Rüsseler J, Gerth I, Heldmann M, Münte T F
Dept. of Psychology, University of Bamberg, Bamberg, Germany.
Dept. of Neurology, Klinikum Magdeburg, Magdeburg, Germany.
Neuroscience. 2015 Feb 26;287:55-65. doi: 10.1016/j.neuroscience.2014.12.023. Epub 2014 Dec 20.
The present study used event-related brain potentials (ERPs) to investigate audiovisual integration processes in the perception of natural speech in a group of German adult developmental dyslexic readers. Twelve dyslexic and twelve non-dyslexic adults viewed short videos of a male German speaker. Disyllabic German nouns served as stimulus material. The auditory and the visual stimulus streams were segregated to create four conditions: in the congruent condition, the spoken word and the auditory word were identical. In the incongruent condition, the auditory and the visual word (i.e., the lip movements of the utterance) were different. Furthermore, on half of the trials, white noise (45 dB SPL) was superimposed on the auditory trace. Subjects had to say aloud the word they understood after they viewed the video. Behavioral data. Dyslexic readers committed more errors compared to normal readers in the noise conditions, and this effect was particularly present for congruent trials. ERPs showed a distinct N170 component at temporo-parietal electrodes that was smaller in amplitude for dyslexic readers. Both, normal and dyslexic readers, showed a clear effect of noise at centro-parietal electrodes between 300 and 600 ms. An analysis of error trials reflecting audiovisual integration (verbal responses in the incongruent noise condition that are a mix of the visual and the auditory word) revealed more positive ERPs for dyslexic readers at temporo-parietal electrodes 200-500 ms poststimulus. For normal readers, no such effect was present. These findings are discussed as reflecting increased effort in dyslexics under circumstances of distorted acoustic input. The superimposition of noise leads dyslexics to rely more on the integration of auditory and visual input (lip reading). Furthermore, the smaller N170-amplitudes indicate deficits in the processing of moving faces in dyslexic adults.
本研究使用事件相关脑电位（ERP）来调查一组德国成年发展性阅读障碍读者在自然语音感知中的视听整合过程。12名阅读障碍者和12名非阅读障碍成年人观看了一名德国男性说话者的短视频。双音节德语名词作为刺激材料。听觉和视觉刺激流被分离以创建四种条件：在一致条件下，口语单词和听觉单词相同。在不一致条件下，听觉和视觉单词（即话语的唇动）不同。此外，在一半的试验中，白噪声（45 dB SPL）叠加在听觉信号上。受试者在观看视频后必须大声说出他们理解的单词。行为数据。在噪声条件下，阅读障碍读者比正常读者犯的错误更多，并且这种效应在一致试验中尤为明显。ERP显示在颞顶电极处有一个明显的N170成分，阅读障碍读者的该成分振幅较小。正常读者和阅读障碍读者在300至600毫秒之间的中央顶电极处都显示出明显的噪声效应。对反映视听整合的错误试验（不一致噪声条件下的言语反应，是视觉和听觉单词的混合）进行分析发现，阅读障碍读者在刺激后200 - 500毫秒时，颞顶电极处的ERP更正。对于正常读者，则没有这种效应。这些发现被认为反映了阅读障碍者在声学输入失真的情况下付出了更多努力。噪声的叠加导致阅读障碍者更多地依赖听觉和视觉输入的整合（唇读）。此外，较小的N170振幅表明阅读障碍成年人在处理动态面部方面存在缺陷。
