Abstract
The relative value of nine spinal and thoracic mobility measurements was investigated in 73 male patients with ankylosing spondylitis (AS). The value of a test was obtained by the relative ranks of validity, reliability and sensitivity to change. Validity was determined as age-adjusted correlation of the test result with AS-specific radiological changes in the lumbar spine. Reliability was determined as inter-observer error. Sensitivity to change was determined as change in test result during an intensive rehabilitation course.
The five most valuable tests were rotation of the thoracolumbar spine (TR), finger-to-floor distance (FFD), the Schober test, thoracolumbar flexion and occiput-to-wall distance. Of these, FFD had high reliability and sensitivity ranks, but poor correlation with AS-specific spinal changes. TR had high validity and sensitivity ranks, and improvement of the measurement technology would probably result in a superior test for the follow-up of AS. Chest expansion and vital capacity had low ranks in all comparisons.