The aim of this study was to compare neural network topology of 30 patients with first episode schizophrenia (FES) and 30 multiepisode schizophrenia (mean number of psychotic relapses =4 years, duration of illness >5 years) patients, who were assessed with graph theory methods. This comparison was designed to identify network differences, which might be assigned to the burden of a mental disease. To estimate functional connectivity, we applied the phase lag index algorithm and the minimum spanning tree (MST) for the characterization of network topology. Group comparison revealed significant between-group differences of maximal betweenness centrality and tree hierarchy in the beta-band and hierarchy in the gamma-band. MST results showed that in the beta-band the network of patients with longer duration of illness (LDI) was characterized by more centralized network, while subjects with short duration of illness (FES) showed more decentralized topology. Furthermore, in the gamma-band, our results suggest that illness duration can disturb the balance between overload prevention and large-scale integration in the brain network. A qualitative analysis proved that the topological displacement of hubs also differentiated the FES and LDI groups. Our findings suggest that the duration of illness significantly affects the topology of resting-state functional network, supporting the “disconnectivity hypothesis’ in schizophrenia.

中文翻译：

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两种不同疾病持续时间和疾病负担的基于脑电图的神经网络组织的定量和定性比较：应用最小生成树的图分析

本研究的目的是比较 30 名首发精神分裂症 (FES) 患者和 30 名多发性精神分裂症患者（精神病复发的平均次数 = 4 年，病程 > 5 年）的神经网络拓扑结构，这些患者通过图论进行评估方法。这种比较旨在识别可能与精神疾病负担有关的网络差异。为了估计功能连通性，我们应用相位滞后指数算法和最小生成树 (MST) 来表征网络拓扑。组间比较揭示了 β 波段中的最大介数中心性和树层次结构和 γ 波段中的层次结构的显着组间差异。MST 结果显示，在 beta 波段中，病程较长 (LDI) 患者网络的特点是网络更集中，而病程短 (FES) 的受试者则表现出更分散的拓扑结构。此外，在伽马波段，我们的结果表明，疾病持续时间会扰乱预防过载和大脑网络大规模整合之间的平衡。定性分析证明，枢纽的拓扑位移也区分了 FES 和 LDI 组。我们的研究结果表明，疾病的持续时间显着影响静息状态功能网络的拓扑结构，支持精神分裂症中的“断开连接假说”。我们的研究结果表明，疾病持续时间会扰乱预防过载和大脑网络大规模整合之间的平衡。定性分析证明，枢纽的拓扑位移也区分了 FES 和 LDI 组。我们的研究结果表明，疾病的持续时间显着影响静息状态功能网络的拓扑结构，支持精神分裂症中的“断开连接假说”。我们的研究结果表明，疾病持续时间会扰乱预防过载和大脑网络大规模整合之间的平衡。定性分析证明，枢纽的拓扑位移也区分了 FES 和 LDI 组。我们的研究结果表明，疾病的持续时间显着影响静息状态功能网络的拓扑结构，支持精神分裂症中的“断开连接假说”。