Page 215 - MEGIN Book Of Abstracts - 2023

of Bioengineering, University of Texas at Arlington, Arlington, versely, scalp ripples-alone are most likely generated by
Texas non-epileptogenic areas.

OBJECTIVE To assess the ability of high-density Elec- Annals of clinical and translational neurology (2020), Vol.
troencephalography (HD-EEG) and magnetoencepha- 7, No. 3 (32096612) (22 citations)
lography (MEG) to localize interictal ripples, distinguish
between ripples co-occurring with spikes (ripples-on-
spike) and independent from spikes (ripples-alone), Somatosensory evoked fields predict response to
and evaluate their localizing value as biomarkers of vagus nerve stimulation (2020)
epileptogenicity in children with medically refractory
epilepsy. Mithani, Karim; Wong, Simeon M; Mikhail, Mirriam;
Pourmotabbed, Haatef; Pang, Elizabeth; Sharma, Roy;
METHODS We retrospectively studied 20 children who Yau, Ivanna; Ochi, Ayako; Otsubo, Hiroshi; Snead, O
underwent epilepsy surgery. We identified ripples on Carter; Donner, Elizabeth; Go, Cristina; Widjaja, Elysa;
HD-EEG and MEG data, localized their generators, and Babajani-Feremi, Abbas; Ibrahim, George M
compared them with intracranial EEG (icEEG) ripples.
When ripples and spikes co-occurred, we performed Faculty of Medicine, University of Toronto, Toronto, Canada;
source imaging distinctly on the data above 80 Hz (to Institute of Biomaterials and Biomedical Engineering, Univer-
localize ripples) and below 70 Hz (to localize spikes). We sity of Toronto, Toronto, Canada; Department of Pediatrics,
assessed whether missed resection of ripple sources University of Tennessee Health Science Center, Memphis, TN,
predicted poor outcome, separately for ripples-on- USA; Neuroscience Institute, Le Bonheur Children's Hospital,
spikes and ripples-alone. Similarly, predictive value of Memphis, TN, USA; Division of Neurology, Hospital for Sick
spikes was calculated. Children, Toronto, Canada; Division of Neurology, Hospital for
Sick Children, Toronto, Canada; Institute of Medical Science,
RESULTS We observed scalp ripples in 16 patients (10 University of Toronto, Toronto, Canada; Institute of Medical
good outcome). Ripple sources were highly concor- Science, University of Toronto, Toronto, Canada; Department
dant to the icEEG ripples (HD-EEG concordance: 79%; of Diagnostic Imaging, Hospital for Sick Children, Toronto,
MEG: 83%). When ripples and spikes co-occurred, Canada; Department of Pediatrics, University of Tennessee
their sources were spatially distinct in 83-84% of the Health Science Center, Memphis, TN, USA; Department of
cases. Removing the sources of ripples-on-spikes pre- Anatomy and Neurobiology, University of Tennessee Health
dicted good outcome with 90% accuracy for HD-EEG Science Center, Memphis, TN, USA; Neuroscience Institute,
(P = 0.008) and 86% for MEG (P = 0.044). Conversely, Le Bonheur Children's Hospital, Memphis, TN, USA; Institute
removing ripples-alone did not predict outcome. Re- of Biomaterials and Biomedical Engineering, University of
section of spike sources (generated at the same time as Toronto, Toronto, Canada; Institute of Medical Science, Uni-
ripples) predicted good outcome for HD-EEG (P = 0.036; versity of Toronto, Toronto, Canada; Division of Neurosurgery,
accuracy = 87%), while did not reach significance for Hospital for Sick Children, Department of Surgery, University
MEG (P = 0.1; accuracy = 80%). of Toronto, Toronto, Canada. Electronic address: george.
[email protected]
INTERPRETATION HD-EEG and MEG localize interictal
ripples with high precision in children with refractory ABSTRACT There is an unmet need to develop robust
epilepsy. Scalp ripples-on-spikes are prognostic, nonin- predictive algorithms to preoperatively identify pediat-
vasive biomarkers of epileptogenicity, since removing ric epilepsy patients who will respond to vagus nerve
their cortical generators predicts good outcome. Con- stimulation (VNS). Given the similarity in the neural
circuitry between vagus and median nerve afferent
projections to the primary somatosensory cortex, the
current study hypothesized that median nerve somato-

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