Interictal Electrical Source Imaging

Area of Science:

• Neuroscience
• Medical Imaging
• Computational Modeling

Background:

• Epilepsy surgery requires precise localization of seizure onset zones.
• Pharmacoresistant focal epilepsies necessitate advanced diagnostic tools for surgical candidacy assessment.
• Interictal electrical source imaging (ESI) analyzes non-seizure brain activity to identify epileptic neuronal generators.

Purpose of the Study:

• To provide an overview of the application and clinical value of interictal ESI in patients with pharmacoresistant focal epilepsies.
• To discuss the neurophysiological constraints and technical considerations of interictal ESI.
• To explore novel markers for improving interictal source analysis.

Main Methods:

• Utilizes computational models incorporating individual patient's anatomic and neuronal characteristics.
• Applies electrical source imaging to electroencephalography (EEG) data recorded between seizures.
• Considers high-density EEG recordings for enhanced accuracy, but also demonstrates value with limited electrode coverage.

Main Results:

• Interictal ESI demonstrates diagnostic performance on par with established neuroimaging techniques like MRI, PET, and SPECT.
• The method provides valuable localization information even with limited EEG electrode coverage.
• Novel oscillatory markers and frequency coupling/connectivity integration show potential for future accuracy improvements.

Conclusions:

• Interictal ESI is a valuable tool for evaluating patients with pharmacoresistant focal epilepsies for epilepsy surgery.
• Its accuracy can be further enhanced by high-density recordings and novel analytical approaches.
• Integration into clinical routine is feasible and offers significant diagnostic utility.