Cross-Linguistic Studies of Aphasia

失语症的跨语言研究使我们能够将普遍机制与特定语言内容分开。通过揭示在正常和异常条件下可能发生的变化范围，跨语言研究还解决了行为和神经可塑性的关键问题。在这篇论文中，我们概述了三种语言（英语、意大利语和汉语）在词汇和语法结构（例如词序变化的数量、屈折词形、成分遗漏、单词和语素的一致性与不规则性、词汇歧义的可能性和单词的内部结构）方面存在显著差异的失语症患者和对照组的语言加工和语言分解的新比较研究。病人研究（病变-行为映射的经典方法）辅以同样三种语言的正常人脑成像研究（使用功能性磁共振成像，或fMRI）。同样的材料也被用于行为和功能磁共振实验，在“在线”，计算机控制的任务中，产生关于单词和句子处理的时间动态的信息。非语言控制任务的设计是为了在关键方面（视觉、听觉和运动激活；对记忆、注意力、决策的需求）匹配语言任务，测试关于模态和感觉运动需求对语言激活（fMRI）和语言分解（损伤研究）的贡献的假设。我们还扩展了“正常控制”的概念，以包括在不利处理条件下（感知退化，时间压缩，认知过载）的正常测试的比较，以发现处理中的“断点”并“模拟”患者的处理障碍。文字和图片刺激的选择是基于在上一个资助周期中从所有站点收集的大量规范信息。研究中的失语症亚组包括不流利的布洛卡失语症、流利的韦尼克失语症，以及很少出现明显语法错误但仍在努力“找到合适的单词”的失语症患者。认识到传统失语症分类的局限性，我们还采用了一种新的多变量方法，在连续的多维症状空间中分析患者在实验中的表现，该空间通过使用大型档案数据集（每种语言超过200名患者）为每种语言定义。结果在两个理论框架的合并中得到解释：竞争模型（一种假设分布式、概率表示上的交互激活的处理模型）和体现理论（一种语言神经组织理论）。

Cross-linguistic studies of aphasia permit us to separate universal mechanisms from language-specific content. By uncovering the range of variations that are possible under normal and abnormal conditions, cross-language studies also address the critical issues of behavioral and neural plasticity. In this proposal, we outline new comparative studies of language processing and language breakdown in aphasic patients and controls in three languages (English, Italian and Chinese) that differ dramatically in their lexical and grammatical structure (e.g. amounts of word order variation, inflectional morphology, constituent omission, consistency vs. irregularity of words and morphemes, potential for lexical ambiguity, and the internal structure of words). Patient studies (the classical method of lesion-behavior mapping) are complemented by brain-imaging studies of normals in the same three languages (using functional magnetic resonance imaging, or fMRI). The same materials are used in behavioral and fMRI experiments, in 'on-line', computer- controlled tasks that yield information about the temporal dynamics of word and sentence processing. Nonverbal control tasks are designed to match linguistic tasks in key respects (visual, auditory, and motor activation; demands on memory, attention, decision-making), testing hypotheses about the contributions of modality and sensorimotor demands to language activation (fMRI) and language breakdown (lesion studies). We also expand the concept of "normal control" to include comparisons of normal tested under adverse processing conditions (perceptual degradation, temporal compression, cognitive overload), to uncover 'breakpoints' in processing and to 'simulate' processing disorders in patients. Selection of word and picture stimuli is based on massive norming information collected at all sites in the last funding cycle. The aphasia subgroups under study include nonfluent Broca's aphasics, fluent Wernicke's aphasics, and anomic patients who commit few overt grammatical errors but still struggle to 'find the right word'. Acknowledging the limitations of traditional aphasia categories, we also take a new multivariate approach, analyzing patients' performance on experiments within a continuous, multidimensional symptom space, defined for each language by using large archival data sets (more than 200 patients per language). Results are interpreted within a merger of two theoretical frameworks: the Competition Model (a processing model that assumes interactive activation over distributed, probabilistic representations) and Embodiment Theory (a theory of neural organization for language).