Neurophysiological Measurement in Aphasia Treatment

功能磁共振成像（fMRI）和弥散张量成像（DTI）可以帮助表征失语症患者的神经生理状态。这些测量可用于开发治疗方法，选择针对特定患者的治疗方法，并衡量治疗的有效性。然而，失语症的脑成像必须得到改善。fMRI和DTI对头部运动和口咽运动都高度敏感，而这些伪影在非流利性失语症患者中会加剧，因为他们说话更困难。中风通常由脉管系统的改变引起或伴有脉管系统的改变，从而影响MRI信号。血流动力学的再分布导致MRI信号来源的模糊，这些信号被认为是指示神经重组和/或重塑的信号。再灌注出血引起的伪影导致病灶附近的敏感性伪影。这项工作将专门解决这些技术问题，以促进在失语症患者中使用神经生理（功能成像）测量。

Both functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) can be helpful in characterizing the neurophysiological status of patients with aphasia. Such measurements can be used to develop treatment approaches, select patient-specific treatments, and gauge the effectiveness of treatment. However, brain imaging in aphasia must be improved. Both fMRI and DTI are highly sensitive to both head motion and oropharyngeal motion, and these artifacts are exacerbated in patients with non-fluent aphasia, who have a more difficult time producing speech. Stroke is often precipitated by and/or accompanied by alterations in vasculature, which can affect the MRI signal. Hemodynamic redistribution leads to ambiguity about the source of MRI signals presumed to indicate neural reorganization and/or remodeling. Artifacts from reperfusion hemorrhage leads to susceptibility artifact in the vicinity of lesions. The proposed work will specifically address each of these technical issues to facilitate the use of neurophysiological (functional imaging) measures in patients with aphasia. For fMRI and DTI to guide therapeutic decision-making, there must be formal ways to characterize the physiological state of individual patients and to correlate biological and behavioral parameters. In this proposal, we develop two classes of measures, scalar indices and network activation maps, and investigate their relationship to measures of speech and language. Scalar indices reduce an entire pattern of activation into a single number, such as degree of brain lateralization or integrity of callosal white matter. Network maps include structural equation models and Euclidean distance maps, and we develop methods to compare such large-scale models between individuals or groups (e.g., patients who do and do not benefit from therapy). This component of the research aims to develop rational neurophysiological measures for aphasia research. Finally, these methodological improvements will be applied to a treatment study for patients with chronic non-fluent aphasia and left frontal lesions. The therapeutic intervention is based on (a) neurobiological observations that the brain has circuits particularly active in motor imitation through observation-execution matching, including oral motor imitation; (b) behavioral observations that imitation is a cornerstone of many treatments for non-fluent aphasia; and (c) treatment data that favor intensive approaches and graded incremental learning. Outcomes are assessed by both physiological and behavioral measures, which are collected every three weeks starting six weeks before treatment and ending six weeks after completion of treatment.