Brandeis D, Vitacco D, Steinhausen H C
Department of Child and Adolescent Psychiatry, University of Zürich, Switzerland.
Acta Paedopsychiatr. 1994;56(3):239-47.
An important issue in current research on dyslexia is to what extent the reading deficits of dyslexic children are related to processing deficits at the sensory-visual level, at the cognitive-linguistic level or at both levels. Event-related potential mapping distinguishes the split-second processing stages during reading as brief brain-electric micro-states and can address this issue directly. Previously, conventional studies have yielded inconsistent patterns of event-related potential differences between dyslexic and control children, but most of these discrepancies could result from the widely differing methodologies. We used event-related potential mapping during silent reading of correct and incorrect sentence endings to examine the neurophysiology of sensory and cognitive processes in dyslexic and control children (n = 12/group). Selected findings from spatio-temporal analyses of map strength (global field power), map latency and map topography measured in three dimensions are presented. Both sensory-visual processes in a P110 micro-state and cognitive-linguistic processes in an early N400 micro-state were affected in dyslexic children, and processing delays, as well as qualitatively different patterns of neural activation, were found. Our findings also indicated that the use of specific cognitive tasks and of appropriate spatio-temporal analyses of event-related map series are critical factors for successful identification of specific processing deficits in brain mapping studies.
当前阅读障碍研究中的一个重要问题是，阅读障碍儿童的阅读缺陷在多大程度上与感觉视觉层面、认知语言层面或这两个层面的加工缺陷有关。事件相关电位图谱将阅读过程中的瞬间加工阶段区分为短暂的脑电微状态，从而能够直接解决这个问题。此前，传统研究在阅读障碍儿童与对照儿童之间得出了不一致的事件相关电位差异模式，但这些差异大多可能是由于研究方法差异巨大所致。我们在默读正确和错误的句子结尾时使用事件相关电位图谱，以研究阅读障碍儿童和对照儿童（每组12名）感觉和认知过程的神经生理学。本文展示了从在三个维度上测量的图谱强度（全局场功率）、图谱潜伏期和图谱地形的时空分析中得出的部分研究结果。阅读障碍儿童在P110微状态下的感觉视觉过程和早期N400微状态下的认知语言过程均受到影响，并且发现了加工延迟以及神经激活的质性不同模式。我们的研究结果还表明，在脑图谱研究中，使用特定的认知任务以及对事件相关图谱系列进行适当的时空分析是成功识别特定加工缺陷的关键因素。
