Interictal and ictal dipole modelling in patients with refractory partial epilepsy

Area of Science:

• Neurology
• Neurophysiology
• Epileptology

Background:

• Refractory partial epilepsy poses significant diagnostic challenges, often requiring invasive monitoring for precise localization.
• Accurate identification of the epileptogenic zone is crucial for successful surgical outcomes.

Purpose of the Study:

• To evaluate the utility of voltage topography and spatiotemporal dipole mapping in localizing seizure onset in patients with refractory partial epilepsy.
• To correlate interictal and ictal discharge patterns with lesion location and intracranial EEG findings.

Main Methods:

• Neuroimaging (CAT, MRI) and video-EEG monitoring were performed on 15 patients with refractory partial epilepsy.
• Intracranial EEG monitoring was used in a subset of patients.
• Voltage topography and spatiotemporal dipole mapping were applied to interictal and ictal epileptic discharges.

Main Results:

• Two distinct dipole types were identified, correlating with lesion location (medial temporal vs. extratemporal).
• Medial temporal lobe lesions showed specific voltage field and dipole characteristics.
• Extratemporal lesions exhibited more diffuse fields and less stable dipoles.
• Dipole modeling of early ictal discharges showed strong concordance with interictal findings.

Conclusions:

• Interictal spike voltage topography and dipole mapping offer reliable supplementary information for localizing epileptic sources in refractory partial epilepsy.
• The findings suggest potential for non-invasive localization, guiding surgical candidacy and planning.
• Further validation in larger cohorts with intracranial EEG is warranted.