Defining epileptogenic foci: past, present, future

Area of Science:

• Neuroscience
• Medical Imaging
• Epileptology

Background:

• Traditionally, electroencephalography (EEG) localizes epileptogenic foci by identifying negative field maxima.
• The complete voltage field topography, including positive and negative maxima, is crucial for accurate focus characterization.

Discussion:

• Mathematical source models, like equivalent dipoles, enable 3D visualization and precise localization of epileptogenic foci.
• Utilizing additional electrodes, especially on the lower scalp, and accurate electrode placement enhances localization accuracy.
• Realistic head models derived from MRI scans improve upon simplistic spherical models, reducing localization errors.

Key Insights:

• The spatial characteristics of cortex-generating epileptiform discharges directly correlate with scalp-recorded voltage fields.
• Equivalent dipole models can pinpoint epileptogenic foci with sub-lobar accuracy.
• Integrating EEG topography and source models with patient-specific MRI data transforms EEG into a high-resolution functional imaging tool.

Outlook:

• Future research should focus on refining mathematical models and optimizing electrode configurations for even greater precision.
• Developing advanced co-registration techniques will further enhance EEG's role in presurgical epilepsy evaluation.
• This integrated approach promises to significantly improve the definition and surgical planning for patients with epilepsy.