著者
嶋津 秀昭 瀬野 晋一郎 加藤 幸子 小林 博子 秋元 恵実
出版者
公益社団法人 日本生体医工学会
雑誌
生体医工学 (ISSN:1347443X)
巻号頁・発行日
vol.43, no.1, pp.117-123, 2005 (Released:2007-01-19)
参考文献数
14
被引用文献数
4

We have developed a method and a system to quantitatively evaluate human pain without relying on subjective criteria. The concept of pain quantification is to compare the magnitude of the subject's pain to the magnitude of a painless electric stimulus that is comparable to actual pain. We quantified degree of pain as the pain ratio, based on the ratio between pain equivalent current and minimum perceived current. In the system developed as the objective of this study, a gradually increasing pulsed current (frequency was 50 Hz, and the pulse width was 0.3 ms) was applied to the subject's medial forearms, and the subjects compared the magnitude of this sensation to electrical stimulation produced by an electrical current. Using test equipment, we conducted basic evaluations of measurement principles. We induced two types of experimental pain, by applying weight load to the upper arm and the lower leg, and by pinching the skin using clips. We examined whether changes in the degree of sensation with respect to electrical stimulation used in this method could be accurately observed, and whether or not it was possible to accurately and with high reproducibility measure minimum perceived current and pain equivalent current. As a result, we were able to make a clear comparison between pain and the degree of stimulation by electrical current, which was a sensation differing from pain. Although there were individual differences in the measured values, the reproducibility of the pain equivalent current as measured was favorable, and the measured values for pain ratio were also reproducible. We confirmed in the present study that the degree of experimental pain can be expressed as quantitative numerical values using an index defined as pain ratio.