Müller Michael, Dekkers Martijn, Wiest Roland, Schindler Kaspar, Rummel Christian
Support Center for Advanced Neuroimaging (SCAN), University Institute for Diagnostic and Interventional Neuroradiology, Inselspital, Bern, Switzerland.
Department of Neurology, Inselspital, Bern University Hospital, University Bern, Bern, Switzerland.
Front Neurol. 2022 Jan 13;12:741450. doi: 10.3389/fneur.2021.741450. eCollection 2021.
Epilepsy surgery can be a very effective therapy in medication refractory patients. During patient evaluation intracranial EEG is analyzed by clinical experts to identify the brain tissue generating epileptiform events. Quantitative EEG analysis increasingly complements this approach in research settings, but not yet in clinical routine. We investigate the correspondence between epileptiform events and a specific quantitative EEG marker. We analyzed 99 preictal epochs of multichannel intracranial EEG of 40 patients with mixed etiologies. Time and channel of occurrence of epileptiform events (spikes, slow waves, sharp waves, fast oscillations) were annotated by a human expert and non-linear excess interrelations were calculated as a quantitative EEG marker. We assessed whether the visually identified preictal events predicted channels that belonged to the seizure onset zone, that were later resected or that showed strong non-linear interrelations. We also investigated whether the seizure onset zone or the resection were predicted by channels with strong non-linear interrelations. In patients with temporal lobe epilepsy (32 of 40), epileptic spikes and the seizure onset zone predicted the resected brain tissue much better in patients with favorable seizure control after surgery than in unfavorable outcomes. Beyond that, our analysis did not reveal any significant associations with epileptiform EEG events. Specifically, none of the epileptiform event types did predict non-linear interrelations. In contrast, channels with strong non-linear excess EEG interrelations predicted the resected channels better in patients with temporal lobe epilepsy and favorable outcome. Also in the small number of patients with seizure onset in the frontal and parietal lobes, no association between epileptiform events and channels with strong non-linear excess EEG interrelations was detectable. In contrast to patients with temporal seizure onset, EEG channels with strong non-linear excess interrelations did neither predict the seizure onset zone nor the resection of these patients or allow separation between patients with favorable and unfavorable seizure control. Our study indicates that non-linear excess EEG interrelations are not strictly associated with epileptiform events, which are one key concept of current clinical EEG assessment. Rather, they may provide information relevant for surgery planning in temporal lobe epilepsy. Our study suggests to incorporate quantitative EEG analysis in the workup of clinical cases. We make the EEG epochs and expert annotations publicly available in anonymized form to foster similar analyses for other quantitative EEG methods.
癫痫手术对于药物难治性患者可能是一种非常有效的治疗方法。在患者评估期间,临床专家会分析颅内脑电图,以识别产生癫痫样事件的脑组织。定量脑电图分析在研究环境中越来越多地补充了这种方法,但尚未应用于临床常规。我们研究癫痫样事件与一种特定的定量脑电图标记之间的对应关系。我们分析了40例病因混合的患者的99个发作前期多通道颅内脑电图片段。由一名专家标注癫痫样事件(棘波、慢波、锐波、快速振荡)的发生时间和通道,并计算非线性超额相互关系作为定量脑电图标记。我们评估了视觉识别的发作前期事件是否能预测属于癫痫发作起始区、后来被切除或显示出强烈非线性相互关系的通道。我们还研究了具有强烈非线性相互关系的通道是否能预测癫痫发作起始区或切除术。在颞叶癫痫患者(40例中的32例)中,与手术效果不佳的患者相比,癫痫棘波和癫痫发作起始区在术后癫痫控制良好的患者中能更好地预测被切除的脑组织。除此之外,我们的分析未发现与癫痫样脑电图事件有任何显著关联。具体而言,没有一种癫痫样事件类型能预测非线性相互关系。相比之下,在颞叶癫痫且预后良好的患者中,具有强烈非线性超额脑电图相互关系的通道能更好地预测被切除的通道。在少数额叶和顶叶发作起始的患者中,也未检测到癫痫样事件与具有强烈非线性超额脑电图相互关系的通道之间存在关联。与颞叶发作的患者不同,具有强烈非线性超额相互关系的脑电图通道既不能预测这些患者的癫痫发作起始区,也不能预测切除术,也无法区分癫痫控制良好和不佳的患者。我们的研究表明,非线性超额脑电图相互关系与癫痫样事件并无严格关联,而癫痫样事件是当前临床脑电图评估的一个关键概念。相反,它们可能为颞叶癫痫的手术规划提供相关信息。我们的研究建议在临床病例检查中纳入定量脑电图分析。我们以匿名形式公开脑电图片段和专家标注,以促进对其他定量脑电图方法进行类似分析。