高功能孤独症者非字面语义理解缺陷:隐喻视角的研究

Non-Literal Meaning Comprehension Defect in High-Functioning Autism Spectrum Disorder: An ERP Study Based on Metaphor Perspective

研究采用事件相关电位技术从隐喻语义加工角度考察了高功能孤独症成人非字面语义理解中的行为特点及脑半球参与模式。行为结果显示:高功能孤独症成人对新异隐喻句的反应时最长,两类隐喻句的反应时均长于普通成人,错误率上两组间无差异。脑电结果显示:高功能孤独症组对新异隐喻句的N400波幅最大,未出现半球偏侧化现象,传统隐喻句在左脑的N400波幅大于右脑,两类隐喻句的N400波幅均大于正常被试。结论:高功能孤独症成人具备低效率的隐喻理解能力,隐喻加工的脑半球优势效应异常。

Previous research indicated that there were severe disabilities in non-literal meaning comprehension among people who were diagnosed with Autistic Spectrum Disorder （ASD）. These development defects cause their disability of social cognition and language information processing. In view of the experience of past research, metaphor is an appropriate perspective to explore the defects of non-literal meaning comprehension. For instance, a low efficiency of ASD metaphor semantic integration may be caused by right hemisphere dysfunction or undereonnectivity among different brain regions. All defects of brain structure or brain function impair different kinds of metaphorical comprehension. Recent studies explored the brain defects in metaphorical semantic comprehension from the neural physiological level and mainly among the patients with Asperger＇s syndrome （AS）. However, inconsistent conclusions have been made among the people diagnosed on High Functioning Autism （HFA）. Furthermore, the research participants have been limited to children and little is known on metaphor semantic integration of adults with HFA. In order to examine the neural physiological features of metaphor semantic comprehension among adults with HFA and to make proposals to other research of non-literal meaning comprehension, the present study recruited 20 adults with HFA （mean ages = 19.95 years） and their 20 typically developing peers （mean ages = 19.40 years） who were matched on IQ. Event Related Potential （ERP） was used to investigate the metaphorical semantic processing of four types of sentences including novel-metaphor sentences, conventional-metaphor sentences, literal sentences, and error sentences. All participants were asked to perform a semantic judgment task that required them to decide whether the sentences showed on the computer screen conveyed a meaningful expression or not as quickly and accurately as^possible. The results showed that： HFA adults could comprehend metaphor semantic ultimately with a long response time and a normal accuracy. In the typically developing group, the largest N400 amplitude of error sentences and a right hemisphere advantage effect were found. Novel metaphor sentences had smaller N400 amplitude compared with error sentences but N400 of the former was still larger than the conventional metaphor sentences and literal sentences. This result suggests that the error sentences semantic integration is the most difficult among the typically developing group. A different pattern was observed in the HFA group, and novel metaphor elicited the largest N400 amplitude, which was followed by error sentences, conventional metaphor sentences, and literal sentences. No lateralization effect was found on novel metaphor sentences. The present study suggests that the semantic integration ability in metaphor comprehension among HFA adults is relatively intact, but a different processing pattern has been found compared with their typically developing peers. This special processing pattern may be attributed to right hemisphere dysfunction or poor connectivity among different brain areas or structures.