N E C van Klink1, M A Van't Klooster2, R Zelmann3, F S S Leijten2, C H Ferrier2, K P J Braun2, P C van Rijen2, M J A M van Putten4, G J M Huiskamp2, M Zijlmans5. 1. Brain Center Rudolf Magnus, Department of Neurology and Neurosurgery, University Medical Center Utrecht, The Netherlands; MIRA, Institute for Technical Medicine, University of Twente, The Netherlands. Electronic address: n.vanklink-2@umcutrecht.nl. 2. Brain Center Rudolf Magnus, Department of Neurology and Neurosurgery, University Medical Center Utrecht, The Netherlands. 3. Montreal Neurological Institute, McGill University, Canada. 4. MIRA, Institute for Technical Medicine, University of Twente, The Netherlands. 5. Brain Center Rudolf Magnus, Department of Neurology and Neurosurgery, University Medical Center Utrecht, The Netherlands; Epilepsy Institutes in the Netherlands, SEIN, Heemstede, The Netherlands.
Abstract
OBJECTIVE: Removal of brain tissue showing high frequency oscillations (HFOs; ripples: 80-250Hz and fast ripples: 250-500Hz) 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 2048Hz 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.
OBJECTIVE: Removal of brain tissue showing high frequency oscillations (HFOs; ripples: 80-250Hz and fast ripples: 250-500Hz) in preresection electrocorticography (preECoG) in epilepsypatients 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 2048Hz 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.
Authors: Birgit Frauscher; Fabrice Bartolomei; Katsuhiro Kobayashi; Jan Cimbalnik; Maryse A van 't Klooster; Stefan Rampp; Hiroshi Otsubo; Yvonne Höller; Joyce Y Wu; Eishi Asano; Jerome Engel; Philippe Kahane; Julia Jacobs; Jean Gotman Journal: Epilepsia Date: 2017-06-30 Impact factor: 5.864
Authors: Maryse A van 't Klooster; Frans S S Leijten; Geertjan Huiskamp; Hanneke E Ronner; Johannes C Baayen; Peter C van Rijen; Martinus J C Eijkemans; Kees P J Braun; Maeike Zijlmans Journal: Trials Date: 2015-09-23 Impact factor: 2.279
Authors: Anthony L Ritaccio; Justin Williams; Tim Denison; Brett L Foster; Philip A Starr; Aysegul Gunduz; Maeike Zijlmans; Gerwin Schalk Journal: Epilepsy Behav Date: 2016-10-24 Impact factor: 2.937
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