SPEECH AND LANGUAGE PROCESSING IN APHASIA

本研究的主要目的是通过调查失语症患者的言语和语言处理缺陷来识别和描述说话和理解的过程和机制以及神经基质。 研究的主要重点是声音结构和词汇以及将声音映射到意义和意义到声音的处理阶段。 关于将声音映射到意义的加工阶段，有人假设失语症患者的缺陷源于声音结构在词汇中激活的程度。 这种损害的两个潜在来源将被调查，一个集中在词汇本身的激活模式和其他的映射从声音结构到词汇形式。 词汇竞争对词汇加工的影响将通过探讨语音范畴“善良”及其对词汇竞争者激活的影响、词汇密度和频率对词汇决定延迟的影响以及押韵和队列效应对口语词识别时程的影响来研究。 从声音结构到词汇的映射将通过探索声学输入的各种变化对词汇通达的影响来研究，包括声学失真和索引特征（如音高和扬声器）的影响。 实验中使用了多种方法，包括词汇判断、语义启动、辨别和眼动追踪。 关于言语产生的过程和机制，我们假设包括布罗卡氏失语症在内的前失语症患者的言语输出缺陷是以发音实现障碍为基础的。为了进一步描绘出这种损害的性质，将测试三个假设：1。 有人建议，赤字将出现在生产的声音片段，需要在短时间内的发音运动的复杂整合。 研究发音方式的产生，包括塞音、塞擦音、摩擦音和滑音;它提出，赤字协同发音将出现在更大，更复杂的语言环境，特别是跨词的边界。 探讨母音协同发音对前一辅音及辅音发音对前一母音的影响。 本文认为，前失语症患者产生的音位性错语，即语音替代错误，具有语音或发音基础。 在所有这些研究中，声学分析进行了语音生产的前部和后部失语症患者，以推断发音状态引起的声学模式。

The broad goals of this research are to identify and delineate the processes and mechanisms and the neural substrates underlying speaking and understanding by investigating speech and language processing deficits in aphasic patients. The major focus of research is on sound structure and the lexicon and the processing stages that map sound to meaning and meaning to sound. With respect to the processing stages that map sound to meaning, it is hypothesized that the deficits of aphasic patients stem from the extent to which sound structure elicits activation in the lexicon. Two potential sources of such impairment will be investigate, one focusing on activation patterns within the lexicon itself and the other on the mapping from sound structure to lexical form. The influence of lexical competition on lexical processing will be investigated by exploring the effects of phonetic category 'goodness' and its influence on the activation of its lexical competitor, the effects of lexical density and frequency on lexical decision latencies, and rhyme and cohort effects on the time course of spoken word recognition. The mapping from sound structure to the lexicon will be investigated by exploring the influence of various changes to the acoustic input on lexical access including the influence of acoustic distortion and indexical features such as voice pitch and speaker. Various methods will be used including lexical decision, semantic priming, discrimination, and eye tracking. With respect to the processes and mechanisms contributing to speech production, it is hypothesized that the speech output deficits of anterior aphasics including Broca's aphasics have as their basis impairments in articulatory implementation. To further map out the nature of this impairment, three hypotheses will be tested: 1. It is proposed that deficits will emerge in the production of those sound segments that require the complex integration of articulatory movements over short periods of time. The production of manner of articulation including stops, affricates, fricatives, and glides will be investigated; 2. It is proposed that deficits in coarticulation will emerge in larger and more complex linguistic contexts, specifically across word boundaries. The influence of vowel coarticulation on a preceding consonant and consonant articulation on a preceding vowel will be explored; 3. It isproposed that phonemic paraphasias, i.e. sound substitutionerrors, produced by anterior aphasics have a phonetic orarticulatory basis. In all of these production studies,acoustic analyses are conducted of speech productions ofboth anterior and posterior aphasic patients to infer thearticulatory states giving rise to the acoustic patterns.