Using electrical conductance as the evaluation parameter of pain in patients with low back pain treated by acupuncture-like TENS

Abstract

This study was to objectively evaluate the treatment effect of acupuncture-like transcutaneous electrical nerve stimulation (AL-TENS) on patients with low back pain. Fifty patients suffering from low back pain for at least three months were involved in the study from Chang Gung Memorial Hospital. The subjects were treated with TENS (100 Hz) on acupuncture points (BL23 and BL25). Two electrodes were placed on two right acupoints and two electrodes on the left. Pulse duration of electrical stimulation was fixed at 0.1 ms. The intensity of stimulation was adjusted at a tolerable level for each subject. Patients were treated for twenty minutes per visit, three times a week for two weeks. Visual analog scale (VAS) was used to rank the degree of pain before and two weeks after the treatment. A device, the design of which is based on the Ryodoraku theorem, was used to measure the electrical conductance of 12 meridians and 2 acupoints (BL23 and BL25) on both sides of the subjects. The effect of age difference on the pain score was also evaluated with the electrical conductance. The correlation between the VAS and the electrical conductance in the patients before and after treatment of AL-TENS was determined by linear regression analysis. The results showed that: (1) after the AL-TENS treatment in this study, the electrical conductances of either meridians or acupuncture points increased with the decrease of VAS of the patients; (2) the correlation was higher in the acupoints than that in the meridians; (3) the correlation was higher in the younger group than that in the older group; (4) the effect of AL-TENS on the change of VAS is more related to the change of electrical conductances of acupoints than that of meridians. These findings suggest that electrical conductance of meridian or acupoint can be used to evaluate the degree of pain more objectively, especially in the younger patients.