Contribution of Single-pulse Electrical Stimulation Responses in the Localization of the Epileptogenic Zone During Stereo-electroencephalography
Abstract number :
1.478
Submission category :
3. Neurophysiology / 3C. Other Clinical EEG
Year :
2022
Submission ID :
2232943
Source :
www.aesnet.org
Presentation date :
12/3/2022 12:00:00 PM
Published date :
Nov 22, 2022, 05:28 AM
Authors :
Odile Feys, MD – ULB Hôpital Erasme; Vincent Wens, PhD – ULB Hôpital Erasme; Antonin Rovai, PhD – ULB Hôpital Erasme; Sophie Schuind, MD – ULB Hôpital Erasme; Estelle Rikir, MD, PhD – ULB Hôpital Erasme; Benjamin Legros, MD – ULB Hôpital Erasme; Xavier De Tiège, MD, PhD – ULB Hôpital Erasme; Nicolas Gaspard, MD, PhD – ULB Hôpital Erasme
This is a Late Breaking abstract
Rationale: Single-pulse electrical stimulation (SPES) during electrocorticography (ECoG) can elicit abnormal responses that might help delineate the epileptogenic zone (EZ). These include interictal spikes (Valentin et al, Brain, 2002), high-frequency oscillations (HFOs; Van’t Klooster et al, Brain, 2011), and abnormal cortico-cortical evoked potentials (CCEPs) that can be quantified with the connectivity index (CI; Yan et al, J Neurosurg, 2018)._x000D_
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In contrast, very little is known about the potential correlation between SPES responses elicited during stereo-EEG (SEEG) and the EZ (Buser et al, Electroencephalogr Clin Neurophysiol, 1983). SEEG provides different brain spatial sampling compared to ECoG, so SPES during SEEG may not contribute to a similar extent than ECoG to the delineation of the EZ. This study assesses if SPES responses (CCEPS features (CI, amplitude variations and latency), evoked spikes, HFOs), can contribute to the localization of temporal and extra-temporal EZ in SEEG._x000D_
Methods: Twenty-eight patients (14F, mean age: 26y, range: 8-54y, surgical resection: 18, follow-up at 1y: 11, Engel class 1 after 1y: 9 [81%]) underwent SPES (9mA, 300µs, biphasic pulse, 0.9Hz, 120s, 100 pulses) during 30 SEEGs (sampling rate: 1024Hz, mean electrodes: 14 (8-17), mean contacts: 159 (90-221), mean SPES number: 82 (9-217))._x000D_
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Averaged CCEPs were detected when exceeding a threshold determined with maximum-based permutation tests. The latency of each significant response, their amplitude variation (inter-trial standard deviation of the peak amplitude distribution), and the CI (as previously described by Yan et al, J Neurosurg, 2018) were assessed. Baseline and evoked spikes and HFOs were detected using a hidden Markov model (HMM; Van Ede et al, Trends Neurosci, 2018). The EZ was visually determined by experienced epileptologists blinded to SPES findings._x000D_
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CCEPs features, differences in spikes and HFOs rate between baseline and during SPES were compared for stimulations within the EZ and the non-involved zones (NIZ) using Wilcoxon tests (significance at p< 0.05). The significance of each feature was assessed at the patient level._x000D_
Neurophysiology