The reliability and validity of pain interference measures in persons with spinal cord injury.

UNLABELLED: The current study compared the psychometric properties of 2 commonly used measures of pain-related interference, the Graded Chronic Pain (GCP) Disability scale and 3 modified versions of the Brief Pain Inventory (BPI) Interference scale. Participants were 127 persons with spinal cord injury (SCI) who reported pain on a survey. The results suggest that the GCP Disability scale and 3 versions of the BPI Interference scale are reliable and valid measures of pain-related interference in persons with SCI and pain. All 4 measures evidenced excellent internal consistency. The composite scores and individual items of the GCP Disability scale and each version of the BPI Interference scale were significantly related to average pain intensity during the past week and a global measure of psychological functioning. Finally, as pain intensity ratings increased (from mild to moderate to severe), so did the composite and item-level ratings of interference for each version of the BPI Interference scale and GCP Disability scale. Strengths and weaknesses of each measure for use with persons with disability and pain are discussed. PERSPECTIVE: The GCP Disability scale and 3 versions of the BPI Interference scale (modified for use in persons with disabilities) appear to be reliable and valid measures of pain-related interference in persons with SCI. Future research should examine their psychometric properties in other disability populations.