Heat Pain Threshold Measurement Using Akabane's method and Problems Associated with it and Potential Improvements in Clinical Practice

Abstract

The basis of Akabane's method is the evaluation of latent periods (LPs) of heat pain in the fingertips skin where there are acupuncture channels. Each of these LPs is the period elapsing between the application of a heat stimulus and the caused heat pain. The evaluation allows identifying acupuncture channels lesions. Thereby, acupuncture treatment for many diseases may easily be prescribed. Unfortunately, the boundaries of reliability and the error of one measurement by this method have not yet been exactly determined. These circumstances do not allow the method to be improved. The purpose of this work was to overcome the above-mentioned problems. 47 healthy subjects were examined. LPs were determined 3 times with 20-minute interval. The patterns of changes in heat sensations during LP were also studied. Results: We defined by statistical investigation the LPs are valid in ranging from 6 to 55 seconds when the first measurement. The value of LP measurement error is increased during this period from ± 3 to ± 5.5 seconds in accordance with the formula of S-shaped curve. Re-measurement in 20 minutes at the same loci is not reliable. We confirmed the presence of the skin stable zones which differ in thermal pain sensitivity. We found wavelike changes of thermal sensitivity during heating with a half-cycle of 60-90 seconds when painful stimuli and 120-150 seconds when closely to pain. We have determined the ratio of LPs and the sensitivity states of the respective receptive zones are linear in the area of strong thermal sensations. This ratio may be named the generalized basic law of psychophysics since the Weber-Fechner law is its particular case. Conclusions: Akabane's method in its classic form is not significant because many LPs obtained by it are either very short or very long. However, using the LP errors and other regularities obtained by us it can be developed into significant. This will improve the examination of patients, specify and individualize their treatments, and will also allow the method to be used for scientific researches. In addition, the examination time will be reduced from 15-30 to 8-15 minutes.