Pathway sensory evaluation system

A thermal contact-heat stimulator (PATHWAY sensory evaluation system, Medoc Ltd., Israel), with a thermode having a circular contact area of 572.5 mm² (27 mm in diameter), was employed in the present study to deliver innoxious and noxious stimuli. For each stimulation condition, the rates of temperature increase and decrease were 70°C/s and 40°C/s, respectively. The thermode was slightly repositioned after each stimulation condition to minimize nociceptor sensitization or habituation.

HPT test was performed on three sites on the right side by using the PATHWAY sensory evaluation system (Medoc Ltd., Israel). The three sites were the forearm (5 cm above the volar wrist transverse striation), rectus femoris (10 cm above the upper margin of the patella), and tibialis anterior muscle (one-half of the distance between the tibial tuberosity and lateral malleolus). Three marks were placed approximately 1 inch apart over each test muscle to ensure similar test point before and after inventions. A slow-heating probe (AST stimulator) was used at a baseline temperature of 36 °C, heating rate of 1 °C/s and cooling rate of 3 °C/s. HPT was determined as the temperature when subjects initially felt pain from the rising temperature and pressed a button to terminate the rise. The test was performed three times for each site with a time gap of 5 s, and the average value was obtained.