Cognition and Development Lab, Catholic University of Louvain, Louvain-La-Neuve, Belgium.
Cortex. 2010 Jun;46(6):717-38. doi: 10.1016/j.cortex.2009.11.002. Epub 2010 Jan 6.
While there is growing evidence that some dyslexic children suffer from a deficit in simultaneously processing multiple visually displayed elements, the precise nature of the deficit remains largely unclear. The aim of the present study is to investigate possible cognitive impairments at the source of this deficit in dyslexic children. The visual processing of simultaneously presented letters was thus thoroughly assessed in two dyslexic children by means of a task that requires the report of briefly presented multi-letters arrays. A computational model of the attentional involvement in multi-object recognition (Bundesen, 1990, 1998) served as framework for analysing the data. By combining psychophysical measurements with computational modelling, we demonstrated that the visual processing deficit of simultaneously displayed letters, observed in the two dyslexic individuals reported in the current study, stems from at least two distinct cognitive sources: a reduction of the rate of-letter-information uptake, and a limitation of the maximal number of elements extracted from a brief visual display and stored in visual short-term memory. Possible relations between these impairments and learning to read proficiently are discussed.
虽然越来越多的证据表明，一些诵读困难的儿童在同时处理多个视觉显示元素方面存在缺陷，但这种缺陷的确切性质在很大程度上仍不清楚。本研究的目的是探究诵读困难儿童这种缺陷的根源可能存在的认知障碍。通过一项需要报告短暂呈现的多字母数组的任务，对两名诵读困难儿童的同时呈现字母的视觉处理进行了彻底评估。注意力在多目标识别中的计算模型（Bundesen，1990 年，1998 年）作为分析数据的框架。通过将心理物理学测量与计算建模相结合，我们证明了当前研究报告的两名诵读困难个体中观察到的同时呈现字母的视觉处理缺陷源于至少两个不同的认知来源：字母信息摄取率的降低，以及从短暂视觉显示中提取并存储在视觉短期记忆中的最大元素数量的限制。讨论了这些障碍与熟练阅读学习之间的可能关系。
