Dynamic properties of HFOs and spikes in the intra-operative electrocortigram in patients with focal cortical dysplasia

E. Schaft, D. Sun, M. van't Klooster, D. van Blooijs, P. Smits, W. Zweiphenning, P. Gosselaar, C. Ferrier, M. Zijlmans

Research output: Contribution to journalMeeting AbstractAcademic

Abstract

Purpose:High frequency oscillations (HFOs) and spikes are known biomarkers for the epileptogenic focus. HFOs seem to have advantages overspikes, due to their specific-ity for the epileptogenic focus. The specific characteristics of HFOs and spikes for different pathologies in the intra- operative ECoG (ioECoG) has not been extensively in-vestigated, while pathology specific knowledge can guide neurosurgeons during epilepsy surgery. We investigated the dynamics of HFOs and spikes for focal cortical dyspla-sia (FCD) patients with respect to the distribution, spread-ing and temporal properties.Methods:People with epilepsy who underwent an io-ECoG (4x5 AD- Tech grid) tailored resection, were se-lected from the UMCU RESPect database. Inclusion criteria were FCD confirmed by pathology and an Engel 1A outcome 1y post resection. Spikes, ripples (80- 250Hz) and fast ripples (250- 500Hz) in 1 minute ioECoG epochs pre- resectionwere automatically detected and visually-checked. We compared the total number of events in- and outside resected area (RA, non- RA; independent t- test). We analyzed the timing of the HFOs and spikes by com-paring the timing of HFOs in respect to the peak of the spike.Results:We selected 22 patients (mean 19.2y) with FCD type 1A (n = 2), 2A (n = 6) and 2B (n = 14). Spikes were found in 21 patients, ripples in 20 patients and fast ripples in 6 patients. The number of events found in electrodes covering the RA, edge and non- RA are for spikes: 1676, 265 and 746 (RA vs non- RA p < 0.01); ripples: 977, 20 and 108 (p < 0.01); fast ripples (FR): 214, 0 and 0 (p = 0.01). Ripples on spikes occurred at the time of the peak, while fast ripples on spikes occurred on the rising flank of the spike.Conclusion:FCD pathology is characterized by statisti-cally difference in the number of ioECoG events, espe-cially HFOs, between resected and not- resected tissue. This suggests that HFOs can be used to tailor epilepsy sur-gery in patients with FCD.
Original languageEnglish
Pages (from-to)103-103
JournalEpilepsia
Volume63
Issue numberS2
DOIs
Publication statusPublished - Sept 2022

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