Direction dependent hysteresis in the Visual Analogue Scale for pain evaluation in humans

摘要

Visual Analogue Scale (VAS) is the most established method for estimating the magnitude of pain. However, VAS relies on subject's subjective sensation. Recently, quantitative measurement method for the magnitude of pain using painless electrical stimulation (PainVision~R PS-2100, Nipro Co., Osaka, Japan) was developed in Japan, we therefore tried to evaluate pain quantitatively. In this study, we evaluated the subject's level of pain with a weight loading test using VAS and Pain Vision~R, and examined the values obtained from both methods. As a result, when the magnitude of pain was changed, there was a significant difference in the VAS values even in between the equal magnitude of pain, but there was no significant deference in the values obtained from Pain Vision~R. There was direction dependent hysteresis in the VAS values and subjective sensation, on the other hand, Pain Vision~R might detect the subject's objective sensation.