Evaluation of High frequency oscillations as markers of epileptogenicity in intracranial EEG and their correlates on surface EEG

对于难治性癫痫患者，手术切除致痫组织是最有希望的治疗方法。致痫组织的识别是复杂的；即使是现代成像技术和颅内脑电记录(IEEG)也不能可靠地预测手术后的结果。传统上，只有低于100赫兹的脑电频率用于临床目的，但技术进步现在允许我们记录更高的频率，采样率高达10,000赫兹。最近的研究表明，100赫兹以上的高频振荡(HFO)与致痫组织密切相关。然而，它们是在较小的皮质区域产生的，到目前为止只用iEEG电极记录，而不是用体表EEG记录。此外，对癫痫的HFO的研究可能会受到生理性HFO的干扰，因为生理性HFO不容易与病理事件区分开来。本项目旨在研究以下关于高频波在80-500赫兹之间的假设：1)高频波是致痫的可靠标记物。2)生理性和病理性HFO具有不同的电生理模式，与频率无关。3)在体表EEG上可以看到伴有癫痫棘波的HFO，从而可以更好地用非侵入性EEG来描绘致痫区域。

For patients with medically refractory epilepsy, surgical removal of epileptogenic tissue is the most promising treatment. The identification of epileptogenic tissue is complex; even modern imaging techniques and intracranial EEG recordings (iEEG) fail to reliably predict postsurgical outcome. Traditionally, only EEG frequencies below 100Hz are used for clinical purposes, but technical advancements now allow us to record higher frequencies with sampling rates up to 10000Hz. Recent studies have shown that high-frequency oscillations (HFOs) above 100 Hz are closely linked to epileptogenic tissue. They are however generated over small cortical areas and were until now only recorded with iEEG electrodes and not with surface EEG. Additionally, studies of epileptic HFOs may be confounded by physiological HFOs that cannot be easily distinguished from pathological events. This project aims to investigate the following hypotheses about HFOs between 80-500Hz: 1) HFOs are reliable markers of epileptogenicity. 2) Physiological and pathological HFOs have distinguishable electrophysiological patterns independent of frequency 3) HFOs occurring with epileptic spikes can be seen on surface EEG, allowing better delineation of epileptogenic areas with non-invasive EEG.