High‐frequency oscillations detected in ECoG recordings correlate with cavernous malformation and seizure‐free outcome in a child with focal epilepsy: A case report

Abstract

SummaryEpilepsy associated with cavernous malformation (CM) often requires surgical resection of seizure focus to achieve seizure‐free outcome. High‐frequency oscillations (HFOs) in intracranial electroencephalogram (EEG) are reported as potential biomarkers of epileptogenic regions, but to our knowledge there are no data on the existence of HFOs in CM‐caused epilepsy. Here we report our experience of the identification of the seizure focus in a 3‐year‐old pediatric patient with intractable epilepsy associated with CM. The electrocorticographic recordings were obtained from a 64‐contact grid over 2 days in the epilepsy monitoring unit (EMU). The spatial distribution of HFOs and epileptic spikes were estimated from recording segments right after the electrode placement, during sleep and awake states separately. The HFO distribution showed consistency with the perilesional region; the location of spikes varied over days and did not correlate with the lesion. The HFO spatial distribution was more compact in sleep state and pinpointed the contacts sitting on the CM border. Following the resection of the CM and the hemosiderin ring, the patient became seizure‐free. This is the first report describing HFOs in a pediatric patient with intractable epilepsy associated with CM and shows their potential in identifying the seizure focus.

Trends in the use of automated algorithms for the detection of high‐frequency oscillations associated with human epilepsy

“…Other studies reported that that concurrent HFO and low frequency oscillations were a better marker than either alone, 79 and that a machine learning technique could be used to automatically rank and classify channels inside and outside the SOZ based on HFO rate 80 . The significance of HFOs as a predictor of outcome compared to spikes is not clear, as two studies reported conflicting results on this 36,88 …”

Latent Phase Identification of High-Frequency Micro-Scale Gamma Spike Transients in the Hypoxic Ischemic EEG of Preterm Fetal Sheep Using Spectral Analysis and Fuzzy Classifiers

“…Fusion techniques such as the combination of local spectral energy assessments of EEG segments in conjunction with Fourier and wavelet transforms have been shown to be helpful in the automatic classification of fast ripples and interictal epileptic spikes from an EEG background [28]. Research have indicated that high-frequency oscillations (HFO) and epileptic spikes in the ECoG recordings of 3-year-old children can be identified using STFT and time-frequency approaches [29]. Spectral time-frequency analysis have been demonstrated to automatically identify human intracranial HFOs from artefact and other EEG background activity with good specificity of greater than 90% [30].…”

Protocol for multicentre comparison of interictal high-frequency oscillations as a predictor of seizure freedom

“…Interictal HFO are discussed to be more specific than interictal spikes in localizing the SOZ or being in agreement with seizure outcome in several studies. 7–13 Many studies present HFO rates in relation to SOZ electrodes (for a review see 14 ). Fewer studies analyse the resection of interictal HFO, marked prospectively, to test agreement with postsurgical seizure freedom.…”