An evaluation of kurtosis beamforming in magnetoencephalography to localize the epileptogenic zone in drug resistant epilepsy patients

Michael B H Hall; Ida A Nissen; Elisabeth C W van Straaten; Paul L Furlong; Caroline Witton; Elaine Foley; Stefano Seri; Arjan Hillebrand

doi:10.1016/j.clinph.2017.12.040

An evaluation of kurtosis beamforming in magnetoencephalography to localize the epileptogenic zone in drug resistant epilepsy patients

Michael B H Hall, Ida A Nissen, Elisabeth C W van Straaten, Paul L Furlong, Caroline Witton, Elaine Foley, Stefano Seri, Arjan Hillebrand

Research output: Contribution to journal › Article › peer-review

Abstract

OBJECTIVE: Kurtosis beamforming is a useful technique for analysing magnetoencephalograpy (MEG) data containing epileptic spikes. However, the implementation varies and few studies measure concordance with subsequently resected areas. We evaluated kurtosis beamforming as a means of localizing spikes in drug-resistant epilepsy patients.

METHODS: We retrospectively applied kurtosis beamforming to MEG recordings of 22 epilepsy patients that had previously been analysed using equivalent current dipole (ECD) fitting. Virtual electrodes were placed in the kurtosis volumetric peaks and visually inspected to select a candidate source. The candidate sources were compared to the ECD localizations and resection areas.

RESULTS: The kurtosis beamformer produced interpretable localizations in 18/22 patients, of which the candidate source coincided with the resection lobe in 9/13 seizure-free patients and in 3/5 patients with persistent seizures. The sublobar accuracy of the kurtosis beamformer with respect to the resection zone was higher than ECD (56% and 50%, respectively), however, ECD resulted in a higher lobar accuracy (75%, 67%).

CONCLUSIONS: Kurtosis beamforming may provide additional value when spikes are not clearly discernible on the sensors and support ECD localizations when dipoles are scattered.

SIGNIFICANCE: Kurtosis beamforming should be integrated with existing clinical protocols to assist in localizing the epileptogenic zone.

Original language	English
Pages (from-to)	1221-1229
Number of pages	9
Journal	Clinical Neurophysiology
Volume	129
Issue number	6
Early online date	9 Mar 2018
DOIs	https://doi.org/10.1016/j.clinph.2017.12.040
Publication status	Published - 1 Jun 2018

Bibliographical note

© 2018, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International

Funding: Funding: Dutch Epilepsy Foundation (project 14-16) and an MRC UK MEG Partnership Grant, MR/K005464/1 and an MRC Doctoral Training Grant, MR/K501086/1.

Keywords

Adult
Brain/diagnostic imaging
Brain Mapping
Drug Resistant Epilepsy/diagnostic imaging
Humans
Magnetoencephalography
Male
Middle Aged
Neuroimaging/methods
Retrospective Studies
Seizures/diagnostic imaging
Young Adult

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10.1016/j.clinph.2017.12.040

An evaluation of kurtosis beamforming in magnetoencephalography to localize
© 2018, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
Accepted author manuscript, 1 MBLicence: CC BY-NC-ND 3.0

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title = "An evaluation of kurtosis beamforming in magnetoencephalography to localize the epileptogenic zone in drug resistant epilepsy patients",

abstract = "OBJECTIVE: Kurtosis beamforming is a useful technique for analysing magnetoencephalograpy (MEG) data containing epileptic spikes. However, the implementation varies and few studies measure concordance with subsequently resected areas. We evaluated kurtosis beamforming as a means of localizing spikes in drug-resistant epilepsy patients.METHODS: We retrospectively applied kurtosis beamforming to MEG recordings of 22 epilepsy patients that had previously been analysed using equivalent current dipole (ECD) fitting. Virtual electrodes were placed in the kurtosis volumetric peaks and visually inspected to select a candidate source. The candidate sources were compared to the ECD localizations and resection areas.RESULTS: The kurtosis beamformer produced interpretable localizations in 18/22 patients, of which the candidate source coincided with the resection lobe in 9/13 seizure-free patients and in 3/5 patients with persistent seizures. The sublobar accuracy of the kurtosis beamformer with respect to the resection zone was higher than ECD (56% and 50%, respectively), however, ECD resulted in a higher lobar accuracy (75%, 67%).CONCLUSIONS: Kurtosis beamforming may provide additional value when spikes are not clearly discernible on the sensors and support ECD localizations when dipoles are scattered.SIGNIFICANCE: Kurtosis beamforming should be integrated with existing clinical protocols to assist in localizing the epileptogenic zone.",

keywords = "Adult, Brain/diagnostic imaging, Brain Mapping, Drug Resistant Epilepsy/diagnostic imaging, Humans, Magnetoencephalography, Male, Middle Aged, Neuroimaging/methods, Retrospective Studies, Seizures/diagnostic imaging, Young Adult",

author = "Hall, {Michael B H} and Nissen, {Ida A} and {van Straaten}, {Elisabeth C W} and Furlong, {Paul L} and Caroline Witton and Elaine Foley and Stefano Seri and Arjan Hillebrand",

note = "{\textcopyright} 2018, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Funding: Funding: Dutch Epilepsy Foundation (project 14-16) and an MRC UK MEG Partnership Grant, MR/K005464/1 and an MRC Doctoral Training Grant, MR/K501086/1.",

