We found that phase cone clustering patterns in EEG ripple bands demonstrate an increased turnover rate in epileptogenic zones compared to adjacent regions. We employed 256 channel EEG data collected in four adult subjects with refractory epilepsy. The analysis was performed in the 80–150 and 150–250 Hz ranges. Ictal onsets were documented with intracranial EEG recordings. Interictal scalp recordings, free of epileptiform patterns, of 240-s duration, were selected for analysis for each subject. The data was filtered, and the instantaneous phase was extracted after the Hilbert transformation. Spatiotemporal contour plots of the unwrapped instantaneous phase with 1.0 ms intervals were constructed using a montage layout of the 256 electrode positions. Stable phase cone patterns were selected based on criteria that the sign of spatial gradient did not change for a minimum of three consecutive time samples and the frame velocity was consistent with known propagation velocities of cortical axons. These plots exhibited increased dynamical formation and dissolution of phase cones in the ictal onset zones, compared to surrounding cortical regions, in all four patients. We believe that these findings represent markers of abnormally increased cortical excitability. They are potential tools that may assist in localizing the epileptogenic zone.

中文翻译：

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发作间期癫痫发生区 80–250 Hz 波段的相位锥转换增加

我们发现 EEG 波纹带中的相位锥聚类模式表明，与相邻区域相比，致痫区的周转率增加。我们采用了在四名难治性癫痫成年受试者中收集的 256 通道 EEG 数据。分析在 80-150 和 150-250 Hz 范围内进行。颅内 EEG 记录记录了发作性发作。选择发作间期头皮记录，无癫痫样模式，持续时间为 240 秒，用于分析每个受试者。对数据进行过滤，并在希尔伯特变换后提取瞬时相位。使用 256 个电极位置的蒙太奇布局构建了间隔为 1.0 ms 的展开瞬时相位的时空等高线图。稳定相位锥模式的选择标准是空间梯度的符号在至少三个连续时间样本中没有改变，并且帧速度与已知的皮质轴突传播速度一致。在所有四名患者中，与周围皮质区域相比，这些图显示出在发作起始区的相锥的动态形成和溶解增加。我们相信这些发现代表了皮质兴奋性异常增加的标志。它们是可能有助于定位致痫区的潜在工具。与周围皮质区域相比，在所有四名患者中。我们相信这些发现代表了皮质兴奋性异常增加的标志。它们是可能有助于定位致痫区的潜在工具。与周围皮质区域相比，在所有四名患者中。我们相信这些发现代表了皮质兴奋性异常增加的标志。它们是可能有助于定位致痫区的潜在工具。