Outcome measures of functionality, social interaction, and pain in patients with cervical spondylotic myelopathy: A validation study for the iranian version of the copenhagen neck functional disability scale

Abstract

Purpose: To translate and validate the Iranian version of the Copenhagen Neck Functional Disability Scale (CNFDS). Overview of Literature: Instruments measuring patient-reported outcomes should satisfy certain psychometric properties. Methods: Ninety-three cases of cervical spondylotic myelopathy were entered into the study and completed the CNFDS pre and postoperatively at the 6 month follow-up. The modified Japanese Orthopedic Association Score was also completed. The internal consistency, test-retest, convergent validity, construct validity (item scale correlation), and responsiveness to change were assessed. Results: Mean age of the patients was 54.3 years (standard deviation, 8.9). The Cronbach α coefficient was satisfactory (α=0.84). Test-retest reliability as assessed by the intraclass correlation coefficient analysis was 0.95 (95% confidence interval, 0.92-0.98). The modified Japanese Orthopedic Association score correlated strongly with the CNFDS score, lending support to its good convergent validity (r =-0.80; p <0.001). Additionally, the correlation of each item with its hypothesized domain on the CNFDS was acceptable, suggesting that the items had a substantial relationship with their own domains. These results also indicate that the instrument was responsive to change (p <0.0001). Conclusions: The findings suggest that the Iranian version of the CNFDS is a valid measure to assess functionality, social interaction, and pain among patients with cervical spondylotic myelopathy. 2015 by Korean Society of Spine Surgery.