Epileptogenic high-frequency oscillations skip the motor area in children with multilobar drug-resistant epilepsy.

Abstract

OBJECTIVE:

Subtotal hemispherectomy involves the resection of multiple lobes in children with drug-resistant epilepsy, skipping the motor area (MA). We determined epileptogenicity using the occurrence rate (OR) of high-frequency oscillations (HFOs) and the modulation index (MI), demonstrating strength of coupling between HFO and slow wave. We hypothesized that epileptogenicity increased over the multiple lobes but skipped the MA.

METHODS:

We analyzed 23 children (14 subtotal hemispherectomy; 9 multilobar resections). Scalp video-EEG and magnetoencephalography were performed before surgery. We analyzed the OR(HFO) and MI(5 phases=0.5-8 Hz) on electrodes of total area, resection areas, and MA. We compared the data between good [International League Against Epilepsy (ILAE) class I-II] and poor (III-VI) seizure outcome groups.

RESULTS:

ILAE class Ia outcome was achieved in 18 children. Among the MI(5 phases) in the resection areas, MI(3-4 Hz) was the highest. The OR(HFO) and MI(3-4 Hz) in both total area and resection areas were significantly higher in the good seizure outcome group than in the poor outcome group. The OR(HFO) and MI(3-4 Hz) in resection areas were significantly higher than in the MA.

CONCLUSIONS:

Our patients with multilobar drug-resistant epilepsy showed evidence of multifocal epileptogenicity that specifically skipped the MA.

SIGNIFICANCE:

This is the first study demonstrating that the electrophysiological phenotype of multifocal epilepsy specifically skips the MA using OR(HFO) and MI(3-4 Hz).

• Authors: Yasushi Iimura, Kevin Jones, Kyoko Hattori, Yushi Okazawa, Atsuko Noda, Kana Hoashi, Yutaka Nonoda, Eishi Asano, Tomoyuki Akiyama, Cristina Go, Ayako Ochi, O Carter Snead 3rd, Elizabeth J Donner, James T Rutka, James M Drake, Hiroshi Otsubo
• Journal: Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology (Clin Neurophysiol) Vol. 128 Issue 7 Pg. 1197-1205 (07 2017) ISSN: 1872-8952 [Electronic] Netherlands
• PMID: 28521267 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

Topics

• Adolescent
• Brain Mapping (methods)
• Child
• Child, Preschool
• Drug Resistant Epilepsy (diagnosis, physiopathology, surgery)
• Electroencephalography (methods)
• Female
• Humans
• Infant
• Magnetoencephalography (methods)
• Male
• Motor Cortex (physiology)
• Retrospective Studies
• Video Recording (methods)