汉语阅读障碍儿童眼跳自主控制缺陷的脑神经机制研究

Abnormal eye movements during reading has been demonstrated in the children with reading disability (RD) in alphabetic and Chinese languages. However, the causes of their abnormal performance in eye movements and its possible neural mechanisms remain unexplained. Previous studies by our team show that Chinese children with RD have abnormal saccadic patterns during reading: their saccade amplitude and mean saccade distance were shorter than typically developping children, which is definitely relevant to their reading difficulty. Therefore it was postulated that abnormal saccadic patterns are related to the abnormal voluntary control of saccades, and the neurological foundation may involve dysfunction of the FEF、SEF and prefrontal cortex. To verify the hypothesis, anti-saccade task and memory-guided saccade task are used to explore the characteristics of voluntary control of saccadic eye movements, and employ Block Design of anti-saccade task and fMRI to investigate the brain network connections of voluntary control of saccades. The aims of this study as following：① To investigate the defective profile of voluntary control of saccades and identity the parameters of voluntary control of saccades which could be used as the diagnosis indexes of reading disability. ② To further understand the role of abnormal saccades played in the cause of reading disability and its potential cognitive factors. ③To illustrate the brain neural mechanisms of abnormal control of saccades. This study, to some extent, promises to reveal pathogenesis of abnormal saccades of the children with RD, and provides theoretical bases and technical references for the clinical prevention and treatment of RD.

已明确表音文字和汉语阅读障碍（RD）儿童阅读时均存在异常眼动，但其原因及可能的神经机制尚不清楚。我们发现，汉语RD儿童阅读时存在特定的眼跳缺陷模式：眼跳幅度小，眼跳距离短，该缺陷是导致RD阅读困难的重要原因，推测与其眼跳自主控制功能异常有关，神经学基础可能涉及大脑FEF、SEF及前额叶皮层功能失调。为验证该假设，本研究拟采用反向眼跳和记忆导向眼跳实验，探索汉语RD儿童眼跳自主控制缺陷特征；利用fMRI技术，采用反向眼跳任务的"Block Design"设计和静息态设计，探索被试眼跳自主控制缺陷的脑区定位和功能连接。目的如下：①了解汉语RD儿童眼跳自主控制缺陷模式，甄别哪些眼跳参数可作为RD诊断指标；②进一步明确异常眼跳在RD发病中的作用及可能的认知影响因素；③探索汉语RD异常眼跳的脑神经基础。该研究将在一定程度上揭示RD异常眼跳的发病机制，为其针对性防治措施的建立提供理论依据和技术参考。

已明确表音文字和汉语阅读障碍（RD）儿童阅读时均存在异常眼动，但其原因及可能的神经机制尚不清楚。我们发现，汉语RD儿童阅读时存在特定的眼跳缺陷模式：眼跳幅度小，眼跳距离短，该缺陷是导致RD阅读困难的重要原因，推测与其眼跳自主控制功能异常有关，神经学基础可能涉及大脑FEF、SEF及前额叶皮层功能失调。为验证该假设，本研究拟采用反向眼跳和记忆导向眼跳实验，探索汉语RD儿童眼跳自主控制缺陷特征；利用fMRI技术，采用反向眼跳任务的“Block Design”设计和静息态设计，探索被试眼跳自主控制缺陷的脑区定位和功能连接。目的如下：①了解汉语RD儿童眼跳自主控制缺陷模式，甄别哪些眼跳参数可作为RD诊断指标；②进一步明确异常眼跳在RD发病中的作用及可能的认知影响因素；③探索汉语RD异常眼跳的脑神经基础。. 认知和眼动结果发现，汉语RD存在语音工作记忆和执行抑制功能缺陷，不存在视空间工作记忆缺陷，但只有语音工作记忆能显著预测RD；在stroop任务中，眼动缺陷模式表现为眼跳距离短、眼跳次数和注视次数多、注视频率慢，这些异常指标不受任务类型的影响，说明抑制功能缺陷不能解释其异常眼动。反向眼跳任务也是反应执行抑制功能的经典范式，我们的结果表明，汉语RD儿童在朝向和反向眼跳中均表现出异常的眼跳模式：注视次数少，瞳孔直径小，平均注视时间短。再次说明抑制功能缺陷不能解释其异常眼动。在反向眼跳的零范式中，RD儿童表现出方向错误率显著高于正常儿童，在其他范式中不存在该指标异常，说明汉语RD儿童眼跳控制存在一定缺陷，但该缺陷不是其核心缺陷。综上，推测中央抑制功能缺陷不是导致汉语RD异常眼跳的核心机制。. 病因学分析发现，小学生识字量与其多动和品行问题关系密切，早产、小于胎龄是导致阅读障碍的重要因素，早期良好的父母养育方式和追赶生长有利于提高早产、小于胎龄儿后期的学业成绩。. 我们本次研究在一定程度上揭示了汉语RD的病因机制，为其针对性防治措施的建立提供理论依据和技术参考。