High frequency oscillations in intra- operative electrocorticography before and after epilepsy surgery

N. E. C. van Klink*, M.A. van 't Klooster, R. Zelmann, F. S. S. Leijten, H. Ferrier, K. P. J. Braun, P. C. van Rijen, M. J. A. M. van Putten, G. J. M. Huiskamp, M. Zijlmans

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Objective: Removal of brain tissue showing high frequency oscillations (HFOs; ripples: 80-250 Hz and fast ripples: 250-500 Hz) in preresection electrocorticography (preECoG) in epilepsy patients seems a predictor of good surgical outcome. We analyzed occurrence and localization of HFOs in intra-operative preECoG and postresection electrocorticography (postECoG).

Methods: HFOs were automatically detected in one-minute epochs of intra-operative ECoG sampled at 2048 Hz of fourteen patients. Ripple, fast ripple, spike, ripples on a spike (RoS) and not on a spike (RnoS) rates were analyzed in pre- and postECoG for resected and nonresected electrodes.

Results: Ripple, spike and fast ripple rates decreased after resection. RnoS decreased less than RoS (74% vs. 83%; p = 0.01). Most fast ripples in preECoG were located in resected tissue. PostECoG fast ripples occurred in one patient with poor outcome. Patients with good outcome had relatively high postECoG RnoS rates, specifically in the sensorimotor cortex.

Conclusions: Our observations show that fast ripples in intra-operative ECoG, compared to ripples, may be a better biomarker for epileptogenicity. Further studies have to determine the relation between resection of epileptogenic tissue and physiological ripples generated by the sensorimotor cortex.

Significance: Fast ripples in intra-operative ECoG can help identify the epileptogenic zone, while ripples might also be physiological. (C) 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights.

Original languageEnglish
Pages (from-to)2212-2219
Number of pages8
JournalClinical Neurophysiology
Volume125
Issue number11
Publication statusPublished - Nov 2014

Keywords

  • Epilepsy surgery
  • Focal epilepsy
  • Electrocorticography
  • High frequency oscillations
  • TEMPORAL-LOBE EPILEPSY
  • INTRAOPERATIVE ELECTROCORTICOGRAPHY
  • PEDIATRIC EPILEPSY
  • FAST RIPPLES
  • SEIZURE REMISSION
  • RESECTION
  • CHILDREN
  • BRAIN
  • HZ
  • RECORDINGS

Fingerprint

Dive into the research topics of 'High frequency oscillations in intra- operative electrocorticography before and after epilepsy surgery'. Together they form a unique fingerprint.

Cite this