Immediate Effects of distinct intensities of Transcutaneous Spinal Direct Current Stimulation on Chronic Pain: A Randomized Controlled Trial

This study aimed to assess the immediate effects of transcutaneous spinal direct current stimulation (tsDCS) on pain outcomes, measured by the visual analog scale (VAS) and pressure pain thresholds in a cohort of 55 participants experiencing chronic pain. A controlled, randomized trial with 55 participants allocated into 2 groups: 2 mA and 0.5 mA of tsDCS for 20 minutes. Anodal stimulation was applied on the 12th thoracic vertebra, and cathodal stimulation on the 7th cervical vertebra. Pain outcomes were assessed before and post-intervention using the VAS and pressure algometry. Between and within-group differences, along with chi-square tests were used to determine the differences and responsiveness. Significance was established at p < 0.05. Findings showed significant temporal effect for both VAS (p < 0.001) and pressure algometry (p = 0.04). However, no between-group differences were noted in the time*group factor for VAS (p = 0.466) and pressure algometry (p = 0.78). No significant between-group differences were observed for the responsiveness analysis. 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.