汉语阅读障碍儿童行为及脑机制的多模态研究

It is very uncontroversial that in alphabetic writing systems like English, the spaces between words facilitate reading. Unlike English, Chinese do not include spaces between words, the text is formed by strings of equally spaced symbols called characters. Chinese readers do not know clearly about which characters do actually comprise a word. However, in order to recognize a word, the primary task for a Chinese reader is to segment words correctly during reading. Some studies have showed that word spaces facilitated Chinese reading for children, adults and second language learners when reading Chinese as their second language. During normal Chinese reading, even though there is no word space, skilled readers can use high-level linguistic segmentation cues, such as the probability of being a single character word, character's positional probability and the familiarity of constituents. However, about 5-10% of the school children in Chinese are dyslexic children, who have deficits of word segmentation but have been neglected in the domain of clinic. The present project will firstly check in the level of dyslexic childre's word segmentation deficit using eye tracking. Secondly, we will combine eye tracking and near infrared reflectance spectroscopy (fNIRS) to investigate the behavioral and brain mechanisms of dyslexic children's word segmentations. Finally, we will examine the validity of word segmentation using as an indicator to detect dyslexic children by functional magnetic resonance imaging (fMRI). Meanwhile, we will explore how the reading proficiency of dyslexic children will be improved after trainning.

用汉字书写的文本，会因词切分的不同而产生意义上很大差异。如"武汉市长江大桥"可切分为"武汉 市长 江大桥"和"武汉市 长江 大桥"。因此，汉语阅读的首要任务是读者正确进行词切分。用空格作为词切分线索研究发现，在汉语文本中加入空格能促进外国留学生、儿童和成人的阅读。熟练的汉语读者能利用成词概率、词素位置概率和词素熟悉性等语言线索进行词切分。在我国阅读障碍儿童占学龄儿童总数的5-10%，他们在阅读过程中存在词切分缺陷但很少被临床所关注。本项目首先用眼动记录技术查明阅读障碍儿童利用哪种语言线索存在缺陷；其次将眼动记录技术与功能近红外光学成像技术结合，探讨阅读障碍儿童存在缺陷的认知及脑机制；最后用功能核磁共振技术检测词切分作为诊断阅读障碍儿童指标的有效性，同时通过词切分的强化训练，考察阅读障碍儿童在训练前后阅读能力改善的情况以及相应脑区激活的变化。

本项目采用多种测量工具和技术，以汉语阅读障碍儿童、年龄及能力匹配组儿童、成人大学生和老年人为研究对象，从七个方面探讨汉语阅读障碍儿童阅读中的眼动模式以及汉语阅读的脑机制：（1）汉语发展性阅读障碍的词切分；（2）汉语发展性阅读障碍字词识别的特点；（3）阅读障碍的视觉拥挤效应；（4）阅读障碍的快速命名及其认知机制；（5）汉语发展性阅读障碍儿童的新词学习及其改善；（6）汉语阅读的副中央凹加工；（7）汉语阅读中眼动控制的影响因素。在一系列研究的基础上，我们明确了插入词间空格可有效改善汉语阅读障碍儿童朗读的效率；汉语阅读障碍儿童对形声字声旁线索的利用能力存在滞后和缺陷；适当扩大字间距、降低视觉复杂性、调大字号可改善其视觉拥挤；汉语阅读障碍儿童在快速命名任务中，副中央凹加工能力低于控制组儿童，并且其预视效益小于正常儿童；词间空格可改善汉语阅读障碍儿童新词学习过程中的阅读效率；视觉因素，如词间空格、字号、词长等，高水平语言学因素，如词频、结构等，以及发展中的个体差异，如阅读水平，均会影响汉语阅读中的眼动控制。以上研究成果不仅加深了研究者对汉语阅读障碍儿童行为及脑机制的理解，还为提高汉语阅读障碍儿童的阅读效率提供强有力的科学依据和重要启示，有助于汉语阅读障碍儿童从“学会阅读”成功过渡到“从阅读中学习”。在本项目资助下，相关研究成果以学术论文的形式共发表30篇，其中7篇发表在Journal of Experimental Psychology: Human Perception and Performance等SCI/SSCI期刊上，22篇发表在《心理学报》、《心理科学》等中文核心期刊上。