Dushanova Juliana A, Tsokov Stefan A
Institute of Neurobiology, Bulgarian Academy of Sciences, 23 Acad. G. Bonchev St., 1113, Sofia, Bulgaria.
J Integr Neurosci. 2020 Dec 30;19(4):601-618. doi: 10.31083/j.jin.2020.04.193.
Aberrations in functional connectivity in children with developmental dyslexia have been found in electroencephalographic studies using graph analysis. How training with visual tasks can modify the functional semantic network in developmental dyslexia remains unclear. We investigate local and global topological properties of functional networks in multiple EEG frequency ranges based on a small-world propensity method in controls, pre- and post-training dyslexic children during visual word/pseudoword processing. Results indicated that the EEG network topology in dyslexics before the training was more integrated than controls, and after training - more segregated and similar to that of the controls in the theta (θ: 4-8), alpha (α: 8-13), beta (β1: 13-20; β2: 20-30), and gamma (γ1: 30-48; γ2: 52-70 Hz) bands for three graph measures. The pre-training dyslexics exhibited a reduced strength and betweenness centrality of the left anterior temporal and parietal regions in the θ, α, β1 and γ1-frequency bands, compared to the controls. The simultaneous appearance of hubs in the left hemisphere (or both hemispheres) at temporal and parietal (α-word/γ-pseudoword discrimination), temporal and middle frontal cortex (θ, α-word), parietal and middle frontal cortex (β1-word), parietal and occipitotemporal cortices (θ-pseudoword), identified in the EEG-based functional networks of normally developing children were not present in the networks of dyslexics. The hub distribution for dyslexics in the θ, α, and β1 bands became similar to that of the controls. The topological organization of functional networks and the less efficient network configuration (long characteristic path length) in dyslexics compared to the more optimal global organization in the controls was studied for the first time after remediation training.
在使用图形分析的脑电图研究中，已发现发育性阅读障碍儿童存在功能连接异常。然而，视觉任务训练如何改变发育性阅读障碍中的功能语义网络仍不清楚。我们基于小世界倾向方法，研究了对照组、训练前和训练后的阅读障碍儿童在视觉单词/假词处理过程中多个脑电频率范围内功能网络的局部和全局拓扑特性。结果表明，训练前阅读障碍儿童的脑电网络拓扑比对照组更具整合性，训练后则更具分离性，并且在θ（4-8Hz）、α（8-13Hz）、β1（13-20Hz）、β2（20-30Hz）和γ1（30-48Hz）、γ2（52-70Hz）频段的三种图形测量指标上与对照组相似。与对照组相比，训练前的阅读障碍儿童在θ、α、β1和γ1频段的左前颞叶和顶叶区域的强度和中介中心性降低。在正常发育儿童基于脑电图的功能网络中，在颞叶和顶叶（α-单词/γ-假词辨别）、颞叶和额中回（θ、α-单词）、顶叶和额中回（β1-单词）、顶叶和枕颞叶皮质（θ-假词）的左半球（或双侧半球）同时出现的枢纽，在阅读障碍儿童的网络中不存在。阅读障碍儿童在θ、α和β1频段的枢纽分布变得与对照组相似。首次在矫正训练后研究了阅读障碍儿童与对照组更优化的全局组织相比，功能网络的拓扑组织和效率较低的网络配置（长特征路径长度）。
