发展性阅读障碍的听觉时间加工缺陷

发展性阅读障碍是指个体在智力正常并且不缺乏学校教育的情况下, 仍无法获得与年龄相匹配的阅读技能的一种学习障碍, 其缺陷的本质一直是研究者争论的焦点。大量研究显示, 阅读障碍者常表现出听觉时间加工损伤。在行为层面, 阅读障碍者难以辨别快速、连续呈现刺激的顺序以及刺激本身的动态时间特征。在神经层面, 阅读障碍者诱发的失匹配负波更弱且具有异常的神经同步加工。这些损伤同时存在于对言语和非言语刺激的加工中, 表明听觉时间加工缺陷非言语加工所特有。未来的研究还需阐明以下几个问题：1)阅读障碍的听觉时间加工缺陷发生在哪些时间窗口, 随年龄增长如何变化; 2)阅读障碍听觉时间加工缺陷在神经层面的时间进程是怎样的; 3)听觉时间加工缺陷是否为阅读障碍的核心缺陷。

Auditory temporal processing deficits in developmental dyslexia

Developmental dyslexia is a neurological disorder characterized by a specific deficit in reading, despite adequate intelligence and socioeconomic opportunity. A large number of studies have revealed that dyslexics usually exhibit impaired auditory temporal processing. At the behavioral level, dyslexics struggle to discriminate the sequence of rapid and successive stimuli as well as dynamical temporal characteristics. At the neural level, dyslexics evoke weaker mismatch negativity (MMN) and have abnormal neural synchronization. These deficits have been found in the processing of both verbal and non-verbal stimuli, suggesting that such deficits are not specific to speech processing. However, the auditory temporal-order processing deficits of dyslexia are manifested in the processing of both rapidly and slowly presented auditory stimuli. Besides, dyslexic children have more abnormal neural synchronization in low-frequency temporal modulation, and dyslexic adults have more abnormal neural synchronization in high-frequency temporal modulation. Therefore, auditory temporal processing deficits of dyslexia seem to occur not only in a narrow temporal window, but also in a wider temporal window. The developmental characteristics of dyslexia may also imply that the temporal window of auditory temporal processing deficits will narrow with age. Moreover, only the neural mechanism of dyslexics while distinguishing deviant auditory temporal stimuli has been examined in previous studies, and there is still a lack of research, such as the neural mechanism of more general auditory temporal processing and the changing process of such a neural mechanism over time.