Sensory decision theory and visual analogue scale indices predict status of chronic pain patients six months later.

Thirty-nine outpatients suffering from chronic pain were studied in a multidisciplinary program. Pain intensity on a visual analogue pain scale (VAPS), sensory decision indices of thermal discriminability, P(A), and pain report criterion, B, age and sex obtained before treatment, were used to predict the patients' status, determined by a follow-up questionnaire 6 mo later. The results showed that patients who were high on the VAPS at intake had shorter pain relief and decreased physical activities on follow-up. Patients with better thermal discriminability had greater pain relief, while those with low pain report criterion, that is, less stoical, demonstrated improved physical activity, and more social and hobby activities. Patients who were less stoical to thermal stimuli (lower pain criterion) took fewer centrally active drugs after treatment. Younger patients showed greater improvement at follow-up. The data indicate that the VAPS, thermal discriminability, and pain report criterion all predict the duration of pain relief after treatment. Nevertheless, each of these variables had its individual character. The VAPS was most efficient in predicting physical activities, thermal discriminability related best to pain relief, and pain report criterion to social and hobby activities as well as drug intake.