To update a systematic review of the efficacy and safety of transcranial direct current stimulation (tDCS) for analgesia, for antidepressant effects, and to reduce the impact of fibromyalgia (FM), looking for optimal areas of stimulation. We searched five databases to identify randomized controlled trials comparing active and sham tDCS for FM. The primary outcome was pain intensity, and secondary outcome measures included FM Impact Questionnaire (FIQ) and depression score. Meta-analysis was conducted using standardized mean difference (SMD). Subgroup analysis was performed to determine the effects of different regional stimulation, over the primary motor cortex (M1), dorsolateral prefrontal cortex (DLPFC), opercular-insular cortex (OIC), and occipital nerve (ON) regions. We analyzed the minimal clinically important difference (MCID) by the value of the mean difference (MD) for an 11-point scale for pain, the Beck Depressive Inventory-II (BDI-II), and the Fibromyalgia Impact Questionnaire (FIQ) score. We described the certainty of the evidence (COE) using the tool Twenty studies were included in the analysis. Active tDCS had a positive effect on pain (SMD= -1.04; 95 % CI -1.38 to -0.69), depression (SMD= -0.46; 95 % CI -0.64 to -0.29), FIQ (SMD= -0.73; 95 % CI -1.09 to –0.36), COE is moderate. Only group M1 (SD=-1.57) and DLPFC (SD=-1.44) could achieve MCID for analgesia; For BDI-II, only group DLPFC (SD=-5.36) could achieve an MCID change. Adverse events were mild. tDCS is a safe intervention that relieves pain intensity, reduces depression, and reduces the impact of FM on life. Achieving an MCID is related to the stimulation site and the target symptom.

中文翻译：

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经颅直流电刺激治疗纤维肌痛的疗效和安全性：系统评价和荟萃分析

更新对经颅直流电刺激 (tDCS) 镇痛、抗抑郁作用和减少纤维肌痛 (FM) 影响的有效性和安全性的系统评价，寻找最佳刺激区域。我们检索了五个数据库来确定比较主动和假 tDCS 治疗 FM 的随机对照试验。主要结果是疼痛强度，次要结果指标包括 FM 影响问卷 (FIQ) 和抑郁评分。使用标准化均差（SMD）进行荟萃分析。进行亚组分析以确定不同区域刺激对初级运动皮层（M1）、背外侧前额叶皮层（DLPFC）、盖岛皮层（OIC）和枕神经（ON）区域的影响。我们通过疼痛 11 点量表的平均差 (MD) 值、贝克抑郁量表 II (BDI-II) 和纤维肌痛影响问卷 (FIQ) 评分来分析最小临床重要差 (MCID) 。我们使用该工具描述了证据的确定性 (COE) 分析中纳入了 20 项研究。主动 tDCS 对疼痛（SMD= -1.04；95 % CI -1.38 至 -0.69）、抑郁（SMD= -0.46；95 % CI -0.64 至 -0.29）、FIQ（SMD= -0.73；95 %）有积极作用CI -1.09 至 –0.36)，COE 中等。仅M1组（SD=-1.57）和DLPFC组（SD=-1.44）能够达到镇痛MCID；对于BDI-II，只有DLPFC组(SD=-5.36)可以实现MCID改变。不良事件轻微。经颅直流电刺激 (tDCS) 是一种安全的干预措施，可缓解疼痛强度、减少抑郁并减少 FM 对生活的影响。达到 MCID 与刺激部位和目标症状有关。