Gilmore Natalie, Yücel Meryem Ayse, Li Xinge, Boas David A, Kiran Swathi
Department of Speech Language & Hearing Sciences, Sargent College of Health and Rehabilitation Sciences, Boston University, Boston, MA, United States.
Neurophotonics Center, Biomedical Engineering, Boston University, Boston, MA, United States.
Front Hum Neurosci. 2021 Sep 17;15:728151. doi: 10.3389/fnhum.2021.728151. eCollection 2021.
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.
与中风后语言恢复相关的大脑重组模式长期以来一直存在争议。鉴于中风后失语症患者可能会募集病灶周围的左半球语言区域、同源的右半球语言区域和/或剩余的双侧通用区域，因此研究中风后失语症患者自发和治疗诱导的语言恢复机制需要采用基于网络的方法。近年来，功能近红外光谱技术（fNIRS）在硬件、软件和方法上取得了进展，使其非常适合研究这个问题。fNIRS具有成本效益且禁忌症极少，是监测治疗相关大脑激活随时间变化的可靠选择。通过fNIRS在神经典型成年人的语言和通用认知过程中建立清晰的激活模式是重要的第一步。一些fNIRS研究调查了健康成年人的关键语言过程，但由于方法学上的局限性，研究结果难以解释。这项初步研究使用fNIRS来捕捉神经典型个体和失语症患者在语言和通用处理过程中的大脑激活情况。这些发现将为未来解释中风后失语症患者治疗相关的大脑激活模式变化提供参考。24名年轻健康对照者、17名年长健康对照者和6名左半球中风所致失语症患者在fNIRS期间完成了两项语言任务（即语义特征、图片命名）和一项通用认知任务（即算术），每项任务各进行两次。探头覆盖双侧额叶、顶叶和颞叶，并包括用于头皮信号干扰回归的短距离探测器。正如预期的那样，年轻和年长的健康对照者在语义特征处理（如左侧额下回 opercularis部）和词汇检索（如左侧额下回 triangularis部）过程中激活了核心语言区域，在难度不同的算术任务中激活了通用区域（如双侧额中回）。与中风后语言恢复理论一致，失语症患者激活了传统网络之外的区域：在语义特征判断期间激活左侧额上回和左侧缘上回；在图片命名期间激活左侧额上回和右侧中央前回；在算术处理期间激活左侧额下回 opercularis部。中风组的初步研究结果突出了使用fNIRS研究失语症患者语言和通用处理的实用性。
