SEMANTIC FEATURE PROCESSING IN INDIVIDUALS WITH STROKE APHASIA

描述（由申请人提供）：单词检索困难是失语症患者最常见的症状，对个体在日常生活中的沟通能力有深远的影响。虽然人们早就认识到对意义或“语义知识”的充分加工是准确词语检索的必要前提，但语义知识加工的缺陷如何影响失语症中所观察到的词语检索困难仍不清楚。长期目标是设计基于语义的治疗失语症的单词检索障碍，最大限度地利用语义信息的类型来促进单词检索。本研究的总体目标是确定语失症患者的语义特征知识、词语检索缺陷和损伤位置之间的关系。该研究的核心假设是：(1)特定语义特征线索的处理缺陷会对那些语义被加权的概念的词检索产生不同的影响；(2)语义特征/概念处理缺陷与病灶定位有关。本项目的基本原理是理解失语症中语义知识与单词检索障碍之间的关系，为扩大临床研究的理论动机评估和治疗缺乏语义引导的词汇检索提供基础。中心假设将通过以下两个具体目标进行检验：(1)确定语义特征线索与不同类型对象概念的单词检索之间的关联；(2)确定语义特征/概念加工与失语症病变位置的关联程度。为了实现这些具体目标，失语症患者将使用神经心理学电池进行评估，该电池旨在直接比较同一生物和非生物物体的特征类型。将收集失语症患者的高分辨率MRI扫描，并将行为表现与病变位置相关。一旦获得这些信息，就有可能区分表现模式，并辨别语义特征治疗的程度，以满足具有不同词检索障碍潜在机制的个体的需求。此外，识别语义特征和对象概念处理之间的相互作用将为正在进行的理论辩论提供信息，即不同类型对象概念处理的损伤是否是与病变位置相关的特征处理缺陷的紧急属性。

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.