IRCCS, Fondazione Santa Lucia, Rome, Italy.
Department Psychology and Neurosciences, Leibniz Research Center for Working Environment and Human Factors, Dortmund, Germany; Department of Neurology, BG University Hospital Bergmannsheil, Bochum, Germany.
Neuroscience. 2019 May 15;406:159-166. doi: 10.1016/j.neuroscience.2019.03.010. Epub 2019 Mar 12.
High-definition transcranial direct current stimulation (HD-tDCS) is a variant of tDCS, which produces more focal stimulation, delimiting brain current flow to a defined region compared to conventional tDCS. To date, only one study has been conducted to investigate HD-tDCS effects on language recovery in aphasia. Here, we aimed to assess the effects of cathodal HD-tDCS on verb naming by comparing two current intensities: 1 vs 2 mA. In a double-blinded cross over study, two groups of 10 aphasic individuals were submitted to active cathodal HD-tDCS and sham stimulation over the right homolog of Broca's area, while performing a verb naming task. Indeed, we reasoned that, by applying inhibitory current over the right Broca's area, we would decrease the inhibitory impact from the right hemisphere to the left perilesional cortex, thus boosting language recovery. The groups differed in the intensity of the active stimulation (1 mA or 2 mA). In both groups, each condition was carried out in five consecutive daily sessions with one week of interval between the two experimental conditions. A significant improvement in verb naming was found only after cathodal HD-tDCS at 2 mA, which endured one week after the end of treatment. The improvement was not observed on the group receiving cathodal HD-tDCS at 1 mA. Our findings showed that HD-tDCS applied to the right intact hemisphere are efficacious for language recovery. These results indicate that HD-tDCS represents a promising new technique for language rehabilitation. However, systematic determination of stimulation intensity appears to be crucial for obtaining relevant effects.
高清经颅直流电刺激（HD-tDCS）是 tDCS 的一种变体，与传统 tDCS 相比，它产生更集中的刺激，将脑电流限制在一个特定区域。迄今为止，只有一项研究探讨了 HD-tDCS 对失语症语言恢复的影响。在这里，我们旨在通过比较两种电流强度（1 与 2 mA）来评估阴极 HD-tDCS 对动词命名的影响。在一项双盲交叉研究中，两组 10 名失语症患者接受了右侧布罗卡区同源部位的阴极 HD-tDCS 与假刺激，同时进行动词命名任务。事实上，我们推测，通过在右侧布罗卡区施加抑制性电流，我们将减少右侧半球对左侧病灶周围皮质的抑制影响，从而促进语言恢复。两组在主动刺激的强度上有所不同（1 mA 或 2 mA）。在两组中，每个条件都在连续五天的五次治疗中进行，两次实验条件之间间隔一周。仅在 2 mA 的阴极 HD-tDCS 后发现动词命名有显著改善，并且在治疗结束后一周内持续存在。在接受 1 mA 阴极 HD-tDCS 的组中未观察到改善。我们的研究结果表明，应用于右侧完整半球的 HD-tDCS 对语言恢复有效。这些结果表明，HD-tDCS 代表了一种有前途的语言康复新技术。然而，系统确定刺激强度似乎对于获得相关效果至关重要。
