The effects of different TENS frequencies applied to LU7 acupoint on cold-induced pain test

Abstract

Introduction: Pain represents a frequent phenomenon among the general population with great socioeconomic impact. TENS is one of the most common forms of electroanalgesia. However, totally effective stimulation parameters remain uncertain. Thus, this study aims to assess the effects of 4 Hz, 10 Hz and 100 Hz TENS applied to the LU7 (Lieque) acupoint on cold-induced pain in young healthy subjects. Methods: 100 volunteers, divided into five groups (three TENS groups, one electrode group and one placebo group), completed six experimental cycles. Each cycle comprised three phases: pretreatment, treatment and posttreatment. In each cycle, pain was induced by immersion of the hand into ice water and the pain threshold latency was measured. For the analysis of results, we used the one-way ANOVA test, followed by the Student-Newman-Keuls post hoc test. The level of significance was p < 0.05. Results: The 4 Hz TENS group the pain showed elevation of the pain threshold during the treatment phase, when compared to pretreatment (p < 0.05). This elevation was maintained in the post-treatment phase. The other groups showed no changes in the pain threshold. Conclusion: 4 Hz TENS applied with 1x1 cm electrodes to LU7 acupoint increases hypothermia-induced pain threshold latency in young healthy subjects.