Transcranial direct current stimulation (tDCS) is a non-invasive and painless technique of brain neuromodulation that applies a low-intensity galvanic current to the scalp with the aim of stimulating specific areas of the brain. Preliminary investigations have indicated the potential therapeutic efficacy of multisession tDCS applied to the auditory cortex (AC) in the treatment of chronic tinnitus. The aim of this study was to explore the therapeutic effects of repeated sessions of bilateral tDCS targeting the AC on chronic tinnitus. A double-blinded randomized placebo-controlled trial was conducted on patients (n = 48) with chronic intractable tinnitus (>2 years duration). Participants were randomly allocated to two groups: one receiving tDCS (n = 26), with the anode/cathode placed over the left/right AC, and the other receiving a placebo treatment (n = 22). A 20 min daily session of 2 mA current was administered for five consecutive days per week over two consecutive weeks, employing 35 cm2 electrodes. Tinnitus handicap inventory (THI) scores, tinnitus loudness, and tinnitus distress were measured using a visual analogue scale (VAS), and were assessed before intervention, immediately after, and at one-month follow-up. Anodal tDCS significantly reduced THI from 72.93 ± 10.11 score to 46.40 ± 15.36 after the last session and 49.68 ± 14.49 at one-month follow-up in 18 out of 25 participants (p < 0.001). The risk ratio (RR) of presenting an improvement of ≥20 points in the THI after the last session was 10.8 in patients treated with tDCS. Statistically significant reductions were observed in distress VAS and loudness VAS (p < 0.001). No statistically significant differences in the control group were observed. Variables such as age, gender, duration of tinnitus, laterality of tinnitus, baseline THI scores, and baseline distress and loudness VAS scores did not demonstrate significant correlations with treatment response. Repeated sessions of bilateral AC tDCS may potentially serve as a therapeutic modality for chronic tinnitus.

中文翻译：

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听觉皮层重复双侧经颅直流电刺激治疗耳鸣：双盲随机对照临床试验

经颅直流电刺激 (tDCS) 是一种无创、无痛的脑神经调节技术，将低强度电流施加到头皮，目的是刺激大脑的特定区域。初步研究表明，多时段经颅直流电刺激 (tDCS) 应用于听觉皮层 (AC) 治疗慢性耳鸣具有潜在疗效。本研究的目的是探讨重复进行针对 AC 的双侧 tDCS 对慢性耳鸣的治疗效果。对患有慢性顽固性耳鸣（持续时间 >2 年）的患者（n = 48）进行了一项双盲随机安慰剂对照试验。参与者被随机分配到两组：一组接受 tDCS（n = 26），阳极/阴极放置在左/右 AC 上，另一组接受安慰剂治疗（n = 22）。使用 35 cm2 电极，在连续两周内每周连续五天每天施加 20 分钟的 2 mA 电流。使用视觉模拟量表（VAS）测量耳鸣障碍量表（THI）评分、耳鸣响度和耳鸣困扰，并在干预前、干预后立即和一个月随访时进行评估。阳极 tDCS 显着降低了 25 名参与者中 18 名的 THI，从最后一次治疗后的 72.93 ± 10.11 分降至 46.40 ± 15.36，一个月随访时为 49.68 ± 14.49（p < 0.001）。在接受 tDCS 治疗的患者中，最后一次治疗后 THI 改善≥20 分的风险比 (RR) 为 10.8。遇险 VAS 和响度 VAS 显着降低（p < 0.001）。对照组中没有观察到统计学上的显着差异。诸如年龄、性别、耳鸣持续时间、耳鸣偏侧性、基线 THI 评分以及基线痛苦和响度 VAS 评分等变量并未表现出与治疗反应的显着相关性。重复进行双侧 AC tDCS 可能会成为慢性耳鸣的一种治疗方式。