Abstract
Purpose: Conditioned pain modulation （CPM）, temporal summation of pain （TSP） and offset analgesia （OA） are considered to represent the endogenous pain modulation and could be the risk factor of acute and chronic postsurgical pain. The aim was to develop the measurement device for the evaluation of endogenous pain modulation with cold, heat and pressure stimulation.
Materials and methods: The cold and heat stimulating device with Peltier element was controlled by PC. The development environment was Microsoft Visual Studio 2017, and the development language was C#. The setting temperature and measured temperature for CPM, TSP, and OA measurements were displayed in separate windows. Created program was possible to change condition of stimulation such as temperature, and could control temperature between −10 and 50 degrees Celsius. The continuous electronic visual analogue scale （eVAS） for pain and subjective sensation for cold and heat stimulation were also displayed. The results of CPM effect, TSP ratio and OA score in healthy adults were 19.4 （31.8）％, 1.1 （1.1） and 25.5 （40.5）, respectively （median （interquartile range））.
Discussion: The developed device was a safe and useful measuring instrument for the evaluation of CPM, TSP, and OA which would reflect endogenous pain modulation, in a short time without burdening the subject.
Conclusion: The device for the evaluation of endogenous pain modulation with cold, heat and pressure stimulation was developed.
