Montreal Neurological Institute and Department of Neurology & Neurosurgery, McGill University, Montréal, H3A 2B4 QC, Canada.
J Neurosci Methods. 2012 Nov 15;211(2):265-71. doi: 10.1016/j.jneumeth.2012.09.003. Epub 2012 Sep 13.
High-frequency oscillations (HFOs, ripples: 80-200 Hz, fast ripples: 250-500 Hz) recorded from the epileptic brain are thought to reflect abnormal network-driven activity. They are also better markers of seizure onset zones compared to interictal spikes. There is thus an increasing number of studies analysing HFOs in vitro, in vivo and in the EEG of human patients with refractory epilepsy. However, most of these studies have focused on HFOs during interictal events or at seizure onset, and few have analysed HFOs during seizures. In this study, we are comparing three different automated methods of HFO detection to two methods of visual analysis, during the pre-ictal, ictal and post-ictal periods on multiple channels using the rat pilocarpine model of temporal lobe epilepsy. The first method (method 1) detected HFOs using the average of the normalised period, the second (method 2) detected HFOs using the average of the normalised period in 1s windows and the third (method 3) detected HFOs using the average of a reference period before seizure onset. Overall, methods 2 and 3 showed higher sensitivity compared to method 1. When dividing the analysed traces in pre-, ictal and post-ictal periods, method 3 showed the highest sensitivity during the ictal period compared to method 1, while method 2 was not significantly different from method 1. These findings suggest that method 3 could be used for automated and reliable detection of HFOs on large data sets containing multiple channels during the ictal period.
高频振荡（HFOs，涟漪：80-200Hz，快速涟漪：250-500Hz）被认为反映了异常的网络驱动活动，从癫痫患者的大脑中记录下来。与发作间期棘波相比，它们也是发作起始区更好的标志物。因此，越来越多的研究分析了体外、体内和难治性癫痫患者 EEG 中的 HFO。然而，这些研究大多集中在发作间期事件或发作起始时的 HFO，很少有分析发作期间的 HFO。在这项研究中，我们比较了三种不同的 HFO 自动检测方法与两种视觉分析方法，使用匹鲁卡品诱导的颞叶癫痫大鼠模型，在多个通道上的预发作、发作中和发作后期间进行分析。第一种方法（方法 1）使用归一化周期的平均值检测 HFO，第二种方法（方法 2）使用 1s 窗口内归一化周期的平均值检测 HFO，第三种方法（方法 3）使用发作前参考期的平均值检测 HFO。总的来说，方法 2 和方法 3 的灵敏度高于方法 1。当将分析轨迹分为预发作、发作中和发作后期间时，方法 3 在发作期间的灵敏度高于方法 1，而方法 2与方法 1无显著差异。这些发现表明，方法 3 可用于在包含多个通道的大数据集上自动且可靠地检测发作期间的 HFO。
