Elsevier

Clinical Neurophysiology

Volume 131, Issue 1, January 2020, Pages 225-234
Clinical Neurophysiology

Computational modelling in source space from scalp EEG to inform presurgical evaluation of epilepsy

https://doi.org/10.1016/j.clinph.2019.10.027Get rights and content
Under a Creative Commons license
open access

Highlights

  • Computational modelling is combined with scalp EEG to assess epilepsy lateralization.

  • Our approach proved useful in informing lateralization in 12 out of 15 individuals studied.

  • The framework proposed may be used to aid deciding where to implant intracranial electrodes.

Abstract

Objective

The effectiveness of intracranial electroencephalography (iEEG) to inform epilepsy surgery depends on where iEEG electrodes are implanted. This decision is informed by noninvasive recording modalities such as scalp EEG. Herein we propose a framework to interrogate scalp EEG and determine epilepsy lateralization to aid in electrode implantation.

Methods

We use eLORETA to map source activities from seizure epochs recorded from scalp EEG and consider 15 regions of interest (ROIs). Functional networks are then constructed using the phase-locking value and studied using a mathematical model. By removing different ROIs from the network and simulating their impact on the network’s ability to generate seizures in silico, the framework provides predictions of epilepsy lateralization. We consider 15 individuals from the EPILEPSIAE database and study a total of 62 seizures. Results were assessed by taking into account actual intracranial implantations and surgical outcome.

Results

The framework provided potentially useful information regarding epilepsy lateralization in 12 out of the 15 individuals (p=0.02, binomial test).

Conclusions

Our results show promise for the use of this framework to better interrogate scalp EEG to determine epilepsy lateralization.

Significance

The framework may aid clinicians in the decision process to define where to implant electrodes for intracranial monitoring.

Keywords

Epilepsy surgery
Source mapping
Scalp EEG
Neural mass model
Epileptogenic zone
Epilepsy lateralization

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1

Denotes an equal contribution as first author.