Neck Disability Index

Neck Disability Index

Items: 10

Scoring: Each item scored 0 to 5 (lower scores indicating more desirable health states).

Score Range: Total score is out of 50 points (Higher scores indicate greater disability)

Internal Consistency: .80 (n=52) (Vernon et al 1991), .87 (Stratford et al 1999)

Test-Retest Reliability: .89 (n=17)(Vernon et al 1991), .94 (Stratford et al 1999)

Validity: NDI and McGill Pain Questionnaire correlation or .70 (for total score) and .69 (for numbers of words) where n=30 (Vernon et al 1991). Correlation between NDI and SF-36 Physical and Mental component scores (n=146) were .53 and .47 respectively (Riddle et al 1998). Analysis showed that the NDI was able to discriminate between patients of different health status(p<.001). These comparisons include when comparing patients whose work status was altered and will demonstrate greater disability than patients whose work status was not altered and patients who were involved in litigation at the time of the initial assessment will demonstrate greater disability than patients who were not involved with litigation.

Assessing change over time: Correlation between NDI and VAS for pain was .60 (Vernon et al 1991)

SEM test-retest=2 NDI points (upper 1-sided 95%CI=2.7 NDI points) (Stratford et al 1999)
MDC90=4.7points (Sensitivity=.78 with 95%CI .62 to .94; Specificity=.80 with 95%CI .64 to.96) (Stratford et al 1999)

Area under ROC curve=.90(Stratford et al 1999)

Word doc of form attached below


1. Riddle, D.L., Stratford, P.W.Use of generic versus region specific functional status measures on patients with cervical spine disorders: A comparison study. Physical Therapy. 1998. 78:951-963.

2. Stratford, P.W., Riddle, D.L., Binkley, J.M., Spadoni, G., Westaway, M.D., Padfield, B. Using the Neck Disability Index to Make Decisions Concerning Individual Patients. Physiotherapy Canada. 1999. 107-112.

3. Vernon, H., Mior, S. The neck disability index: A study of reliability and validity. Journal of Manipulative Phisiol Ther. 1991. 14: 409-15.

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