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在Lennox-Gastaut(LG)综合征的患者中,持续反复的癫痫活动被认为是导致认知损害的原因(癫痫脑病)。使用同步脑电图-功能磁共振(EEG-fMRI)的影像手段,发现在LG综合征中癫痫放电会涉及大量在正常情况下与认知重要过程相关的网络。因此在LG综合征中,癫痫活动与认知网络相关,患者出现广泛的认知损害。就此提出假设,LG综合征认知网络间的相互作用存在持续异常。使用无任务EEG-fMRI研究了15例LG综合征患者(28.7±10.6岁)和17名健康对照者(27.6±6.6岁)。使用组独立成分分析(Group level independent components analysis,ICA),选定4个网络用于观察(默认模式、背侧注意、执行控制及前显著网络)。对每一研究个体都进行网络内和网络间的功能连接分析后,再对比LG综合征患者和健康对照组的网络行为。为了证明在头皮未检测到放电行为时两组之间仍存在差别(即差别是持续存在的),用足够数据对6例患者进行了放电相关和放电非相关时段的分别分析。在LG综合征中,认知网络特点为:①网络内部整合性减少,包括在默认模式的网络中联系更弱;②网络之间的分离程度减低,包括默认模式和背侧注意网络间更强烈的连接。不论是否有头皮EEG的放电,fMRI上的异常相互作用均存在,表明在没有头皮能检测到的癫痫活动时也可能有异常网络行为的存在。在LG综合征中,认知网络之间相互作用关系是持续异常的。根据临床中LG综合征典型性地出现发病后认知下降,并且在癫痫得到控制后认知可能会有一定改善,该研究结果与提出的假说一致,表明LG综合征的癫痫过程可能导致并且使异常的网络行为延续。癫痫脑病的发生也许是持续存在的认知网络之间相互作用异常所导致的。
In patients with Lennox-Gastaut (LG) syndrome, persistent recurrent seizure activity is considered the cause of cognitive impairment (epileptic encephalopathy). Using EEG-fMRI imaging, it was found that epileptiform discharges in LG syndrome involve a large number of networks that are normally associated with cognitively important processes. Therefore, in LG syndrome, epilepsy activity is associated with cognitive networks and patients have extensive cognitive impairment. In this connection, we hypothesize that the interaction between cognitive networks in LG syndrome persists. Fifteen patients with LG syndrome (28.7 ± 10.6 years) and 17 healthy controls (27.6 ± 6.6 years) were studied using the task-free EEG-fMRI. Using Group level independent components analysis (ICA), 4 networks were selected for observation (default mode, dorsal attention, executive control, and pre-eminent network). After analyzing the intra-network and intra-network functional connections for each study individual, the network behavior of patients with LG syndrome and healthy controls was compared. To demonstrate that there was still a difference between the two groups when scalp discharge was undetectable (ie, the difference persisted), six patients were analyzed individually for discharge-related and non-discharge-related periods of discharge with sufficient data. In LG syndrome, cognitive networks are characterized by: (1) a reduction in intra-network integration, including a weaker link in the default-mode network; (2) a reduction in the degree of separation between networks, including the default mode and the dorsal side, Connection. Irrespective of whether there is a scalp EEG discharge or not, there is an abnormal interaction on the fMRI, indicating that there may be abnormal network behavior even in the absence of epileptic activity detectable by the scalp. In LG syndrome, the interaction between cognitive networks is constantly abnormal. Cognitive decline typically occurs after onset of LG syndrome in clinical settings and may be somewhat improved after epilepsy is controlled. The results of this study are consistent with the proposed hypothesis that the epilepsy of LG syndrome may result in Abnormal network behavior continuation. The occurrence of epileptic encephalopathy may be caused by the abnormal interaction between the persistent cognitive networks.