62 to 0.76 (P < 0.01).
Conclusion. The Chinese versions of the NDI and the NPDS are reliable and valid instruments to measure functional status in Chinese-speaking patients with neck pain in China. They are simple and easy to use, and can now be applied in clinical settings and future outcome studies in China and other Chinese-speaking communities.
This study demonstrated adequate translation, cultural adaptation, and validity of Chinese versions of the Neck Disability Index and the Neck Pain and Disability Scale. Chinese versions of the questionnaires showed acceptable test-retest reliability, internal consistency, and good convergent validity. The results of the study suggest that the 2 scales are suitable for use in clinical and research applications.
From the From Pain Treatment Centre of Department of Rehabilitation Medicine, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong Province, China.
Acknowledgment date: April 22, 2009. Revision date: September 12, 2009. Acceptance date: September 12, 2009.
The manuscript submitted does not contain information about medical device(s)/drug(s).
No funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.
Address correspondence and reprint requests to Chao Ma, MD, PhD, Department of Rehabilitation Medicine, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 510120, 107 Yanjiang West Rd, Guangzhou, Guangdong Province, China; E-mail: firstname.lastname@example.org