ABSTRACT

Background

It is not conclusively explored what kind of reorganisation processes are set off after a stroke with resulting aphasia. Since the development of functional Magnetic Resonance Imaging (fMRI), linguistic processes and their neural representation have been researched, especially in aphasic patients after left hemispheric insult. The situation differs in aphasic patients with crossed aphasia or aphasia after a right hemispheric lesion, for which only few studies have been carried out. In order to close this gap, the present study deals with the localisation of language functions in the brain of patients with crossed aphasia and right hemispheric language dominance.

Aim

The objective of the current study was to provide insights into the neural correlates of continuous aphasic language production of patients with right hemispheric language dominance. Based on the current state of research, a mirror image representation was expected.

Methods & Procedures

Two patients with fluent aphasia due to right hemisphere lesions, one presenting with crossed aphasia, described complex pictures. The continuous language output was transcribed and categorised into events. Lexical search (i.e. the difference between unimpaired speaking and word-finding difficulties) was analysed using fMRI. The neural activation clusters were compared with the corresponding areas of a control group consisting of 12 patients with left hemispheric aphasia.

Outcomes & Results

The analysis of the behavioural data revealed word-finding difficulties as one of the most limiting factors in the spontaneous language output of the patients. The neural correlates of lexical search (unimpaired minus impaired) were observed in four activation clusters both patients had in common. Each cluster was predominantly localised in the contra-lesional hemisphere. Compared to the corresponding areas of the control group, in general, a mirrored image representation could be confirmed.

Conclusions

The combination of detailed linguistic analysis and fMRI confirmed the assumption of mirrored language organisation for anomia in continuous language production. Moreover, the study might add to a more general understanding of the contribution of the contra-lesional hemisphere to language recovery in aphasia after left or right hemisphere damage.

中文翻译：

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两名右半球语言优势患者自发语言产生的神经相关性

摘要

背景

中风导致失语症后会引发什么样的重组过程，目前还没有最终确定。自从功能磁共振成像 (fMRI) 发展以来，语言过程及其神经表征已经得到研究，特别是在左半球损伤后的失语症患者中。交叉性失语症或右半球病变后失语症的失语症患者的情况有所不同，对此仅进行了很少的研究。为了弥补这一差距，本研究涉及交叉性失语症和右半球语言优势患者大脑中语言功能的定位。

目的

本研究的目的是提供对右半球语言优势患者持续失语语言产生的神经相关性的见解。根据目前的研究状态，预计会出现镜像表示。

方法和程序

两名因右半球病变导致流畅性失语症的患者，一名表现为交叉性失语症，描述了复杂的图片。连续的语言输出被转录并分类为事件。使用 fMRI 分析词汇搜索（即未受损的口语和找词困难之间的差异）。将神经激活簇与由 12 名左半球失语症患者组成的对照组的相应区域进行比较。

结果和结果

对行为数据的分析表明，找词困难是患者自发语言输出的最大限制因素之一。在两个患者共有的四个激活簇中观察到词汇搜索（未受损减去受损）的神经相关性。每个簇主要位于病灶对侧半球。与对照组的相应区域相比，通常可以确认镜像表示。

结论

详细的语言分析和 fMRI 的结合证实了镜像语言组织在连续语言产生中的失常假设。此外，该研究可能有助于更全面地了解对侧半球对左半球或右半球损伤后失语症语言恢复的贡献。