Table_3_Investigating Language and Domain-General Processing in Neurotypicals and Individuals With Aphasia — A Functional Near-Infrared Spectroscopy Pilot Study.docx

Brain reorganization patterns associated with language recovery after stroke have long been debated. Studying mechanisms of spontaneous and treatment-induced language recovery in post-stroke aphasia requires a network-based approach given the potential for recruitment of perilesional left hemisphere language regions, homologous right hemisphere language regions, and/or spared bilateral domain-general regions. Recent hardware, software, and methodological advances in functional near-infrared spectroscopy (fNIRS) make it well-suited to examine this question. fNIRS is cost-effective with minimal contraindications, making it a robust option to monitor treatment-related brain activation changes over time. Establishing clear activation patterns in neurotypical adults during language and domain-general cognitive processes via fNIRS is an important first step. Some fNIRS studies have investigated key language processes in healthy adults, yet findings are challenging to interpret in the context of methodological limitations. This pilot study used fNIRS to capture brain activation during language and domain-general processing in neurotypicals and individuals with aphasia. These findings will serve as a reference when interpreting treatment-related changes in brain activation patterns in post-stroke aphasia in the future. Twenty-four young healthy controls, seventeen older healthy controls, and six individuals with left hemisphere stroke-induced aphasia completed two language tasks (i.e., semantic feature, picture naming) and one domain-general cognitive task (i.e., arithmetic) twice during fNIRS. The probe covered bilateral frontal, parietal, and temporal lobes and included short-separation detectors for scalp signal nuisance regression. Younger and older healthy controls activated core language regions during semantic feature processing (e.g., left inferior frontal gyrus pars opercularis) and lexical retrieval (e.g., left inferior frontal gyrus pars triangularis) and domain-general regions (e.g., bilateral middle frontal gyri) during hard versus easy arithmetic as expected. Consistent with theories of post-stroke language recovery, individuals with aphasia activated areas outside the traditional networks: left superior frontal gyrus and left supramarginal gyrus during semantic feature judgment; left superior frontal gyrus and right precentral gyrus during picture naming; and left inferior frontal gyrus pars opercularis during arithmetic processing. The preliminary findings in the stroke group highlight the utility of using fNIRS to study language and domain-general processing in aphasia.

关于中风后语言恢复相关的脑重组模式，长久以来一直是学界争论的焦点。探究中风后失语症患者自发性及治疗诱导的语言恢复机制，鉴于邻近损伤的左侧大脑半球语言区域、同源右侧大脑半球语言区域，以及/或未被损伤的双侧领域性一般区域的潜在激活，亟需采用基于网络的方法。近年来，功能近红外光谱学（fNIRS）在硬件、软件和方法论方面的最新进展，使其成为研究此问题的理想工具。fNIRS具有成本效益高、禁忌症少的优点，使其成为监测治疗相关脑激活随时间变化的一种稳健选项。通过fNIRS在神经典型成人中建立清晰的激活模式，尤其是在语言和领域性认知过程中的激活模式，是至关重要的第一步。一些fNIRS研究已探究了健康成人中的关键语言过程，但由于方法论限制，其结果在解释时颇具挑战性。本项试点研究利用fNIRS捕捉神经典型成人及失语症患者在进行语言和领域性处理时的脑激活。这些发现将在未来解释中风后失语症中与治疗相关的脑激活模式变化时作为参考。二十四名年轻健康对照者、十七名老年健康对照者以及六名左侧半球中风引起的失语症患者完成了两项语言任务（即语义特征、图片命名）和一项领域性认知任务（即算术）两次，在fNIRS下进行。探针覆盖了双侧额叶、顶叶和颞叶，并包括用于头皮信号混杂项回归的短距离探测器。年轻和老年健康对照者在语义特征处理（例如，左侧颞下回）和词汇检索（例如，左侧颞下回）过程中激活了核心语言区域，在难易算术对比中激活了领域性区域（例如，双侧中央前回），这与预期相符。与中风后语言恢复的理论一致，失语症患者激活了传统网络之外的区域：在语义特征判断时，左侧额上回和左侧上缘回；在图片命名时，左侧额上回和右侧中央前回；在算术处理时，左侧颞下回。中风组中的初步发现突出了使用fNIRS研究失语症中语言和领域性处理的有用性。