The reliability and validity of pain interference measures in persons with multiple sclerosis.

Valid measures of pain-related interference with functioning could serve as useful outcome measures in much needed clinical trials of pain treatments for persons with multiple sclerosis (MS). The purpose of this study was to examine the psychometric properties of two pain interference measures in persons with MS and chronic pain. Modified versions of the Interference scale of the Brief Pain Inventory (BPI) and the Disability scale of the Graded Chronic Pain Scale were administered via a mailed survey to 187 community-dwelling persons with MS. Data from the 125 participants who reported pain were analyzed. Although both measures demonstrated excellent internal consistency, in the current sample, evidence regarding the construct and concurrent validity was stronger for the modified versions of the BPI Interference scale. These results provide preliminary support for the reliability and validity of modified versions of the BPI Interference scale in persons with MS and chronic pain.