Epilepsy Center, University of Freiburg, Freiburg, Germany.
Epilepsia. 2015 Feb;56(2):197-206. doi: 10.1111/epi.12844. Epub 2014 Dec 30.
Interictal high frequency oscillations (HFOs) are a promising candidate as a biomarker in epilepsy as well as for defining the seizure-onset zone as for the prediction of the surgical outcome after epilepsy surgery. The purpose of the study is to investigate properties of HFOs in long-term recordings with respect to the sleep-wake cycle and anatomic regions to verify previous results based on observations from short intervals and patients mainly with temporal lobe epilepsy to the analysis of hours of recordings and focal epilepsies with extratemporal origin.
Automatic HFO detection using a radial basis function neural network detector was performed in long-term recordings of 15 presurgical patients investigated with subdural strip, grid, and depth contacts. Periods with visual marked sleep stages based on parallel scalp recordings from two consecutive nights were compared to awake intervals. Statistical analysis was based on the Kruskal-Wallis test, Mann-Whitney U-test and Spearman's rank correlations.
HFO rates in seizure-onset contacts differed from other brain regions independent of the sleep-wake cycle. For temporal contacts, the HFO rate increased significantly with sleep stage. In addition, contacts covering the parietal lobe, including rolandic cortex, showed a significant increase of HFO rates during sleep. However, no significant HFO rate changes depending on the sleep-wake cycle were found for frontal contacts.
The rate of interictal HFOs predicted the SOZ with statistical significance at the group level, but properties other than the HFO rate may need to be considered to improve the diagnostic utility of HFOs. This study gives evidence that the modulation of HFO rates by states of the sleep-wake cycle has particular characteristics within different neocortical regions and in mesiotemporal structures, and contributes to the establishment of HFOs as a biomarker in epilepsy.
发作间期高频振荡（HFOs）是癫痫的一种有前途的生物标志物候选物，可用于定义发作起始区，预测癫痫手术后的手术结果。本研究的目的是研究与睡眠-觉醒周期和解剖区域相关的 HFOs 的特性，以验证基于短时间间隔和主要颞叶癫痫患者观察结果的先前结果，分析数小时的记录和具有颞外起源的局灶性癫痫。
使用径向基函数神经网络检测器对 15 例接受硬膜下条带、网格和深度接触的术前患者的长期记录进行自动 HFO 检测。根据来自两个连续晚上的平行头皮记录对具有明显视觉标记的睡眠阶段的时间段与清醒间隔进行比较。统计分析基于 Kruskal-Wallis 检验、Mann-Whitney U 检验和 Spearman 秩相关。
发作起始接触的 HFO 率与睡眠-觉醒周期无关，与其他脑区不同。对于颞叶接触，HFO 率随睡眠阶段显著增加。此外，包括 Rolandic 皮质在内的覆盖顶叶的接触在睡眠期间 HFO 率显著增加。然而，对于额叶接触，未发现 HFO 率随睡眠-觉醒周期变化的显著差异。
HFO 的发作间期率在组水平上具有统计学意义地预测了 SOZ，但除 HFO 率以外的特性可能需要考虑以提高 HFO 的诊断效用。这项研究表明，HFO 率受睡眠-觉醒周期状态的调制具有不同新皮层区域和中颞叶结构的特定特征，并为 HFO 作为癫痫的生物标志物的建立做出了贡献。
