Background

White matter disconnection of language-specific brain regions associates with worse aphasia recovery. Despite a loss of direct connections, many stroke survivors may maintain indirect connections between brain regions.

Objective

To determine (1) whether preserved direct connections between language-specific brain regions relate to better poststroke naming treatment outcomes compared to no direct connections and (2) whether for individuals with a loss of direct connections, preserved indirect connections are associated with better treatment outcomes compared to individuals with no connections.

Methods

We computed structural whole-brain connectomes from 69 individuals with chronic left-hemisphere stroke and aphasia who completed a 3-week-long language treatment that was supplemented by either anodal transcranial direct current stimulation (A-tDCS) or sham stimulation (S-tDCS). We determined differences in naming improvement between individuals with direct, indirect, and no connections using 1-way analyses of covariance and multivariable linear regressions.

Results

Independently of tDCS modality, direct or indirect connections between the inferior frontal gyrus pars opercularis and angular gyrus were both associated with a greater increase in correct naming compared to no connections (P = .027 and P = .039, respectively). Participants with direct connections between the inferior frontal gyrus pars opercularis and middle temporal gyrus who received S-tDCS and participants with indirect connections who received A-tDCS significantly improved in naming accuracy.

Conclusions

Poststroke preservation of indirect white matter connections is associated with better treated naming improvement in aphasia even when direct connections are damaged. This mechanistic information can be used to stratify and predict treated naming recovery in individuals with aphasia.

中文翻译：

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间接白质通路与失语症的命名改善有关

背景

语言特定大脑区域的白质断开与失语症恢复较差有关。尽管失去了直接联系，但许多中风幸存者可能会在大脑区域之间保持间接联系。

客观的

确定 (1) 与没有直接连接相比，语言特定大脑区域之间保留的直接连接是否与更好的卒中后命名治疗结果相关，以及 (2) 对于失去直接连接的个体，保留的间接连接是否与更好的治疗结果相关与没有联系的人相比。

方法

我们计算了 69 名慢性左半球中风和失语症患者的结构全脑连接组，他们完成了为期 3 周的语言治疗，辅以阳极经颅直流电刺激 (A-tDCS) 或假刺激 (S-tDCS) ）。我们使用协方差和多变量线性回归的单向分析确定了具有直接、间接和无联系的个体在命名改进方面的差异。

结果

独立于 tDCS 模式，与没有连接相比，额下回部分鳃盖部和角回之间的直接或间接连接都与正确命名的更大增加相关（分别为P = .027 和P = .039 ）。接受 S-tDCS 的额下回和颞中回之间有直接联系的参与者和接受 A-tDCS 的间接联系的参与者在命名准确性方面显着提高。

结论

即使直接连接受损，间接白质连接的中风后保留与失语症中更好的命名改善相关。这种机制信息可用于对失语症患者的命名恢复进行分层和预测。