Theory-driven treatment of language and cognitive processes in aphasia

项目摘要 本研究的目的是翻译一个理论的认知关系的动词短期 失语症的短时记忆和文字处理障碍与语言障碍的治疗方法 在失语症中。 失语症通常被认为是一种语言障碍，但它总是伴随着一个 言语短时记忆能力下降。 基于我们对词汇加工和言语短时记忆损伤的研究， 失语症，我们已经提出，这些障碍的共同发生是由于认知功能的破坏， 支持这两种能力的过程：维持激活的语义和语音表征， 即“激活-维持假说”（Martin & Saffran，1997~ Martin，2008）。我们将测试 这一假设的背景下，治疗方法，旨在改善文字处理和口头STM 能力. 最近，治疗研究作为语言理论的重要试验场的重要性 已经强调了处理（Nickels等人，2010年）。 尽管我们已经证明了 在文字处理损伤和言语短时记忆能力降低之间，激活-维持 一个假设假定了激活语义和语音的维持之间的因果关系 表征和文字处理和口头STM的完整性。直接治疗以改善 保持激活单词表征的能力将作为对这一假设的更强有力的检验。一是 将建立实证支持的假设，损害短期维持激活 单词的语义和语音表征损害失语症患者的语言和言语短时记忆能力， 直接治疗这种缺陷将提高这两种能力（具体目标1）。 这种支持将在 一项短期促进研究和两项在一定条件下使用重复言语刺激的治疗研究 这增加了内存负载。 我们还预测，在语言训练任务中增加记忆负荷， 提高训练任务（重复）以及其他共享处理的语言任务的表现 重复的道路。其次，我们将比较两种给药方式下的治疗效果 高强度和低强度条件（具体目标2）。最近的证据表明，语言治疗是 当以更强烈的时间表给药时更有效（Bhogal等人，2003年），但更多的证据表明， 直接比较高强度和低强度治疗方案的研究。最后我们将 研究了语义短时记忆和语音短时记忆相关神经区域， 症状映射（Bates等人，2003年）（具体目标3）。 根据最近的功能性MRI研究（例如，希夫德 & Alfrepson-Schill，2004），我们预测，减少语义STM将与下额叶 顶叶病变和语音短时记忆减退伴左上级顶叶病变。 这个项目 代表了一种独特的尝试，将最近的失语症处理理论应用于这种疾病的治疗。 研究结果对失语症康复研究具有重要意义。

Project Summary This aim of this research is to translate a theory of the cognitive relationship between verbal short-term memory (STM) and word processing impairments in aphasia to treatment approaches for language impairment in aphasia. Aphasia is typically viewed as a language disorder and yet it is invariably accompanied by a reduction in verbal STM capacity. Based on our research of word processing and verbal STM impairments in aphasia, we have proposed that the co-occurrence of these impairments is due to a disruption of cognitive processes that support both abilities: maintenance of activated semantic and phonological representations of words, hereafter the 'activation-maintenance hypothesis' (Martin & Saffran, 1997~ Martin, 2008). We will test this hypothesis in the context of a treatment approach that aims to improve word processing and verbal STM abilities. Recently, the importance of treatment research as a critical testing ground for theories of language processing has been emphasized (Nickels et al., 2010). Although we have demonstrated associations between impairments of word processing and reduced verbal STM capacity, the activation-maintenance hypothesis presumes a causal association between maintenance of activated semantic and phonological representations and the integrity of both word processing and verbal STM. Direct treatment to improve the ability to maintain activation of word representations will serve as a stronger test of this hypothesis. First, we will establish empirical support for the hypothesis that impairment to short-term maintenance of activated semantic and phonological representations of words impairs language and verbal STM abilities in aphasia and that direct treatment of this deficit will improve both abilities (Specific Aim 1). This support will be obtained in a short-term facilitation study and two treatment studies that use repetition of verbal stimuli under conditions that increase memory load. We also predict that increasing memory load in language training tasks will improve performance on the training task (repetition) as well as other language tasks that share processing pathways with repetition. Second, we will compare effects of this treatment under two administration conditions, high and low intensity (Specific aim 2). Recent evidence suggests that language treatments are more effective when administered on more intense schedules (Bhogal et al., 2003), but more evidence is needed from studies that directly compare high and low intensity schedules of treatment. Finally, we will investigate neural regions associated with semantic STM and phonological STM using voxel-based lesion- symptom mapping (Bates et al., 2003) (Specific Aim 3). Following recent functional MRI studies (e.g., Shivde & Thompson-Schill, 2004), we predict that reduced semantic STM will be associated with inferior frontal parietal lesions and reduced phonological STM with lesions in the left superior parietal region. This project represents a unique attempt to apply more recent processing theories of aphasia to treatment of the disorder. The outcomes will have important implications for aphasia rehabilitation research.