Speech Motor Planning in Apraxia of Speech and Aphasia

 描述(申请人提供)：言语失用症(AOS)是一种运动性言语障碍，对一个人的沟通和参与日常生活的能力造成严重障碍。现有的AOS理论都认为语言障碍会影响言语运动计划阶段，即语言表征被转化为言语运动的阶段，但他们对这一加工水平上的障碍的具体性质并不一致(Ziegler，2002)。更详细地了解这种损害对于开发有针对性的、有效的治疗方法和确定这些治疗的适当候选者是至关重要的。AOS的研究因以下事实而变得复杂：这种疾病很少单独发生，但通常伴有不同程度的失语症(一种语言障碍)和/或构音障碍(一种言语运动控制的神经肌肉障碍)。此外，AOS与其最接近的临床邻居失语症和音素性失语的行为相似，削弱了传统方法(如知觉错误分析)在这两种疾病研究中的有效性。本研究的目的是验证两种相互矛盾的假说，即AOS中言语运动规划障碍的具体性质。该项目是在一个成熟的言语产生理论框架的背景下制定的，它结合了心理语言学的反应时范式和认知神经心理学的方法。这种研究AOS的创新方法很有前途，原因如下。首先，心理语言学的反应时方法在提高我们对正常说话者的言语运动计划的理解方面发挥了重要作用，但它们很少被应用于对有神经损伤的人的研究。其次，这种结合的方法通过关注不同言语运动规划条件下同一行为的起始潜伏期，避免了不同障碍中错误模式的行为相似性问题。一些初步研究表明，患有AOS的人和没有AOS的失语症患者的反应时模式不同，这支持了这一系统研究路线在鉴别诊断方面的潜在用途。这项研究项目的成功完成将为AOS的特定运动规划障碍提供新的信息。到目前为止，关于AOS的损害已经提出了不同的具体假设，但它们还没有在一系列系统的实验中用相同的方法进行直接相互验证。此外，拟议的研究项目将通过比较AOS患者和失语患者的研究结果，来测试AOS患者言语运动规划障碍的特异性。这些发现将为改善AOS和失语症患者的诊断工具和治疗方案提供关键的、具有理论动机的基础，从而提高临床决策能力。这种旨在开发敏感和特定的诊断工具和改进治疗方案的转化和临床研究是这位候选人研究计划的最终长期目标。

 DESCRIPTION (provided by applicant): Apraxia of speech (AOS) is a motor speech disorder that poses significant obstacles to a person's ability to communicate and take part in everyday life. Current theories of AOS agree that the impairment affects the speech motor planning stage, where linguistic representations are transformed into speech movements, but they disagree on the specific nature of the breakdown at this processing level (Ziegler, 2002). A more detailed understanding of this impairment is essential for developing targeted, effective treatment approaches and for identifying the appropriate candidates for these treatments. The study of AOS is complicated by the fact that this disorder rarely occurs in isolation but is commonly accompanied by various degrees of aphasia (a language impairment) and/or dysarthria (a neuromuscular impairment of speech motor control). In addition, the behavioral similarities of AOS and its closest clinical neighbor, aphasia with phonemic paraphasias, undermine the usefulness of traditional methods, such as perceptual error analysis, in the study of both disorders. The purpose of the present proposal is to test two competing hypotheses about the specific nature of the speech motor planning impairment in AOS. The project is formulated in the context of a well-established theoretical framework of speech production and it combines psycholinguistic reaction time paradigms with a cognitive neuropsychological approach. This innovative approach to the study of AOS is promising for the following reasons. First, psycholinguistic reaction time methods have had an important role in improving our understanding of speech motor planning in unimpaired speakers, but they have rarely been applied to the study of people with neurologic impairments. Second, this combined approach circumvents the problem of behavioral similarity of error patterns in different disorders by focusing on the onset latencies of the same behavior under different speech motor planning conditions. A few initial studies have suggested different reaction time patterns between people with AOS and people with aphasia without AOS, supporting the potential utility of this systematic line of research in regard to differential diagnosis. The successful completion of this research project will yield novel information about the specific motor planning impairment in AOS. To date, different specific hypotheses about the impairment in AOS have been proposed but they have not been directly tested against each other with the same methods in a systematic succession of experiments. In addition, the proposed research project will test the specificity of the speech motor planning impairment in speakers with AOS by comparing the findings from speakers with AOS to those from speakers with aphasia. These findings will form a critical, theoretically-motivated basis for improving diagnostic tools and treatment protocols for people with AOS and aphasia, thus enhancing clinical decision- making. Such translational and clinical research aimed at developing sensitive and specific diagnostic tools and improving treatment protocols is the ultimate long-term objective of this candidate's research program.