Spontaneous and electrically-induced cortical excitability changes of epileptic networks after radio-frequency thermo-coagulation

癫痫是一种网络疾病。癫痫活动在大脑中传播迅速，即使在局灶性癫痫中，癫痫间期活动也可能涉及广泛的大脑区域。癫痫大脑显示永久性广泛变化的迹象，但尽管有这些观察结果，患者在癫痫发作的局灶性切除后不再发作。因此，癫痫活动的局灶发生器很可能是更大的癫痫网络的一部分，并与生理脑活动相互作用，然而，这种现象的程度和临床相关性知之甚少。RFTC（射频热凝）慢性。立体定向脑电图（SEEG）记录是一种新的微创治疗顽固性癫痫的方法。它可以用来消除慢性SEEG调查期间癫痫发作的焦点。在局灶性和广泛的癫痫网络相互作用的背景下，这种治疗提供了独特的机会来评估癫痫灶消融后脑内脑电图癫痫网络的变化，并将这些变化与癫痫发作结果联系起来。80-500Hz之间的高频振荡（HFO）在记忆巩固等生理过程中被描述为癫痫组织的新焦点标记。回顾性研究表明，切除HFO生成组织与术后癫痫发作结果相关。然而，我们中心的一项前瞻性研究表明，术前在脑内脑电图记录中发现的HFO不能预测单个患者的癫痫发作结果。急性术中颅内脑电图记录可以比较术前和术后的HFO网络，并提示术后HFO测量在预测术后癫痫发作结果方面更可靠。此外，皮质-皮质诱发电位可以用来探测癫痫网络和评估诱发的HFO。法国格勒诺布尔癫痫中心和德国弗莱堡癫痫中心的合作项目将通过与睡眠模式的相关性分析来区分生理性和癫痫性HFO。然后分析RFTC干预前后CCEP（皮质-皮质诱发电位）网络的变化以及癫痫性HFO和癫痫性尖峰的区域扩散。以下假设将被检验：1) RFTC对癫痫病灶的隔离可以通过CCEP测量的癫痫HFO降低和皮质兴奋性降低来测量，2)介入后HFO和CCEP分析可用于改善介入后癫痫发作结果的预测，3)在未从RFTC获益的患者中，CCEP期间剩余的HFO网络和高频活动信息有助于预测连续切除手术后的癫痫发作结果。

Epilepsy is a network disease. Epileptic activity travels fast though the brain and even in focal epilepsies inter-ictal epileptic activity can involve widespread brain regions. Epileptic brain show sign of permanent widespread changes but despite these observations patients become seizure free after focal resections of the seizure onset. It is therefore likely that a focal generator of epileptic activity is part of a larger epileptic network, and interacts with physiological brain activity, the extent and clinical relevance of this phenomenon however is poorly understood. RFTC (Radiofrequency thermocoagulation) during chronic. Stereotactic intracerebral EEG (SEEG) recordings is a new minimally invasive treatment for patients with refractory epilepsy. It can be used to try to eliminate a seizure focus during the chronic SEEG investigation. In the context of focal and widespread epileptic network interactions this treatment provides the unique opportunity to assess changes in epileptic networks with intracerebral EEG after ablation of the epileptic focus and correlate these changes with seizure outcome. High frequency oscillations (HFO) between 80-500Hz are described during physiological processes such as memory consolidation and as new focal markers for epileptic tissue. Retrospective studies suggest that the removal of HFO generating tissue correlates with the postsurgical seizure outcome. Nevertheless a prospective study from our center indicates that HFO identified presurgically during intracerebral EEG recordings do not allow predicting seizure outcome in individual patients. Acute intraoperative intracranial EEG recordings allow comparing HFO networks prior and after surgery and suggest that the postsurgical measurement of HFO are more reliable in predicting postoperative seizure outcome. Moreover cortico-cortical evoked potentials can be used to probe epileptic networks and assess evoked HFO. This collaborative project between the Epilepsy Centers in Grenoble, France and Freiburg, Germany patients will differentiate between physiological and epileptic HFO using correlation analysis with sleep pattern. Changes in CCEP (cortico-cortical evoked potentials) network and regional spread of epileptic HFO and epileptic spikes will then be analyzed prior and after RFTC intervention. The following hypothesis will be tested: 1) Isolation of the epileptic focus by RFTC can be measured by a reduction of epileptic HFO and reduced cortical excitability as measured with CCEP, 2) Post-interventional HFO and CCEP analysis may be used to improve prediction of post-interventional seizure outcome, 3) In patients which fail to profit from RFTC remaining HFO networks and information from high frequency activity during CCEP help to predict seizure outcome after the consecutive resective surgery.