Efeitos imediatos de diferentes intensidades da estimulação transcutânea medular por corrente contínua em diferentes intensidades na dor crônica: estudo controlado randomizado

Abstract

Chronic pain features itself amidst the main concerns of the public health agenda, since its burden hinders social activities and happens to be a primary driver of absenteeism and reduced work productivity. Transcutaneous Direct Current Stimulation (tsDCS) has emerged as a promising method for managing chronic pain via non-invasive targeting of neurotransmitter systems and modulatory regions involved in pain perception. However, the existing literature still lacks clinical studies with rigorous methodology and adequately representative samples. Objective: This study aimed to assess the immediate effects of tsDCS on pain outcomes, as measured by the visual analog scale (VAS) and pressure pain threshold, in a cohort of 55 participants experiencing chronic pain (>3 months). Specifically, we compared the efficacy of tsDCS at an intensity of 2 mA (N=22) against sham stimulation at 0.5 mA (N=23). Material and methods: A controlled, randomized trial was conducted involving 55 participants equally allocated into two groups: real (2 mA) and sham (0.5 mA). Each participant underwent a 20-minute session of transcutaneous direct current stimulation. Pain outcomes were evaluated pre- and post-intervention using the Visual Analog Scale and pressure algometry. Statistical analyses included repeated measures ANOVA to assess the differences within and between groups, along with chi-square tests to evaluate responsiveness. Significance was established at p < 0.05. Results: Findings showed significant temporal effect for both VAS (F = 21.057; p < 0.001) and pressure algometry (F = 4.430; p = 0.04). However, no between-group differences were noted in the time*group factor for VAS (F = 0.539; p = 0.466) and pressure algometry (F = 0.07; p = 0.78). No significant between-group differences were observed for the responsiveness analysis. Conclusion: The results indicate that a single 20-minute session of 2 and 0.5 mA tsDCS improves pain scores for both intensities equally. However, there were no statistically significant between-group differences in pain perception or pressure pain threshold.