N170作为汉语发展性阅读障碍潜在早期诊断指标的研究

Developmental dyslexia (DD) is the most common learning disability in children and adolescents. This disorder severely hinders individual's development and can be an economic burden on family, society and country. Notably, early diagnosis and intervention is critical for improving the reading ability of dyslexic children. However, there is still no reliable biological marker for early diagnosis of dyslexia. The disability of learning to read is the core and most obvious problem of children with DD. Recently, a series of our own studies and those of others on adults and children especially preschool children, revealed that an event-related potential component (termed as N170) is a reliable electrophysiological marker for expertise in reading words. Thus, the current project proposes a novel hypothesis that the N170 component is an objective biological marker for the early diagnosis of Chinese dyslexic children. Through an aggregate cross-design, the project aims to investigate the development of N170 expertise for written words in Chinese dyslexic children of 7 to 10 years. And further, this project will examine how a kindergarten (5 to 6 years) student's N170 response to written words predicts their subsequent reading ability in the first and second grades, together with other typical behavioral predictions from kindergarten. As a benchmark to our predictions based on both N170 and typical behavioral measures, we will contrast this model against prediction based on behavioral measures alone. This project will not only systematically evaluate the potential of N170 as a biological marker for early diagnosis of Chinese children with DD; but also provide new evidence for a deep understanding the cognitive and neural mechanism of the disability of learning to read in dyslexic especially Chinese children.

发展性阅读障碍（Developmental Dyslexia, DD）是一种最常见的儿童青少年学习障碍，严重阻碍个体的发展，给家庭、社会和国家带来沉重压力。早期诊断和干预对DD的矫治至关重要，但迄今仍未找到可靠的早期生物学诊断指标。本项目拟从学习阅读障碍这个DD最核心的问题切入，以近期研究及本课题组对成人和儿童（特别是学前儿童）系列研究发现的左半球N170的选择性这个测量书面文字加工专家化的可靠电生理指标为基础，提出以N170作为汉语DD早期生物学诊断指标的假设，采用聚合交叉研究设计，系统考察7-10岁汉语DD儿童书面文字加工N170的发展特点及发展进程，检验学前5-6岁记录的N170反应对儿童阅读发展和阅读障碍的早期预测作用。本项目不仅可以系统评估N170可以作为一个DD早期诊断生物学标志的潜力，而且将为深入理解DD（特别是汉语DD）学习阅读困难的认知神经机制提供新的证据。

发展性阅读障碍（以下简称DD）是一种最常见的儿童和青少年学习障碍（患病率高达5-10%）。早期诊断和干预对DD的矫治至关重要，但迄今尚未找到客观可靠的生物学诊断指标。本项目以测量书面文字加工专家化的可靠电生理指标（即左半球文字N170选择性）为基础，采用横断与纵向相结合的研究设计，系统考察了不同年龄的汉语DD儿童书面文字加工N170反应的发展特点及发展进程，进一步检验了该指标对儿童后期阅读发展水平的预测作用。本项目采集了140余名正常和DD儿童的诱发脑电数据以及阅读相关的认知加工能力数据。该项目发现（1）N170脑电成分具有的文字选择性缺失是汉语DD儿童阅读学习困难的重要神经生理标志。随阅读经验的增长，正常儿童逐渐形成对文字有选择性的N170反应，而DD儿童并没有表现出文字选择性N170反应且这一缺失难以被代偿。（2）文字选择性N170脑电标记对儿童后期的阅读发展水平有独特的预测作用。纵向追踪研究发现，文字选择性N170脑电成分（特别是左半球伪字与非字诱发的N170波幅的差值）对儿童后期的阅读发展水平有显著的预测作用。在控制早期识字量和认知发展水平等因素的条件下，该预测作用仍然统计显著。本项目的发现不仅为建立汉语DD早期诊断的生物学标记提供了重要的实验证据，且进一步提出了更深刻的科学问题（文字选择性N170的形成机制），这对我们更深入地理解阅读发展与阅读障碍的神经机制有重要意义。