Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience & Maastricht Brain Imaging Institute (M-BIC), Maastricht University, The Netherlands.
Dev Sci. 2011 Jul;14(4):635-48. doi: 10.1111/j.1467-7687.2010.01007.x. Epub 2010 Dec 5.
The phonological deficit theory of dyslexia assumes that degraded speech sound representations might hamper the acquisition of stable letter-speech sound associations necessary for learning to read. However, there is only scarce and mainly indirect evidence for this assumed letter-speech sound association problem. The present study aimed at clarifying the nature and the role of letter-speech sound association problems in dyslexia by analysing event-related potentials (ERP) of 11-year-old dyslexic children to speech sounds in isolation or combined with letters, which were presented either simultaneously with or 200 ms before the speech sounds. Recent studies with normal readers revealed that letters systematically modulated speech sound processing in an early (mismatch negativity or MMN) and late (Late Discriminatory Negativity or LDN) time-window. The amplitude of the MMN and LDN to speech sounds was enhanced when speech sounds were presented with letters. The dyslexic readers in the present study, however, did not exhibit any early influences of letters on speech sounds even after 4 years of reading instruction, indicating no automatic integration of letters and speech sounds. Interestingly, they revealed a systematic late effect of letters on speech sound processing, probably reflecting the mere association of letters and speech sounds. This pattern is strongly divergent from that observed in age-matched normal readers, who showed both early and late effects, but reminiscent of that observed in beginner normal readers in a previous study (Froyen, Bonte, van Atteveldt & Blomert, 2009). The finding that the quality of letter-speech sound processing is directly related to reading fluency urges further research into the role of audiovisual integration in the development of reading failure in dyslexia.
阅读障碍的语音缺陷理论假设，语音表示的退化可能会阻碍学习阅读所需的稳定字母-语音关联的获得。然而，这种假设的字母-语音关联问题只有很少且主要是间接的证据。本研究旨在通过分析 11 岁阅读障碍儿童对孤立的语音或与字母组合的语音的事件相关电位（ERP），来阐明阅读障碍中字母-语音关联问题的性质和作用，这些语音分别与语音同时呈现或在语音之前 200 毫秒呈现。最近对正常读者的研究表明，字母在早期（错配负波或 MMN）和晚期（晚期辨别负波或 LDN）时间窗口中系统地调节语音处理。当语音与字母一起呈现时，MMN 和 LDN 对语音的振幅增强。然而，本研究中的阅读障碍读者即使在经过 4 年的阅读教学后，也没有表现出任何早期字母对语音的影响，表明字母和语音没有自动整合。有趣的是，他们显示出字母对语音处理的系统的晚期影响，可能反映了字母和语音的简单关联。这种模式与年龄匹配的正常读者观察到的模式明显不同，正常读者观察到了早期和晚期的影响，但与之前一项研究中初级正常读者观察到的模式相似（Froyen、Bonte、van Atteveldt 和 Blomert，2009）。字母-语音处理质量与阅读流畅度直接相关的发现，促使我们进一步研究视听整合在阅读障碍发展中阅读失败中的作用。
