Detection of simulation among persons instructed to exaggerate symptoms of low back pain

A verbal pain measure was recently introduced that is accurate in differentiating patients with low back pain from persons who simulate pain. It consists of 103 pain words. Forty-five of these pain words accurately classified 219 out of 262 (83.6%) volunteers without pain who simulated back pain. In this study, 150 subjects with low back pain were administered the pain scale and instructed to exaggerate their pain sufficiently to convince a doctor of back pain that is severe enough to prevent them from working. Similar instructions were given to 267 persons without pain to determine the accuracy of the scale in detecting simulation, when some nidus of pain is present, and also to determine the influence of a pain history on scale accuracy. The pain measure detected 96 of 150 subjects with existing pain for an accuracy rate of 64.0%, and 218 of 267 subjects without pain for an accuracy rate of 81.7%. A selected cutoff score (-1.6) reduced classification error to less than 3% in the subject group with pain. The results underscore the impression that people who have pain to build on will be more difficult to detect when they simulate than people who engage in the process when they are pain free.