Rüsseler Jascha, Kowalczuk Justyna, Johannes Sönke, Wieringa Berdieke M, Münte Thomas F
Department of Neuropsychology, Otto-von-Guericke University, Magdeburg, Germany.
Dyslexia. 2002 Jul-Sep;8(3):125-42. doi: 10.1002/dys.221.
Event-related brain potentials were recorded in two three-stimulus oddball tasks in 13 adult dyslexic and 13 age- and IQ-matched normal readers. The stimuli consisted of a random series of frequent (80%) and non-frequent tones (10%) as well as occasionally inserted novel sounds (10%). The experiment comprised an active (response to the rare target tone) and a passive listening condition. No performance differences were found for dyslexic and normal readers in the active task. In both conditions, novel sounds evoked a centrally distributed P3a-component followed by a P3b-component most prominent at parietal electrodes for target and novel sounds. Additionally, a slow negativity emerged after presentation of novel sounds at frontal electrodes. In the active condition only, peak amplitude of the P3a and the frontal slow negativity to novel stimuli were slightly enlarged for dyslexic readers. These findings indicate a larger distractability of dyslexic readers (enhancement of P3a to novel tones). Furthermore, we propose that dyslexics need to employ more cognitive resources to refocus on the task at hand (as indicated by the enlarged slow frontal negativity).
在两项三刺激Oddball任务中，对13名成年阅读障碍者以及13名年龄和智商匹配的正常阅读者记录了事件相关脑电位。刺激由一系列随机的频繁（80%）和不频繁的音调（10%）以及偶尔插入的新声音（10%）组成。实验包括一个主动（对罕见目标音调做出反应）和一个被动聆听条件。在主动任务中，阅读障碍者和正常阅读者未发现表现差异。在两种条件下，新声音都会诱发一个中央分布的P3a成分，随后是一个在顶叶电极对目标和新声音最为突出的P3b成分。此外，在额叶电极呈现新声音后会出现一个缓慢的负电位。仅在主动条件下，阅读障碍者对新刺激的P3a峰值幅度和额叶缓慢负电位略有增大。这些发现表明阅读障碍者的注意力分散性更大（P3a对新音调增强）。此外，我们提出阅读障碍者需要动用更多认知资源来重新专注于手头任务（如额叶缓慢负电位增大所示）。
