Structural and Effective Connectivity of Reorganized Language Networks in Aphasia

失语症重组语言网络的结构和有效连接

• 批准号: 9327768
• 负责人: Erin Lynn Meier
• 金额: $ 4.4万
• 依托单位: BOSTON UNIVERSITY (CHARLES RIVER CAMPUS)
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-01-15 至 2019-01-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9327768
• 关键词: Address; Affect; Age; Anatomy; Anisotropy; Anterior; Aphasia; Area; Automobile Driving; Behavior; Behavioral; Bilateral; Brain; Brain Injuries; Brain region; Characteristics; Chronic; Communication; Complex; Conflict (Psychology); Consensus; Data; Diffusion Magnetic Resonance Imaging; Foundations; Functional Imaging; Future; Goals; Health; Homologous Gene; Impairment; Individual; Inferior frontal gyrus; Information Networks; Language; Language Disorders; Language Tests; Language Therapy; Left; Lesion; Life; Link; Literature; Location; Measures; Mediating; Methodology; Methods; Middle frontal gyrus structure; Modeling; Names; Nature; Outcome; Pathway Analysis; Pathway interactions; Pattern; Performance; Persons; Prediction of Response to Therapy; Process; Quality of life; Recovery; Recruitment Activity; Research; Role; Semantics; Space Models; Stroke; Structure of middle temporal gyrus; Sum; Task Performances; Testing; Tissues; Work; base; causal model; cognitive function; executive function; improved; innovation; interest; language impairment; language processing; network models; neurobehavioral; neurophysiology; novel; prognostic; relating to nervous system; response; semantic processing; skills; stroke survivor; treatment response; white matter

PROJECT SUMMARY Aphasia affects approximately one-third of stroke survivors and persists in about 15% of these individuals, resulting in debilitating, life-long impairments in functional communication and severely diminished quality of life. Research has shown that despite persistent deficits, persons with chronic aphasia (PWA) can demonstrate improved language skills with concomitant neurophysiological changes following language therapy. However, response to treatment is variable and there is currently no way to predict the degree to which PWA may recover. One reason for the difficulty in predicting aphasia outcomes is that the mechanisms of beneficial neural reorganization of language are unclear. Specifically, optimal language recovery has been linked to activation in left hemisphere (LH) tissue, yet the specific regions that drive improved performance and the cognitive functions they mediate (i.e., language-specific versus domain-general processes) are unknown. Even less is understood regarding the role of the right hemisphere (RH) in reorganization. Some evidence suggests RH activity for language is maladaptive while other findings indicate RH recruitment is essential when LH lesions are large or when aphasia is severe. This traditional LH versus RH debate appears to oversimplify a complex problem. The alternative, central hypothesis of the proposed research is that language reorganization involves the dynamic recruitment of intact tissue within a bilateral network of anatomically-segregated but functionally and structurally connected language-specific and domain-general brain regions. This hypothesis will be tested through two specific aims. First, effective connectivity (which reflects the causal influence of activated regions on other areas) of a bilateral brain network for two related language tasks (i.e., picture naming and semantic feature verification) will be examined via Dynamic Causal Modeling (DCM) in 45 PWA and 35 age-matched controls. We will test the hypothesis that the most active hubs and modulatory regions for both tasks will be domain-general left middle frontal gyrus (LMFG) for PWA and language-specific left inferior frontal gyrus (LIFG) for controls and that best-fit brain models for PWA will include stronger inter-hemispheric interactions than best- fit models in controls. Second, we will examine the extent to which PWAs’ language network structural integrity and task-based connectivity predict their language abilities. We will test the hypothesis that greater effective and structural connectivity of anterior regions within the bilateral network predict better language abilities while stronger connectivity of only intra-RH connections will be predictive of poor performance. By achieving these aims, this project will advance our understanding of the nature of beneficial neural reorganization of language in stroke-induced chronic aphasia. Ultimately, such findings can be incorporated into future work to improve our prognostication of long-term recovery and response to therapy in PWA.

项目摘要 失语症影响了大约三分之一的中风存活，并持续其中约15％ 个人，导致衰弱的功能沟通中的终生障碍，并严重减少 生活质量。研究表明，欲望持续的缺陷，患有慢性失语（PWA）的人可以 在语言治疗后，展示了提高的语言技能，并具有伴随的神经生理学变化。 但是，对治疗的反应是可变的，目前无法预测PWA的程度 可以恢复。难以预测失语症结果的原因之一是有益的机制 语言的神经重组尚不清楚。具体而言，最佳语言恢复已链接到 左半球（LH）组织的激活，但是驱动性能提高的特定区域和 他们介导的认知功能（即语言特定的与领域的过程）尚不清楚。甚至 关于右半球（RH）在重组中的作用的理解较少。一些证据表明 语言的RH活动是适应不良的，而其他发现表明当LH病变时，RH招募至关重要 很大，或者失语症很严重。这场传统的LH与RH辩论似乎过分简化了一个复杂的 问题。拟议研究的替代性，核心假设是语言重组涉及 在解剖学分离但功能和功能和 结构连接的语言特异性和领域将大脑区域。该假设将进行检验 通过两个具体的目标。首先，有效的连通性（反映了活化区域的因果影响 在其他领域）双边大脑网络的两个相关语言任务（即图片命名和语义 功能验证）将通过45个PWA和35岁年龄匹配的动态因果建模（DCM）检查 控件。我们将测试以下假设 PWA和语言特异性左额回（LIFG）的域左中额回（LMFG） 对于控件和PWA的最佳拟合大脑模型，将包括比最佳的杂型间相互作用 在控件中拟合模型。其次，我们将研究PWA的语言网络结构完整性的程度 基于任务的连接性预测了他们的语言能力。我们将检验以下假设，即更有效和 双边网络内前区域的结构连通性预测更好的语言能力 仅RH内部连接的连通性更强将可以预测性能差。通过实现这些 目的，该项目将促进我们对有益神经重组语言重组本质的理解 中风引起的慢性失语症。最终，这些发现可以纳入以后的工作中，以改善我们的 长期恢复和对PWA治疗的反应的预后。