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Iimura Y, Jones K, Hattori K, Okazawa Y, Noda A, Hoashi K, Nonoda Y, Asano E, Akiyama T, Go C, Ochi A, Snead OC, Donner EJ, Rutka JT, Drake JM, Otsubo H. Epileptogenic high-frequency oscillations skip the motor area in children with multilobar drug-resistant epilepsy. Clin Neurophysiol 2017; 128:1197-1205. [PMID: 28521267 DOI: 10.1016/j.clinph.2017.03.031] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 03/07/2017] [Accepted: 03/13/2017] [Indexed: 11/18/2022]
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).
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Affiliation(s)
- Yasushi Iimura
- Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Kevin Jones
- Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Kyoko Hattori
- Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Yushi Okazawa
- Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Atsuko Noda
- Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Kana Hoashi
- Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Yutaka Nonoda
- Pediatrics and Neurology, Children's Hospital of Michigan, Wayne State University, Detroit, MI, USA
| | - Eishi Asano
- Pediatrics and Neurology, Children's Hospital of Michigan, Wayne State University, Detroit, MI, USA
| | - Tomoyuki Akiyama
- Department of Child Neurology, Okayama University Hospital, Okayama, Japan
| | - Cristina Go
- Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Ayako Ochi
- Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - O Carter Snead
- Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Elizabeth J Donner
- Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - James T Rutka
- Division of Neurosurgery, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - James M Drake
- Division of Neurosurgery, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Hiroshi Otsubo
- Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada.
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