Tomlinson Samuel B, Khambhati Ankit N, Bermudez Camilo, Kamens Rebecca M, Heuer Gregory G, Porter Brenda E, Marsh Eric D
Department of Pediatrics, Division of Child Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, United States; School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, NY, 14642, United States.
Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, 19104, United States; Penn Center for Neuroengineering and Therapeutics, University of Pennsylvania, Philadelphia, PA, 19104, United States.
Epilepsy Res. 2018 Jul;143:41-49. doi: 10.1016/j.eplepsyres.2018.04.003. Epub 2018 Apr 5.
Post-ictal EEG alterations have been identified in studies of intracranial recordings, but the clinical significance of post-ictal EEG activity is undetermined. The purpose of this study was to examine the relationship between peri-ictal EEG activity, surgical outcome, and extent of seizure propagation in a sample of pediatric epilepsy patients.
Intracranial EEG recordings were obtained from 19 patients (mean age = 11.4 years, range = 3-20 years) with 57 seizures used for analysis (mean = 3.0 seizures per patient). For each seizure, 3-min segments were extracted from adjacent pre-ictal and post-ictal epochs. To compare physiology of the epileptic network between epochs, we calculated the relative delta power (Δ) using discrete Fourier transformation and constructed functional networks based on broadband connectivity (conn). We investigated differences between the pre-ictal (Δ, conn) and post-ictal (Δ, conn) segments in focal-network (i.e., confined to seizure onset zone) versus distributed-network (i.e., diffuse ictal propagation) seizures.
Distributed-network (DN) seizures exhibited increased post-ictal delta power and global EEG connectivity compared to focal-network (FN) seizures. Following DN seizures, patients with seizure-free outcomes exhibited a 14.7% mean increase in delta power and an 8.3% mean increase in global connectivity compared to pre-ictal baseline, which was dramatically less than values observed among seizure-persistent patients (29.6% and 47.1%, respectively).
Post-ictal differences between DN and FN seizures correlate with post-operative seizure persistence. We hypothesize that post-ictal deactivation of subcortical nuclei recruited during seizure propagation may account for this result while lending insights into mechanisms of post-operative seizure recurrence.
在颅内记录研究中已识别出发作后脑电图改变，但发作后脑电图活动的临床意义尚未确定。本研究的目的是在一组小儿癫痫患者样本中，研究发作期周围脑电图活动、手术结果和癫痫传播范围之间的关系。
从19例患者（平均年龄 = 11.4岁，范围 = 3 - 20岁）获取颅内脑电图记录，对57次发作进行分析（平均每位患者3.0次发作）。对于每次发作，从相邻的发作前和发作后时段提取3分钟片段。为了比较各时段癫痫网络的生理学特征，我们使用离散傅里叶变换计算相对δ功率（Δ），并基于宽带连通性（conn）构建功能网络。我们研究了局灶性网络（即局限于癫痫发作起始区）与分布式网络（即广泛的发作传播）发作的发作前（Δ，conn）和发作后（Δ，conn）片段之间的差异。
与局灶性网络（FN）发作相比，分布式网络（DN）发作表现出发作后δ功率增加和脑电图整体连通性增加。在DN发作后，无癫痫发作结果的患者与发作前基线相比，δ功率平均增加14.7%，整体连通性平均增加8.3%，这显著低于癫痫持续患者中观察到的值（分别为29.6%和47.1%）。
DN和FN发作之间的发作后差异与术后癫痫持续相关。我们假设，在癫痫传播过程中募集的皮质下核团在发作后失活可能解释了这一结果，同时也为术后癫痫复发机制提供了见解。
