Effects of High Voltage Electro-auriculotherapy on Experimental Pain Threshold

Abstract

Summary Background and Purpose Approaches to pain management have improved over the years, but many of them are still invasive or have serious side-effects. Electro-acupuncture is accepted as a non-invasive and non-addictive method of pain management. Although much work in this area has been done to date, more studies need to be conducted to ascertain: ▪ The effect of high voltage electrical stimulation at auricular acupuncture points on experimental pain threshold measured at the wrist. ▪ The target specificity of auricular acupuncture points for its effects on experimental pain threshold. ▪ The changes in effect over time. Subjects Ninety healthy subjects participated in this study. The subjects were assigned randomly to one of three treatment groups. Group 1 (n = 30) received high voltage electrical stimulation to four real auricular points for wrist pain, group 2 (n = 30) received high voltage electrical stimulation to four sham auricular points, and group 3 (n = 30) received no high voltage electrical stimulation. Method A double-blind within-subject design was used in this study. A baseline cutaneous experimental pain threshold to rectangular electrical pulses was determined at the volar aspect of the left wrist. After localisation of auricular points using an electronic point finder, subjects in groups 1 and 2 received 10 minutes high voltage electrical stimulation on real and sham auricular points respectively, while group 3 received no stimulation. The experimental pain thresholds were again measured immediately after treatment, and at 5 and 10 minutes after treatment. Results Groups 1 and 2 had a statistically significant increase in experimental pain threshold at the third post-treatment measurement (10 minutes). There was no significant difference between groups 1 and 2 in pre- and post-treatment measurements. The changes in pain threshold were not significant in group 3. Conclusion These results suggest that the increase in experimental pain threshold following high voltage electrical stimulation of auricular points increases up to 10 minutes but may continue to increase beyond this time. The results also suggest that treatment of sham points was as effective as treatment of specific auricular points.