EEG Characterization of Subgroups of Children with Learning Disorders

Our objective was to determine if there were subgroups within a group of scholars with not otherwise specified learning disorders and if they had specific electroencephalographic patterns. Eighty-five subjects (31 female, 8-11 years) who scored low in at least two subscales -reading, writing and arithmetic- of the Infant Neuropsychological Evaluation were included. Electroencephalograms were recorded in 19 leads during rest with eyes closed; absolute power was obtained every 0.39 Hz. Three subgroups were formed according to children’s performance: Group 1 (G1, higher scores than Group 2 in reading speed and reading and writing accuracy), Group 2 (G2, better performance than G1 in composition) and Group 3 (G3, lower scores than Groups 1 and 2 in the three subscales). G3 had higher absolute power in frequencies in the delta and theta range at left frontotemporal sites than G1 and G2. G2 had higher absolute power within alpha frequencies than G3 and G1 at the left occipital site. G3 had higher absolute power in frequencies in the beta range than G1 in parietotemporal areas and than G2 in left frontopolar and temporal sites. G1 had higher absolute power within beta frequencies than G2 in the left frontopolar site. G3 had lower gamma absolute power values than the other groups in the left hemisphere, and gamma activity was higher in G1 than in G2 in frontopolar and temporal areas. This group of children with learning disorders is very heterogeneous. Three subgroups were found with different cognitive profiles, as well as a different electroencephalographic pattern. It is important to consider these differences when planning interventions for children with learning disorders.

本研究旨在探究未特指型学习障碍（learning disorders）儿童群体中是否存在亚组，以及各亚组是否具有特异性脑电图（Electroencephalogram, EEG）模式。
本研究纳入85名受试儿童（31名女性，年龄8~11岁），这些儿童在《婴儿神经心理评估量表（Infant Neuropsychological Evaluation）》的阅读、书写与算数分量表中至少两项得分偏低。
采用闭眼静息状态下的19导电极采集脑电图信号，并以0.39Hz为频率间隔提取各频段绝对功率（absolute power）。
根据受试儿童的认知表现将其划分为3个亚组：第1亚组（G1：在阅读速度、阅读与书写准确率上的得分高于第2亚组G2）；第2亚组（G2：在写作能力维度上表现优于G1）；第3亚组（G3：在上述三个分量表中的得分均低于G1与G2）。
G3在左侧额颞区的δ波（delta）与θ波（theta）频段绝对功率显著高于G1与G2；G2在左侧枕区的α波（alpha）频段绝对功率显著高于G3与G1。
G3在顶颞区的β波（beta）频段绝对功率高于G1，在左侧额极区与颞区的β波频段绝对功率高于G2；G1在左侧额极区的β波频段绝对功率高于G2。
G3在左侧半球的γ波（gamma）绝对功率值低于其余两个亚组；在额极与颞区，G1的γ波活动水平高于G2。
该学习障碍儿童群体具有显著异质性。本研究共识别出3个亚组，各亚组不仅具备独特的认知特征，同时也存在特异性脑电图模式。在为学习障碍儿童制定干预方案时，需充分考虑上述群体与亚组间的差异。