Reliability and responsiveness of three different pain assessments

The visual analogue scale (VAS) and ordered categorical scales, i.e. numeri c rating scales (NRS), are commonly used in the assessment of pain. However , these scales are bounded by fixed endpoints and thus the range of measure ment is limited. The disparity in repeated assessments of perceived pain in tensity with the VAS, NRS, and electrical stimulation applied as a matching stimulus was studied in 69 patients (48 women and 21 men, 19-72 years) wit h chronic nociceptive or neurogenic pain. Responsiveness with transcutaneou s electrical nerve stimulation (TENS) using the same measurement procedures was evaluated in the same patients. Comparison of results from the three p ain assessments showed that the painmatcher is at least as reliable and res ponsive as VAS and NRS. None of the three measurements showed evidence for systematic disagreement and had only significant random individual disagree ment. They also showed evidence for responsiveness.