The effectiveness of home-based transcranial direct current stimulation on chronic pain: A systematic review and meta-analysis

Objective As highlighted by the COVID-19 pandemic, identifying strategies for home-based patient management is crucial. As pain is highly prevalent and imposes significant burdens, interest in its remote management is steadily increasing. Transcranial Direct Current Stimulation (tDCS) seems promising in this context. Methods This systematic review and meta-analysis aimed to determine the effectiveness of home-based tDCS in pain management (PROSPERO, CRD42023452899). The extracted data included clinical conditions, interventions, comparators, outcome measures, adverse effects, and risk of bias; the Grading of Recommendations Assessment, Development and Evaluation (GRADE) assessment was carried out. Results 12 records (9 randomized controlled trials [RCTs], 446 participants, 266 undergoing tDCS) were included in the systematic review. The meta-analysis showed that home-based tDCS might produce large and clinically relevant improvement in chronic pain intensity at the end of the intervention (standard mean difference [SMD] -0.95, 95% CI -1.34 to -0.56; p < 0.01; 404 participants, low certainty), as well as small clinically unimportant improvement at short-term follow-up (SMD -0.50, 95% CI -0.82 to -0.19; p < 0.01; 160 participants, moderate certainty). A subgroup analysis showed that it might clinically improve the chronic pain related to fibromyalgia and knee osteoarthritis. Moreover, home-based tDCS seems to modulate pressure pain threshold, heat pain threshold, and heat and cold tolerance at the end of the intervention. Notably, tDCS appeared to be generally safe, well-accepted and easily applied at home. Conclusions Low to moderate certainty evidence suggests that home-based self-administered tDCS is a safe and effective tool for managing various types of chronic pain. Further well-designed, large-scale RCTs are warranted.