Sumsky Stefan L, Santaniello Sabato
Annu Int Conf IEEE Eng Med Biol Soc. 2018 Jul;2018:2288-2291. doi: 10.1109/EMBC.2018.8512742.
Ripples (80-250 Hz) are brief high-frequency oscillations that are often detected in intracranial EEG (iEEG) and are currently investigated as a potential biomarker to facilitate the Iocalization of the seizure onset zone (SOZ) in patients with drug-resistant epilepsy. While the rate and shape of these oscillations have been positively correlated with the SOZ, the temporal pattern of these oscillations in the epileptic brain still requires investigation. In this study, we investigate the temporal pattern of ripple events in five patients with temporal lobe epilepsy (TLE), which is one of the most common forms of epilepsy. The rate of ripple events is positively correlated with the SOZ in TLE but its diagnostic utility in localizing the SOZ remains unclear, which suggests that additional ripple-related features should be investigated. By combining point process modeling and cluster analysis, we show that a recurrent, non-stationary bursting pattern characterizes the SOZ channels consistently across patients, while the non-SOZ channels have poor between-channel similarity and no consistent pattern over time nor across patients. Furthermore, the degree of separation between SOZ and non-SOZ model parameter vectors is significantly higher (ANOVA test, ${P}$-value $P\lt 0.01$) than the degree of separation between the ripple rates, which suggests that the temporal pattern more than the rate may contribute to the pre- surgical Iocalization of the SOZ.
涟漪波（80 - 250赫兹）是短暂的高频振荡，常在颅内脑电图（iEEG）中检测到，目前正作为一种潜在的生物标志物进行研究，以促进耐药性癫痫患者癫痫发作起始区（SOZ）的定位。虽然这些振荡的频率和形状与SOZ呈正相关，但癫痫大脑中这些振荡的时间模式仍有待研究。在本研究中，我们调查了五名颞叶癫痫（TLE）患者（TLE是最常见的癫痫形式之一）中涟漪波事件的时间模式。TLE中涟漪波事件的频率与SOZ呈正相关，但其在定位SOZ方面的诊断效用仍不明确，这表明应研究其他与涟漪波相关的特征。通过结合点过程建模和聚类分析，我们发现一种反复出现的、非平稳的爆发模式在患者中一致地表征了SOZ通道，而非SOZ通道在通道间相似性较差，且随时间和患者个体均无一致模式。此外，SOZ和非SOZ模型参数向量之间的分离程度显著高于涟漪波频率之间的分离程度（方差分析检验，P值P < 0.01），这表明时间模式而非频率可能有助于SOZ的术前定位。
