Granados Barbero Raúl, de Vos Astrid, Ghesquière Pol, Wouters Jan
Research Group Experimental ORL, Department of Neurosciences, 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.
Eur J Neurosci. 2021 Dec;54(11):7839-7859. doi: 10.1111/ejn.15515. Epub 2021 Nov 14.
Different studies have suggested that language and developmental disorders such as dyslexia are associated with a disturbance of auditory entrainment and of the functional hemispheric asymmetries during speech processing. These disorders typically result from an issue in the phonological component of language that causes problems to represent and manipulate the phonological structure of words at the syllable and/or phoneme level. We used Auditory Steady-State Responses (ASSRs) in EEG recordings to investigate the brain activation and hemisphere asymmetry of theta, alpha, beta and low-gamma range oscillations in typical readers and readers with dyslexia. The aim was to analyse whether the group differences found in previous electrode level studies were caused by a different source activation pattern or conversely was an effect that could be found on the active brain sources. We could not find differences in the brain locations of the main active brain sources. However, we observed differences in the extracted waveforms. The group average of the first DSS component of all signal-to-noise ratios of ASSR at source level was higher than the group averages at the electrode level. These analyses included a lower alpha synchronisation in adolescents with dyslexia and the possibility of compensatory mechanisms in theta, beta and low-gamma frequency bands. The main brain auditory sources were located in cortical regions around the auditory cortex. Thus, the differences observed in auditory EEG experiments would, according to our findings, have their origin in the intrinsic oscillatory mechanisms of the brain cortical sources related to speech perception.
不同的研究表明，语言和发育障碍（如诵读困难）与言语处理过程中听觉同步以及功能性半球不对称的紊乱有关。这些障碍通常源于语言的语音成分问题，导致在音节和/或音素层面表征和操作单词的语音结构时出现问题。我们在脑电图记录中使用听觉稳态反应（ASSR）来研究典型阅读者和诵读困难阅读者大脑中θ、α、β和低γ频段振荡的激活情况以及半球不对称性。目的是分析之前在电极层面研究中发现的组间差异是由不同的源激活模式引起的，还是相反，是在活跃脑源上可以发现的一种效应。我们没有发现主要活跃脑源的脑区位置存在差异。然而，我们观察到提取的波形存在差异。源层面所有ASSR信噪比的第一个DSS成分的组平均值高于电极层面的组平均值。这些分析包括诵读困难青少年中较低的α同步性以及θ、β和低γ频段存在补偿机制的可能性。主要的脑听觉源位于听觉皮层周围的皮质区域。因此，根据我们的研究结果，在听觉脑电图实验中观察到的差异源于与言语感知相关的大脑皮质源的内在振荡机制。
