The current study aims to determine the brain areas critical for response to anodal transcranial direct current stimulation (tDCS) in PPA. Anodal tDCS and sham were administered over the left inferior frontal gyrus (IFG), combined with written naming/spelling therapy. Thirty people with PPA were included in this study, and assessed immediately, 2 weeks, and 2 months post-therapy. We identified anatomical areas whose volumes significantly predicted the additional tDCS effects. For trained words, the volumes of the left Angular Gyrus and left Posterior Cingulate Cortex predicted the additional tDCS gain. For untrained words, the volumes of the left Middle Frontal Gyrus, left Supramarginal Gyrus, and right Posterior Cingulate Cortex predicted the additional tDCS gain. These findings show that areas involved in language, attention and working memory contribute to the maintenance and generalization of stimulation effects. The findings highlight that tDCS possibly affects areas anatomically or functionally connected to stimulation targets.

中文翻译：

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脑容量作为原发性进行性失语症 tDCS 效应的预测因子

目前的研究旨在确定对 PPA 中阳极经颅直流电刺激 (tDCS) 反应至关重要的大脑区域。对左侧额下回 (IFG) 进行阳极 tDCS 和假手术，并结合书面命名/拼写疗法。本研究包括 30 名 PPA 患者，并在治疗后立即、2 周和 2 个月进行评估。我们确定了解剖区域，其体积显着预测了额外的 tDCS 效应。对于训练过的词，左角回和左后扣带皮层的体积预测了额外的 tDCS 增益。对于未经训练的词，左额中回、左缘上回和右后扣带回皮层的体积预测了额外的 tDCS 增益。这些发现表明，涉及语言的领域，注意力和工作记忆有助于刺激效果的维持和泛化。研究结果强调，tDCS 可能会影响解剖或功能上与刺激目标相关的区域。