High-frequency oscillations (HFOs) have been proposed as a promising biomarker of the epileptogenic zone (EZ). But accurate delineation of EZ based on HFOs is still challenging. Our study compared HFOs from EZ and non-EZ on the basis of their associations with interictal slow waves, aiming at exploring a new way to localize EZ. Nineteen medically intractable epilepsy patients with good surgical outcome were included. Five minute interictal intracranial electroencephalography (EEG) epochs of slow-wave sleep were randomly selected; then ripples (80–200 Hz), fast ripples (FRs; 200–500 Hz), and slow waves (0.1–4 Hz) were automatically analyzed. The EZ and non-EZ were identified by resection range during the surgeries. We found that both ripples and FRs superimposed more frequently on slow waves in EZ than in non-EZ (P < 0.01). Although ripples preferred to occur on the down state of slow waves in both two groups, ripples in EZ tended to be closer to the down-state peak of slow wave than in non-EZ (-174 vs. -231 ms, P = 0.008). As for FR, no statistical difference was found between the two groups (P = 0.430). Additionally, slow wave-containing ripples in EZ had a steeper slope (1.7 vs. 1.5 μV/ms, P < 0.001) and wider distribution ratio (32.3 vs. 30.1%, P < 0.001) than those in the non-EZ. But for slow wave-containing FR, only a steeper slope (1.7 vs. 1.4 μV/ms, P < 0.001) was observed. Our study innovatively compared the different features of association between HFOs and slow wave in EZ and non-EZ from refractory focal epilepsy with good surgical outcome, proposing a new method to localize EZ and facilitating the surgical plan.

中文翻译：

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具有良好手术效果的难治性局灶性癫痫发作间期高频振荡与慢波的关系

高频振荡 (HFO) 已被提议作为癫痫发生区 (EZ) 的有希望的生物标志物。但基于 HFO 准确描绘 EZ 仍然具有挑战性。我们的研究根据 EZ 和非 EZ 的 HFO 与发作间期慢波的关联来比较它们，旨在探索一种定位 EZ 的新方法。包括 19 名手术结果良好的医学上顽固性癫痫患者。随机选择慢波睡眠的 5 分钟发作间期颅内脑电图 (EEG) epochs；然后自动分析波纹 (80–200 Hz)、快速波纹 (FRs; 200–500 Hz) 和慢波 (0.1–4 Hz)。EZ 和非 EZ 在手术过程中通过切除范围来确定。我们发现涟漪和 FRs 在 EZ 中比在非 EZ 中更频繁地叠加在慢波上（P < 0.01）。尽管两组中的慢波都倾向于出现在慢波的下行状态，但与非 EZ 相比，EZ 中的涟漪更接近慢波的下行峰值（-174 vs. -231 ms，P = 0.008 ）。至于FR，两组之间没有发现统计学差异（P = 0.430）。此外，与非 EZ 相比，EZ 中包含慢波的波纹具有更陡峭的斜率（1.7 对 1.5 μV/ms，P < 0.001）和更宽的分布比（32.3 对 30.1%，P < 0.001）。但对于包含慢波的 FR，仅观察到更陡峭的斜率（1.7 对 1.4 μV/ms，P < 0.001）。我们的研究创新地比较了具有良好手术效果的难治性局灶性癫痫的 EZ 和非 EZ 中 HFO 与慢波关联的不同特征，提出了一种定位 EZ 并促进手术计划的新方法。