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doi = "10.1016/j.clinph.2017.12.040",

language = "English",

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T1 - An evaluation of kurtosis beamforming in magnetoencephalography to localize the epileptogenic zone in drug resistant epilepsy patients

AU - Hall, Michael B H

AU - Nissen, Ida A

AU - van Straaten, Elisabeth C W

AU - Furlong, Paul L

AU - Witton, Caroline

AU - Foley, Elaine

AU - Seri, Stefano

AU - Hillebrand, Arjan

N1 - © 2018, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Funding: Funding: Dutch Epilepsy Foundation (project 14-16) and an MRC UK MEG Partnership Grant, MR/K005464/1 and an MRC Doctoral Training Grant, MR/K501086/1.

PY - 2018/6/1

Y1 - 2018/6/1

N2 - OBJECTIVE: Kurtosis beamforming is a useful technique for analysing magnetoencephalograpy (MEG) data containing epileptic spikes. However, the implementation varies and few studies measure concordance with subsequently resected areas. We evaluated kurtosis beamforming as a means of localizing spikes in drug-resistant epilepsy patients.METHODS: We retrospectively applied kurtosis beamforming to MEG recordings of 22 epilepsy patients that had previously been analysed using equivalent current dipole (ECD) fitting. Virtual electrodes were placed in the kurtosis volumetric peaks and visually inspected to select a candidate source. The candidate sources were compared to the ECD localizations and resection areas.RESULTS: The kurtosis beamformer produced interpretable localizations in 18/22 patients, of which the candidate source coincided with the resection lobe in 9/13 seizure-free patients and in 3/5 patients with persistent seizures. The sublobar accuracy of the kurtosis beamformer with respect to the resection zone was higher than ECD (56% and 50%, respectively), however, ECD resulted in a higher lobar accuracy (75%, 67%).CONCLUSIONS: Kurtosis beamforming may provide additional value when spikes are not clearly discernible on the sensors and support ECD localizations when dipoles are scattered.SIGNIFICANCE: Kurtosis beamforming should be integrated with existing clinical protocols to assist in localizing the epileptogenic zone.

AB - OBJECTIVE: Kurtosis beamforming is a useful technique for analysing magnetoencephalograpy (MEG) data containing epileptic spikes. However, the implementation varies and few studies measure concordance with subsequently resected areas. We evaluated kurtosis beamforming as a means of localizing spikes in drug-resistant epilepsy patients.METHODS: We retrospectively applied kurtosis beamforming to MEG recordings of 22 epilepsy patients that had previously been analysed using equivalent current dipole (ECD) fitting. Virtual electrodes were placed in the kurtosis volumetric peaks and visually inspected to select a candidate source. The candidate sources were compared to the ECD localizations and resection areas.RESULTS: The kurtosis beamformer produced interpretable localizations in 18/22 patients, of which the candidate source coincided with the resection lobe in 9/13 seizure-free patients and in 3/5 patients with persistent seizures. The sublobar accuracy of the kurtosis beamformer with respect to the resection zone was higher than ECD (56% and 50%, respectively), however, ECD resulted in a higher lobar accuracy (75%, 67%).CONCLUSIONS: Kurtosis beamforming may provide additional value when spikes are not clearly discernible on the sensors and support ECD localizations when dipoles are scattered.SIGNIFICANCE: Kurtosis beamforming should be integrated with existing clinical protocols to assist in localizing the epileptogenic zone.

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KW - Brain/diagnostic imaging

KW - Brain Mapping

KW - Drug Resistant Epilepsy/diagnostic imaging

KW - Humans

KW - Magnetoencephalography

KW - Male

KW - Middle Aged

KW - Neuroimaging/methods

KW - Retrospective Studies

KW - Seizures/diagnostic imaging

KW - Young Adult

UR - http://linkinghub.elsevier.com/retrieve/pii/S138824571830230X

U2 - 10.1016/j.clinph.2017.12.040

DO - 10.1016/j.clinph.2017.12.040

M3 - Article

C2 - 29660580

SN - 1388-2457

VL - 129

SP - 1221

EP - 1229

JO - Clinical Neurophysiology

JF - Clinical Neurophysiology

IS - 6

ER -

An evaluation of kurtosis beamforming in magnetoencephalography to localize the epileptogenic zone in drug resistant epilepsy patients

Abstract

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Keywords

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