OBJECTIVE Localization of epileptogenic brain regions is a crucial aim of pre-surgical evaluation of patients with drug-resistant epilepsy. Several methods have been proposed to identify the seizure onset zone, particularly based on the detection of fast activity. Most of these methods are inefficient to detect slower patterns of onset that account for 20-30% of commonly observed Stereo-Electro-Encephalography (SEEG) patterns. We seek to evaluate the performance of a new quantified measure called the Connectivity Epileptogenicity Index (cEI) in various types of seizure onset patterns. METHODS We studied SEEG recorded seizures from 51 patients, suffering from focal drug-resistant epilepsy. The cEI combines a directed connectivity measure ("out-degrees") and the original epileptogenicity index (EI). Quantified results (Out-degrees, cEI and EI) were compared to visually defined seizure onset zone (vSOZ). We computed recall (sensitivity) and precision (proportion of correct detections within all detections) with vSOZ as a reference. The quality of the detector was quantified by the area under the precision-recall curve. RESULTS Best results (in terms of match with vSOZ) were obtained for cEI. For seizures with fast onset patterns, cEI and EI gave comparable results. For seizures with slow onset patterns, cEI gave a better estimation of the vSOZ than EI. CONCLUSIONS We observed that cEI discloses better performance than EI when seizures starts with slower patterns and equal to EI in seizures with fast onset patterns. SIGNIFICANCE The cEI is a promising new tool for epileptologists, that helps characterizing the seizure onset zone in sEEG, in a robust way despite variations in seizure onset patterns.

中文翻译：

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“连通性致癫痫指数”（cEI），一种在立体脑电图记录癫痫发作中绘制不同癫痫发作模式的方法

目标致癫痫脑区的定位是对耐药性癫痫患者进行术前评估的关键目标。已经提出了几种方法来识别癫痫发作区，特别是基于快速活动的检测。大多数这些方法在检测占常见立体脑电图 (SEEG) 模式的 20-30% 的较慢的发作模式方面效率低下。我们试图评估一种称为连通性致癫痫指数 (cEI) 的新量化指标在各种类型的癫痫发作模式中的表现。方法 我们研究了 51 名患有局灶性耐药性癫痫的患者的 SEEG 记录癫痫发作。cEI 结合了定向连接测量（“出度”）和原始致癫痫指数 (EI)。量化结果（度数，cEI 和 EI) 与视觉定义的癫痫发作区 (vSOZ) 进行了比较。我们以 vSOZ 作为参考计算了召回率（灵敏度）和精度（所有检测中正确检测的比例）。检测器的质量通过精确召回曲线下的面积来量化。结果 cEI 获得了最佳结果（就与 vSOZ 的匹配而言）。对于快速发作模式的癫痫发作，cEI 和 EI 给出了可比较的结果。对于缓慢发作模式的癫痫发作，cEI 比 EI 对 vSOZ 给出了更好的估计。结论 我们观察到，当癫痫以较慢的模式开始时，cEI 比 EI 表现出更好的性能，并且在快速发作模式中与 EI 相同。意义 cEI 是癫痫学家有前途的新工具，有助于表征 sEEG 中的癫痫发作区，