The Underlying Mechanism of Communication Deficits in Children and Adolescents with Autistic Spectrum Disorders
Date Issued
2011
Date
2011
Author(s)
Hsu, Wan-Lin
Abstract
Purpose: According to the DSM-IV and ICD-10 diagnosis criteria, there are three core symptoms of Autistic Spectrum Disorders (ASD) including impairments in social reciprocity, communication deficits, and repetitive/stereotyped behaviors. The present study aimed to explore the underlying mechanism of communication deficits in children and adolescents with ASD by examining their Chinese semantic judgment and brain activity related to language circuitry, and the association between language-related cognitive function and brain activity. Methods: Behavioral paradigm and functional magnetic resonance imaging (fMRI) were used to assess 8- to 18-year-old children and adolescents with clinical diagnosis of ASD and age-, sex- and IQ-matched typically developing (TD) children and adolescents (the ASD group vs. the TD group for Experiment 1a; the ASD group with a more severe communication deficit vs. the ASD group with a less severe communication deficit for Experiment 1b; the ASD group vs. the TD group for Experiment 2). The parents reported about their children with ASD by using the Autism Diagnostic Interview-Revised (ADI-R) and the Social Communication Questionnaire (SCQ). Three kinds of Chinese semantic association task with varied strength of association (stronger, weaker, and unrelated) were used. Participants were asked to determine whether visually presented character pair was related in meaning. Results: In Experiment 1a, lower accuracy and longer reaction times were found for weaker association, as compared to stronger association, in both groups. However, the ASD group responded significantly slower to both stronger and weaker association as compared with the TD group. In Experiment 1b, the ASD group with a more severe communication deficit responded significantly slower to both stronger and weaker association relative to those with a less severe communication deficit. In Experiment 2, the ASD group showed reduced activation in left inferior frontal gyrus (IFG, BA 45, 47) as compared with the TD group during semantic processing. Most importantly, for the ASD group, greater activation in right inferior frontal gyrus (IFG, BA 47) was correlated with the severity of clinical syndrome, including the communication measures in the Autism Diagnostic Interview-Revised (ADI-R) interview, and the three ASD cores syndromes in the Social Communication Questionnaire (SCQ). Conclusion: Compared with the TD group, the ASD group performed differently during semantic processing. First, the ASD group showed more difficulties in searching and unifying appropriate semantic features as compared with the TD group. Second, as communication process is related to semantic processing, the ASD group with a more severe communication deficit performed semantic judgments less efficiently relative to those with a less severe communication deficit. Third, the ASD group showed reduced activation in left IFG as compared with the TD group, implying that the ASD group may have a poorer ability in inhibition of irrelevant semantic features and in retrieval/selection of proper semantic features. Fourth, greater activation in right IFG was correlated with the severity of the ASD symptoms, implying that right IFG may play a role in a compensatory mechanism to help the children and adolescents with ASD to meet the demands of semantic judgments for the ASD group.
Subjects
Autism
semantic association strength
fMRI
ADI-R
SCQ
Type
thesis
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