Ictal high-frequency oscillations and hyperexcitability in refractory epilepsy

Clinical Neurophysiology : Official Journal of the International Federation of Clinical Neurophysiology
Howan LeungLawrence K S Wong

Abstract

High-frequency oscillations (HFOs, 80-500Hz) from intracranial electroencephalography (EEG) may represent a biomarker of epileptogenicity for epilepsy. We explored the relationship between ictal HFOs and hyperexcitability with a view to improving surgical outcome. We evaluated 262 patients with refractory epilepsy. Fifteen patients underwent electrode implantation, and surgical resection was performed in 12 patients using a semi-prospective design. Ictal intracranial EEGs were examined by continuous wavelet transform (CWT). Significant ictal HFOs were denoted by normalized wavelet power above the 50th percentile across all channels. Each patient underwent functional mapping with cortical electrical stimulation. Hyperexcitability was defined as the appearance of afterdischarges or clinical seizures after electrical stimulation (50Hz, biphasic, pulse width=0.5ms, 5s, 5mA). Among the group of patients achieving Engel Class I/II outcome at 1+ year, the mean proportion of significant ictal HFOs among resected channels for any given patient was 69% (33.3-100%). The respective figures for conventional frequency ictal patterns (CFIPs), hyperexcitability, and radiological lesion were 68.3% (26.3-100%), 39.6% (0-100%), and 52.8% (0-100%)...Continue Reading

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Citations

Feb 26, 2019·Frontiers in Neurology·Aljoscha ThomschewskiBirgit Frauscher
Sep 5, 2019·Journal of Epilepsy Research·Chae Jung Park, Seung Bong Hong
Jul 26, 2019·Nature Reviews. Neurology·Maeike ZijlmansNicole van Klink
Apr 1, 2021·Cognitive Neurodynamics·Chuanzuo YangFeng Zhai

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