基于EEG相干性和磁共振影像的孤独症儿童脑区连通性研究

Autism is a severe neurodevelopmental disorders, which is obviously increasing prevalence in recent years and has become a global public health problem of influencing the health of children. More researchers focus on the pathogenesis and intervention of autism. Recently, particular attention was paid to structural abnormalities of autism and brain connectivity, especially the abnormal integrity of white matter fiber bundles connected various regions of the brain, which would result in dysfunction of brain execution. EEG coherence is considered to be an important indicator of the connectivity of brain regions. The study's objective was to 1) compare the differences of intrahemispheric and interhemispheric EEG coherence between healthy and autistic children with auditory event stimulation; 2) investigate correlation between severity of brain dysfunction and clinical phenotypes of children with autism. In addition, imaging technology will be used to compare the high-functioning brain morphology and development of white matter fiber tracts from autistic children and healthy children, in order to further clarify the mechanism underlying autistic abnormal brain function and provide potential medical imaging and electrophysiological evidences for autistic diagnosis.

孤独症谱系障碍是一种严重的神经发育障碍性疾病，近年来患病人数递增，已成为严重影响儿童健康的全球公共卫生问题。较多学者致力于其发病机制和综合干预方面的研究。目前，针对孤独症儿童大脑连通性异常已经引起关注，大脑结构异常尤其脑白质纤维束的完整性影响着大脑各区域的连通性，这种结构异常直接导致大脑的执行功能异常。EEG的相干性目前被认为是评价脑区连通性的重要指标。本研究拟探讨在接受听觉事件刺激的条件下，孤独症儿童半球内部不同脑区和半球间不同脑区各个频段的EEG相干性及其与正常儿童的异同，并分析脑功能异常的区域和程度与孤独症儿童的临床表型特征的相关关系；此外，采用影像学技术，比较高功能孤独症脑形态学及脑白质纤维束发育情况及与正常儿童的差异，进一步明确孤独症儿童脑功能异常机制，为探索孤独症诊断的EEG标志性信号提供影像学及电生理学依据。

孤独症谱系障碍是一种严重的神经发育障碍性疾病，起病于婴幼儿时期，已成为严重影响儿童健康的全球公共卫生问题。其神经基础成为病因学研究的热点，大量神经影像及神经电生理研究发现孤独症谱系障碍患者大脑结构和功能均存在异常。本研究从结构和功能结合的出发点，研究孤独症儿童大脑灰质及白质结构异常，并以EEG的相干性为指标，评价孤独症儿童在静息及听觉刺激条件下脑区连通性。通过核磁共振影像学方法发现孤独症谱系障碍儿童的大脑结构与正常儿童存在显著差异，主要体现在左侧颞上回和左侧中央后回为主的脑灰质体积增大；大脑左侧前放射冠、胼胝体体部、左侧上放射冠、左侧内囊后肢等部位的脑白质纤维束的各向异性分数（fractional anisotropy，FA）显著降低。神经电生理结果也发现孤独症谱系障碍儿童与正常儿童的脑电相干性存在显著差异，孤独症组儿童脑电相干性在静息状态和听觉刺激条件下均大于正常儿童，表现出过度连接的趋势，并且这种趋势在大脑半球内和半球间都有同样体现。以上结果均不同程度的表现出与孤独症临床症状存在相关性。本研究为探索孤独症谱系障碍儿童脑结构和功能异常提供了有力的线索，为标志性诊断指标体系的建立提供了影像学及电生理学依据。