Visual processing deficits have been widely reported in developmental dyslexia however the locus of cognitive dysfunction remains unclear. Here, we examined the neural correlates of perceptual decision-making using a dot-motion task and electroencephalography (EEG) and investigated whether presenting deficits were unique to children with dyslexia or if they were also evident in other, typically developing children with equally immature reading systems. Sixty-eight children participated: 32 with dyslexia (DD; 16 females); 21 age-matched controls (AM; 11 females) and 15 reading-matched controls (RM; 9 females). All participants completed a bilaterally presented random-dot-motion task while EEG was recorded. Neural signatures of low level sensory processing (steady state visual evoked potentials; SSVEPs), pre-target attentional bias (posterior α power), attentional orienting (N2), evidence accumulation (centro-parietal positive decision signal; CPP) and execution of a motor response (β) were obtained to dissect the temporal sequence of perceptual decision-making. Reading profile provided a score of relative lexical and sublexical skills for each participant. Although all groups performed comparably in terms of task accuracy and false alarm rate, the DD group were slower and demonstrated an earlier peak latency, reduced slope and lower amplitude of the CPP compared with both AM and RM controls. Reading profile was found to moderate the relationship between word reading ability, reaction time as well as CPP indices showing that lexical dyslexics responded more slowly and had a shallower slope, reduced amplitude and earlier latency of CPP waveforms than sublexical dyslexics. These findings suggest that children with dyslexia, particularly those with relatively poorer lexical abilities, have a reduced rate and peak of evidence accumulation as denoted by CPP markers yet remain slow in their overt response. This is in keeping with hypotheses that children with dyslexia have impairment in effectively sampling and processing evidence about visual motion stimuli.

视觉处理缺陷已在发育性阅读障碍中得到广泛报道，但认知功能障碍的根源仍不清楚。在这里，我们使用点运动任务和脑电图 (EEG) 检查了知觉决策的神经相关性，并研究了呈现缺陷是否是患有阅读障碍的儿童所独有的，或者它们是否在其他阅读能力同样不成熟的典型发育儿童中也很明显系统。68 名儿童参加：32 名患有阅读障碍（DD；16 名女性）；21 个年龄匹配的对照（上午；11 名女性）和 15 个阅读匹配的对照（RM；9 名女性）。所有参与者在记录 EEG 的同时完成了双边呈现的随机点运动任务。低水平感觉处理的神经特征（稳态视觉诱发电位；SSVEPs），获得目标前注意偏差（后α功率）、注意定向（N2）、证据积累（中心顶叶正决策信号；CPP）和运动反应的执行（β），以剖析知觉决策的时间序列. 阅读资料为每个参与者提供了相对词汇和亚词汇技能的分数。尽管所有组在任务准确性和误报率方面的表现相当，但与 AM 和 RM 对照组相比，DD 组较慢，并表现出更早的峰值延迟、降低的斜率和较低的 CPP 幅度。研究发现阅读档案可以调节单词阅读能力、反应时间和 CPP 指数之间的关系，表明词汇阅读障碍者的反应更慢，斜率更小，与亚词汇阅读障碍者相比，CPP 波形的振幅降低且延迟时间更早。这些发现表明，有阅读障碍的儿童，尤其是那些词汇能力相对较差的儿童，证据积累的速度和峰值降低，如 CPP 标记所示，但他们的公开反应仍然缓慢。这与以下假设一致，即患有阅读障碍的儿童在有效采样和处理有关视觉运动刺激的证据方面存在障碍。