Wu Dan, Zhang Wei, Lu Hongjuan, Liu Xingzhou, Sun Wei
Department of Neurology, Xuanwu Hospital Capital Medical University, Beijing, China.
Department of Neurology, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Beijing, China.
Epilepsy Res. 2021 Aug;174:106676. doi: 10.1016/j.eplepsyres.2021.106676. Epub 2021 May 21.
To investigate the characteristics of transition from interictal to ictal phase in intracranial recordings and further to determine the potential marker of epileptogenic zone.
Eighteen patients with drug-refractory epilepsy who underwent stereo-electroencephalography (SEEG) evaluation and subsequent resective surgery were included. All patients were seizure-free post-operatively. The recorded seizures were retrospectively reviewed and time episodes including 5 min before electrographic onset were selected for further analysis to verify the presence of a transitional pattern in the transitional phase, which was distinct from interictal background and ictal onset. Besides, the components of transitional patterns which characterized by different pathological waveforms were identified by visual analysis and time-frequency analysis. The prevalence of transitional patterns between resection and non-resection, lesion and non-lesion sites were compared. In addition, the association between transitional patterns and types of epilepsy was explored.
Six transitional patterns characterized by different combinations of multiple pathological waveforms by visual analysis combined with time-frequency analysis were identified: spike/spike-waves/polyspikes; spike superimposed by HFOs; spike superimposed by gamma oscillations; spike followed by suppression; spike superimposed by HFOs and followed by suppression; and spike superimposed by gamma oscillations and followed by suppression. A higher prevalence of transitional patterns in resection than non-resection (p < 0.001) and in lesion than non-lesion contacts (p < 0.001). The pattern characterized by spike superimposed by HFOs and followed by suppression was more prevalent in resection than non-resection sites (p = 0.004). Further, there was an association between the complexity of transitional patterns and the location of contacts. Patterns with higher degree of complexity were more likely to be inside the resection area (p = 0.035). Besides, we found the pattern with spike superimposed by HFOs was associated more with limbic epilepsy than neocortical epilepsy (p < 0.001), whereas another 3 patterns, spike superimposed by gamma oscillation, spike followed by suppression and spike combined with HFOs and suppression, were observed more frequently in neocortical epilepsy than limbic epilepsy (p = 0.018, 0.011 and < 0.001, respectively).
Transitional patterns from interictal to ictal state were characterized by different combinations of multiple pathological waveforms, which may be a potential marker of epileptogenic zone. Our findings support that the interaction of different neuronal oscillations or waveforms generated by different neuronal populations may be the potential mechanism of seizure generation.
研究颅内记录中发作间期到发作期转变的特征，并进一步确定致痫区的潜在标志物。
纳入18例接受立体定向脑电图（SEEG）评估及后续切除手术的药物难治性癫痫患者。所有患者术后均无癫痫发作。对记录的癫痫发作进行回顾性分析，选择脑电图发作前5分钟的时间段进行进一步分析，以验证转变期是否存在不同于发作间期背景和发作起始的转变模式。此外，通过视觉分析和时频分析确定以不同病理波形为特征的转变模式的组成部分。比较切除部位与非切除部位、病变部位与非病变部位之间转变模式的发生率。此外，探讨转变模式与癫痫类型之间的关联。
通过视觉分析及时频分析，确定了六种以多种病理波形不同组合为特征的转变模式：棘波/棘慢波/多棘波；由高频振荡叠加的棘波；由伽马振荡叠加的棘波；棘波后跟随抑制；由高频振荡叠加后跟随抑制的棘波；由伽马振荡叠加后跟随抑制的棘波。切除部位的转变模式发生率高于非切除部位（p < 0.001），病变部位的接触点高于非病变接触点（p < 0.001）。以高频振荡叠加后跟随抑制为特征的模式在切除部位比非切除部位更常见（p = 0.004）。此外，转变模式的复杂性与接触点位置之间存在关联。复杂性较高的模式更可能位于切除区域内（p = 0.035）。此外，我们发现由高频振荡叠加的棘波模式与边缘叶癫痫的相关性高于新皮质癫痫（p < 0.001），而另外三种模式，由伽马振荡叠加的棘波、棘波后跟随抑制以及棘波与高频振荡和抑制相结合的模式，在新皮质癫痫中比边缘叶癫痫更常见（分别为p = 0.018、0.011和< 0.001）。
发作间期到发作期的转变模式以多种病理波形的不同组合为特征，这可能是致痫区的潜在标志物。我们的研究结果支持不同神经元群体产生的不同神经元振荡或波形之间的相互作用可能是癫痫发作产生的潜在机制。
