Reliability and validity of the pain on movement questionnaire (POM) in chronic neck pain

Abstract

Objective: This analysis aimed to determine reliability, validity, and responsiveness of the pain on movement (POM) questionnaire, an instrument developed to determine pain intensity induced by head movement. Design: Data from nine randomized controlled trials for the treatment of chronic nonspecific neck pain were reanalyzed to determine reliability and validity of the POM questionnaire. Methods: POM was assessed as ratings of pain intensity induced by head movement in six different directions. The instrument's structure was assessed using a factor analysis. Reliability (internal consistency) was determined using Cronbach's alpha, and validity (convergent validity) was determined by correlating the POM with pain at rest on a visual analog scale (VAS), the neck disability index (NDI), quality of life (short-form 36 health survey questionnaire [SF-36]) and range of motion. Responsiveness was indicated by sensitivity to changes over time in a subsample of 49 patients. Results: Overall, 482 patients (mean age 50.3±12.4 years, 72.3% female) were included in the analysis, and 458 of them provided complete data set for the POM. Average POM was 43.9±20.8mm on the VAS. The POM showed very good reliability as indicated by high internal consistency and moderate validity as indicated by significant correlations with the pain at rest, the NDI, and the SF-36. No correlations were found for POM with range of motion. The POM further proved to be responsive as it was sensitive to changes over time, and those changes were correlated to changes in pain intensity and NDI. Conclusions: The POM seems to be a reliable and valid instrument to assess POM in patients with chronic nonspecific neck pain.