Impact of Bifrontal Home-Based Transcranial Direct Current Stimulation in Pain Catastrophizing and Disability due to Pain in Fibromyalgia: A Randomized, Double-Blind Sham-Controlled Study

This randomized, double-blind trial tested the hypothesis that 20 sessions of home-based anodal(a)-transcranial direct current stimulation (tDCS) (2mA for 20 minutes) bifrontal, with anodal on the left dorsolateral prefrontal cortex (l-DLPFC) would be better than sham-(s)-tDCS to reduce scores on Pain Catastrophizing Scale and disability-related to pain assessed by the Profile of Chronic Pain: Screen (primary outcomes). Secondary outcomes were depressive symptoms, sleep quality, heat pain threshold , heat pain tolerance , and serum brain-derived-neurotrophic-factor (BDNF). Forty-eight women with fibromyalgia, 30 to 65 years-old were randomized into 2:1 groups [a-tDCS (n = 32) or s-tDCS (n = 16)]. Post hoc analysis revealed that a-tDCS reduced the Pain Catastrophizing Scale total scores by 51.38% compared to 26.96% in s-tDCS, and a-tDCS reduced Profile of Chronic Pain: Screen total scores by 31.43% compared to 19.15% in s-tDCS. The a-tDCS improved depressive symptoms, sleep quality and increased the heat pain tolerance. The delta-value in the serum BDNF (mean post treatment end minus pretreatment) was conversely correlated with the a-tDCS effect in pain catastrophizing. In contrast, the a-tDCS impact on reducing the disability-related to pain at the treatment end was positively associated with a reduction in the serum BDNF and improvement of depressive symptoms, sleep quality and pain catastrophizing symptoms. PERSPECTIVE: Home-based bifrontal tDCS with a-tDCS on the l-DLPFC are associated with a moderate effect size (ES) in the following outcomes: 1) Decreased rumination and magnification of pain catastrophizing. 2) Improved the disability for daily activities due to fibromyalgia symptoms. Overall, these findings support the feasibility of self-applied home-based tDCS on DLPFC to improve fibromyalgia symptoms.