Department of Neurosciences, Research Group Experimental ORL, KU Leuven - University of Leuven, Leuven, Belgium.
Parenting and Special Education Research Unit, Faculty of Psychology and Educational Sciences, KU Leuven - University of Leuven, Leuven, Belgium.
Dev Sci. 2020 Nov;23(6):e12945. doi: 10.1111/desc.12945. Epub 2020 Apr 23.
Auditory processing of temporal information in speech is sustained by synchronized firing of neurons along the entire auditory pathway. In school-aged children and adults with dyslexia, neural synchronization deficits have been found at cortical levels of the auditory system, however, these deficits do not appear to be present in pre-reading children. An alternative role for subcortical synchronization in reading development and dyslexia has been suggested, but remains debated. By means of a longitudinal study, we assessed cognitive reading-related skills and subcortical auditory steady-state responses (80 Hz ASSRs) in a group of children before formal reading instruction (pre-reading), after 1 year of formal reading instruction (beginning reading), and after 3 years of formal reading instruction (more advanced reading). Children were retrospectively classified into three groups based on family risk and literacy achievement: typically developing children without a family risk for dyslexia, typically developing children with a family risk for dyslexia, and children who developed dyslexia. Our results reveal that children who developed dyslexia demonstrate decreased 80 Hz ASSRs at the pre-reading stage. This effect is no longer present after the onset of reading instruction, due to an atypical developmental increase in 80 Hz ASSRs between the pre-reading and the beginning reading stage. A forward stepwise logistic regression analysis showed that literacy achievement was predictable with an accuracy of 90.4% based on a model including three significant predictors, that is, family risk for dyslexia (R = .31), phonological awareness (R = .23), and 80 Hz ASSRs (R = .26). Given that (1) abnormalities in subcortical ASSRs preceded reading acquisition in children who developed dyslexia and (2) subcortical ASSRs contributed to the prediction of literacy achievement, subcortical auditory synchronization deficits may constitute a pre-reading risk factor in the emergence of dyslexia.
言语中时间信息的听觉加工是通过整个听觉通路中神经元的同步放电来维持的。在学龄期患有阅读障碍的儿童和成年人中，已经在听觉系统的皮质水平上发现了神经同步缺陷，然而，在阅读前的儿童中似乎没有发现这些缺陷。有人提出，皮质下同步在阅读发展和阅读障碍中可能起到替代作用，但这一观点仍存在争议。通过一项纵向研究，我们评估了一组儿童在接受正式阅读教学（阅读前）、接受 1 年正式阅读教学（开始阅读）和接受 3 年正式阅读教学（更高级阅读）前后的认知阅读相关技能和皮质下听觉稳态反应（80Hz ASSR）。根据家族性阅读障碍风险和读写能力的高低，我们将儿童分为三组：无家族性阅读障碍风险的正常发育儿童、有家族性阅读障碍风险的正常发育儿童和发展为阅读障碍的儿童。我们的研究结果表明，发展为阅读障碍的儿童在阅读前阶段表现出 80Hz ASSR 降低。这种效应在开始阅读教学后不再存在，因为在阅读前阶段和开始阅读阶段之间，80Hz ASSR 出现了异常的发育性增加。向前逐步逻辑回归分析显示，基于包括三个显著预测因子的模型，即阅读障碍的家族风险（R=0.31）、语音意识（R=0.23）和 80Hz ASSR（R=0.26），读写能力可以达到 90.4%的准确率进行预测。鉴于（1）在发展为阅读障碍的儿童中，皮质下 ASSR 的异常先于阅读能力的获得，以及（2）皮质下 ASSR 有助于预测读写能力，皮质下听觉同步缺陷可能构成阅读障碍发生的阅读前风险因素。
