Reliability of a continuous pain score meter: real time pain measurement

We present a newly developed continuous pain score meter (CPSM). The CPSM is based on the principles of the visual analog score (VAS), and electronically measures pain score in a continuous, instead of a single, manner. In this study, we determine the test-retest reliability of this meter. Thirty-two healthy volunteers received a reproducible pain stimulus on the right thumbnail and forearm. After a 1-minute interval the procedure was repeated. During the stimulus, pain was continuously measured with the CPSM, providing values of peak continuous pain score (CPS) and area under the CPS curve (AUC CPS). The intra-class correlation coefficient (ICC) and the 95% limits of agreement were used to assess the agreement between measurements. ICC of peak CPS (0.89 and 0.83) and AUC CPS (0.79 and 0.86) for nail and arm showed a good reproducibility. This study has successfully established the test-retest reliability of the CPSM. The real-time continuous pain measurement may provide more detailed information on a subjects' pain perception compared to a single VAS, in particular during an interval of pain stimuli.