Žarić Gojko, Fraga González Gorka, Tijms Jurgen, van der Molen Maurits W, Blomert Leo, Bonte Milene
Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, University of Maastricht, Maastricht, Netherlands; Maastricht Brain Imaging Center (M-BIC), Maastricht, Netherlands.
Department of Psychology, University of Amsterdam, Amsterdam, Netherlands; Rudolf Berlin Center, Amsterdam, Netherlands.
PLoS One. 2014 Oct 16;9(10):e110337. doi: 10.1371/journal.pone.0110337. eCollection 2014.
The acquisition of letter-speech sound associations is one of the basic requirements for fluent reading acquisition and its failure may contribute to reading difficulties in developmental dyslexia. Here we investigated event-related potential (ERP) measures of letter-speech sound integration in 9-year-old typical and dyslexic readers and specifically test their relation to individual differences in reading fluency. We employed an audiovisual oddball paradigm in typical readers (n = 20), dysfluent (n = 18) and severely dysfluent (n = 18) dyslexic children. In one auditory and two audiovisual conditions the Dutch spoken vowels/a/and/o/were presented as standard and deviant stimuli. In audiovisual blocks, the letter 'a' was presented either simultaneously (AV0), or 200 ms before (AV200) vowel sound onset. Across the three children groups, vowel deviancy in auditory blocks elicited comparable mismatch negativity (MMN) and late negativity (LN) responses. In typical readers, both audiovisual conditions (AV0 and AV200) led to enhanced MMN and LN amplitudes. In both dyslexic groups, the audiovisual LN effects were mildly reduced. Most interestingly, individual differences in reading fluency were correlated with MMN latency in the AV0 condition. A further analysis revealed that this effect was driven by a short-lived MMN effect encompassing only the N1 window in severely dysfluent dyslexics versus a longer MMN effect encompassing both the N1 and P2 windows in the other two groups. Our results confirm and extend previous findings in dyslexic children by demonstrating a deficient pattern of letter-speech sound integration depending on the level of reading dysfluency. These findings underscore the importance of considering individual differences across the entire spectrum of reading skills in addition to group differences between typical and dyslexic readers.
字母与语音关联的习得是流畅阅读习得的基本要求之一，其缺失可能导致发展性阅读障碍中的阅读困难。在此，我们研究了9岁正常阅读者和阅读障碍者字母与语音整合的事件相关电位（ERP）指标，并特别测试了它们与阅读流畅性个体差异的关系。我们对正常阅读者（n = 20）、阅读不流畅（n = 18）和严重阅读不流畅（n = 18）的阅读障碍儿童采用了视听Oddball范式。在一种听觉条件和两种视听条件下，荷兰语中的元音/a/和/o/被呈现为标准刺激和偏差刺激。在视听组块中，字母“a”要么在元音发音开始时同时呈现（AV0），要么在元音发音开始前200毫秒呈现（AV200）。在这三组儿童中，听觉组块中的元音偏差引发了相当的失匹配负波（MMN）和晚期负波（LN）反应。在正常阅读者中，两种视听条件（AV0和AV200）都导致MMN和LN波幅增强。在两个阅读障碍组中，视听LN效应略有降低。最有趣的是，阅读流畅性的个体差异与AV0条件下的MMN潜伏期相关。进一步分析表明，这种效应是由严重阅读不流畅的阅读障碍者中仅包含N1窗口的短暂MMN效应驱动的，而在其他两组中则是包含N1和P2窗口的较长MMN效应。我们的结果通过证明依赖于阅读不流畅程度的字母与语音整合模式缺陷，证实并扩展了先前对阅读障碍儿童的研究结果。这些发现强调了除了正常阅读者和阅读障碍者之间的组间差异外，考虑整个阅读技能范围内个体差异的重要性。
