SEMANTIC FEATURE PROCESSING IN INDIVIDUALS WITH STROKE APHASIA

描述(申请人提供)：单词提取困难是失语症患者最常见的症状，对个人在日常生活中的交流能力有深远的影响。虽然人们很早就认识到，对意义的充分处理或“语义知识”是准确单词提取的必要先导，但对语义知识的不足处理如何影响失语症中观察到的单词提取困难仍不清楚。长期目标是为失语症中的单词提取障碍设计基于语义的治疗方法，使用于促进单词提取的语义信息类型最大化。这个项目的总体目标是确定失语症患者的语义特征知识、单词提取缺陷和病变位置之间的关系。中心假设是：(1)对特定语义特征线索的加工不足会对语义偏向于这些特征的概念的词提取产生不同的影响；(2)语义特征/概念加工不足与病变位置有关。该项目的基本原理是，了解失语症患者的语义知识与词提取障碍之间的关系，将为扩大临床研究的基础，从理论上评估和治疗语义引导词汇提取缺陷的临床研究。中心假设将通过追求以下两个具体目标来检验：(1)确定不同类型客体概念的语义特征线索与词提取之间的关联；(2)确定语义特征/概念加工与失语症中病变位置的关联程度。为了实现这些特定的目标，失语症患者将使用神经心理学组件进行评估，该组件旨在提供相同生命物体和非生命物体中特征类型的直接比较。失语症参与者的高分辨率MRI扫描将被收集，行为表现将与病变位置有关。一旦获得了这一信息，就有可能区分不同的表现模式，并辨别语义特征治疗可能在多大程度上被定制以满足具有不同潜在单词提取障碍机制的个体的需要。此外，识别语义特征和客体概念加工之间的相互作用将有助于正在进行的理论辩论，即不同类型客体概念的加工损伤是否是与病变位置有关的特征加工缺陷的紧急性质。 公共卫生相关性：拟议的研究将对理解如何最好地设计基于个体处理语义特征线索的能力的理论动机的临床工具来补救单词提取障碍产生重要的积极影响。拟议的项目与公共卫生相关，因为要调查的机制将为制定单词提取障碍的评估和治疗提供信息，这些障碍可能会影响失语症患者日常生活中的沟通。

DESCRIPTION (provided by applicant): Word retrieval difficulty is the most common symptom observed in people with aphasia, having a profound impact on individuals' ability to communicate in daily life. While it has long been acknowledged that adequate processing of meaning or "semantic knowledge" is a necessary precursor to accurate word retrieval, it remains unclear how deficient processing of semantic knowledge influences word retrieval difficulties observed in aphasia. The long-term goal is to design semantically-based treatments for word retrieval impairment in aphasia that maximize the types of semantic information that are utilized to facilitate word retrieval. The overall objective of this project is to determine the relationships among semantic feature knowledge, word retrieval deficits, and lesion location in individuals with aphasia. The central hypothesis is that (1) deficient processing of specific semantic feature cues will differentially impact word retrieval for concepts whose meanings are weighted in favor of those features; and (2) deficient semantic feature/concept processing is associated with lesion location. The rationale for the proposed project is that understanding the relationship between semantic knowledge and word retrieval impairment in aphasia will provide the foundation upon which to expand clinical research into theoretically-motivated assessment and treatment of deficient semantically-guided lexical retrieval. The central hypothesis will be tested by pursuing the following two specific aims: (1) Determine the association between semantic feature cues and word retrieval for different types of object concepts, and (2) Determine the extent to which semantic feature/concept processing is associated with lesion location in aphasia. To pursue these specific aims, individuals with aphasia will be assessed using a neuropsychological battery designed to provide for direct comparison between feature types within the same living and nonliving objects. High resolution MRI scans will be collected for participants with aphasia and behavioral performance will be related to lesion location. Once this information has been obtained, it will be possible to differentiate patterns of performance and discern the extent to which semantic feature treatments may be tailored to meet the needs of individuals with differing underlying mechanisms of word retrieval impairment. Furthermore, identifying the interaction between semantic feature and object concept processing will inform ongoing theoretical debates regarding whether impairment to processing of different types of object concepts is an emergent property of feature-processing deficits that can be linked to lesion location. PUBLIC HEALTH RELEVANCE: The proposed research will have an important positive impact on understanding of how best to design theoretically-motivated clinical tools to remediate word retrieval impairment based on knowledge of individuals' ability to process semantic feature cues. The proposed project has relevance to public health because the mechanisms to be investigated will inform the development of assessments and treatments for word retrieval impairments that can compromise communication in the daily lives of individuals with aphasia.