KU Leuven - University of Leuven, Department of Neurosciences, Research Group Experimental ORL, Leuven, Belgium; KU Leuven - University of Leuven, Faculty of Psychology and Education Sciences, Parenting and Special Education Research Unit, Leuven, Belgium.
KU Leuven - University of Leuven, Faculty of Psychology and Education Sciences, Parenting and Special Education Research Unit, Leuven, Belgium.
Cortex. 2019 Apr;113:128-140. doi: 10.1016/j.cortex.2018.12.006. Epub 2018 Dec 21.
In recent studies phonological deficits in dyslexia are related to a deficit in the synchronization of neural oscillations to the dynamics of the speech envelope. The temporal features of both amplitude modulations and rise times characterize the speech envelope. Previous studies uncovered the inefficiency of the dyslexic brain to follow different amplitude modulations in speech. However, it remains to be investigated how the envelope's rise time mediates this neural processing. In this study we examined neural synchronization in students with and without dyslexia using auditory steady-state responses at theta, alpha, beta and low-gamma range oscillations (i.e., 4, 10, 20 and 40 Hz) to stimuli with different envelope rise times. Our results revealed reduced neural synchronization in the alpha, beta and low-gamma frequency ranges in dyslexia. Moreover, atypical neural synchronization was modulated by rise time for alpha and beta oscillations, showing that deficits found at 10 and 20 Hz were only evident when the envelope's rise time was significantly shortened. This impaired tracking of rise time cues may very well lead to the speech and phonological processing difficulties observed in dyslexia.
在最近的研究中，阅读障碍者的语音缺陷与神经振荡对语音包络动态的同步失调有关。幅度调制和上升时间的时间特征都可以描述语音包络。以前的研究揭示了阅读障碍者大脑在跟随语音中不同幅度调制时效率低下。然而，目前尚不清楚包络的上升时间如何调节这种神经处理。在这项研究中，我们使用听觉稳态反应（theta、alpha、beta 和低 gamma 范围的振荡，即 4、10、20 和 40 Hz），检查了有和没有阅读障碍的学生对不同上升时间刺激的神经同步。我们的结果显示，阅读障碍者在 alpha、beta 和低 gamma 频率范围内的神经同步性降低。此外，alpha 和 beta 振荡的异常神经同步性受上升时间的调节，表明在 10 和 20 Hz 时发现的缺陷仅在包络的上升时间明显缩短时才明显。这种对上升时间线索的跟踪障碍可能导致阅读障碍者观察到的语音和语音处理困难。
