Localization of stereo-electroencephalography signals using a finite difference complete electrode model

Area of Science:

• Neurosurgery
• Epileptology
• Biomedical Engineering
• Computational Neuroscience

Background:

• Epilepsy surgery aims to resect seizure onset zones in refractory cases.
• Stereo-electroencephalography (sEEG) offers precise but spatially ambiguous electrophysiological data.
• Accurate 3D source localization is crucial for interpreting sEEG and guiding surgical intervention.

Purpose of the Study:

• To develop and validate a finite difference approach for 3D source localization using sEEG.
• To improve the association of sEEG-derived seizure onsets with specific cortical regions.
• To enhance the accuracy of brain electrical activity modeling for epilepsy surgery.

Main Methods:

• A finite difference approach was employed, incorporating a complete electrode model for sEEG.
• The model accounted for electrode contact impedance and physical dimensions.
• The method was applied to MRI and CT data from an epilepsy patient with intractable seizures.

Main Results:

• The 3D source localization successfully reconstructed activity from multiple ictal spike types.
• The identified seizure focus was precisely located in the occipital lobe.
• The localized focus was fully contained within the surgically resected region.

Conclusions:

• The developed finite difference model accurately localizes seizure foci from sEEG data.
• This method enhances the interpretation of sEEG, aiding neurosurgeons in precise targeting.
• The findings support the clinical utility of advanced source localization for epilepsy surgery outcomes.