Development of the Neck Pain and Disability Scale. Item analysis, face, and criterion-related validity

Abstract

Study design: The development and testing of a new comprehensive measure of neck pain and disability, the Neck Pain and Disability Scale.

Objectives: To provide an initial evaluation of the Neck Pain and Disability Scale's reliability and validity.

Summary of background data: Although several measures exist for generalized pain and disability, none is specific for neck pain. More specific measurements should improve assessment of treatments and clinical research aimed at cervical pain syndromes.

Methods: The Neck Pain and Disability Scale was designed using the Million Visual Analogue Scale as a template and consists of 20 items that assess neck pain. In this study, 100 patients with neck pain, 52 patients with lower back and leg pain, and 27 pain-free volunteers were rated by the Neck Pain and Disability Scale. In addition, a subset of the 47 patients with neck pain were rated by several other established psychometric instruments.

Results: An item analysis showed a high degree of internal consistency among the 20 items on the Neck Pain and Disability Scale (r = 0.93), and face validity was established by comparing patients who had neck pain as well as lower back and leg pain with a pain-free group. The Neck Pain and Disability Scale scores correlated with the Oswestry Disability Questionnaire, the Pain Disability Index, and psychological measures of depression and neuroticism.

Conclusions: The results suggest a highly reliable instrument for evaluating neck pain with at least four underlying dimensions. Further work to address the predictive validity of this new tool are under way.