tDCS over the motor cortex improves lexical retrieval of action words in poststroke aphasia
tDCS over the motor cortex improves lexical retrieval of action words in poststroke aphasia
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DOI：
10.1152/jn.00285.2017
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发表时间：
2018-02-01
影响因子：
2.5
通讯作者：
Liuzzi, Gianpiero
中科院分区：
文献类型：
--
作者：
Branscheidt, Meret;Hoppe, Julia;Liuzzi, Gianpiero
全世界三分之一的中风幸存者患有失语症。言语和语言治疗被认为是治疗失语症的有效方法，但由于时间限制，改善往往有限。无创脑刺激是一种很有前途的辅助策略，以促进SLT。然而，中风可能使“经典”语言区域作为刺激点失效。最近的研究表明，运动皮质刺激和强化命名疗法可以有效改善失语症的预后（Meinzer et al. 2016）。尽管这项研究强调了运动皮层的参与，但它影响语言的功能方面仍不清楚。在本研究中，我们关注运动皮层在语言中的作用，探讨其在脑卒中后失语症中特定词汇语义信息（对象与动作关联）获取中的功能参与。为此，我们在一项假对照双盲研究中测试了16例脑卒中后失语症患者左运动皮层经颅直流电刺激（tDCS）对词汇检索的影响。关键刺激包括动作词、目标词和假词。参与者完成了一项词汇决策任务，决定刺激物是单词还是假单词。阳极tDCS提高了词汇决策的准确性，特别是对于具有动作相关内容的词和以“动作”结尾的假词（t(15) = 2.65, P = 0.036），但对于具有对象相关内容的词和具有“对象”特征的假词则没有提高。我们表明，作为一个原则证明，运动皮层可能在获取词汇语义内容中发挥特定作用。因此，在脑卒中后失语症的语言治疗过程中，运动皮层刺激可能会增强内容特异性的词-语义概念关联。运动皮层（MC）在语言处理中的作用在健康和疾病两方面都有争议。最近的研究表明，脑皮层刺激结合言语和语言治疗可以提高失语症的治疗效果。研究表明，脑皮层刺激对脑卒中后失语症的客体和动作字加工有不同的影响。我们认为脑皮层刺激可能会特异性地增强失语症的词-语义概念关联。我们的研究结果可能为语言康复提供一种量身定制的治疗方法。
One-third of stroke survivors worldwide suffer from aphasia. Speech and language therapy (SLT) is considered effective in treating aphasia, but because of time constraints, improvements are often limited. Noninvasive brain stimulation is a promising adjuvant strategy to facilitate SLT. However, stroke might render "classical" language regions ineffective as stimulation sites. Recent work showed the effectiveness of motor cortex stimulation together with intensive naming therapy to improve outcomes in aphasia (Meinzer et al. 2016). Although that study highlights the involvement of the motor cortex, the functional aspects by which it influences language remain unclear. In the present study, we focus on the role of motor cortex in language, investigating its functional involvement in access to specific lexico-semantic (object vs. action relatedness) information in poststroke aphasia. To this end, we tested effects of anodal transcranial direct current stimulation (tDCS) to the left motor cortex on lexical retrieval in 16 patients with poststroke aphasia in a sham-controlled, double-blind study design. Critical stimuli were action and object words, and pseudowords. Participants performed a lexical decision task, deciding whether stimuli were words or pseudowords. Anodal tDCS improved accuracy in lexical decision, especially for words with action-related content and for pseudowords with an "action-like" ending (t(15) = 2.65, P = 0.036), but not for words with object-related content and pseudowords with "object-like" characteristics. We show as a proof-of-principle that the motor cortex may play a specific role in access to lexico-semantic content. Thus motor-cortex stimulation may strengthen content-specific word-to-semantic concept associations during language treatment in poststroke aphasia.NEW & NOTEWORTHY The role of motor cortex (MC) in language processing has been debated in both health and disease. Recent work has suggested that MC stimulation together with speech and language therapy enhances outcomes in aphasia. We show that MC stimulation has a differential effect on object-and action-word processing in poststroke aphasia. We propose that MC stimulation may specifically strengthen word-to-semantic concept association in aphasia. Our results potentially provide a way to tailor therapies for language rehabilitation.