Stereo-Electroencephalography-Recorded Interictal Epileptiform Discharges: Activation Pattern and Its Relationship...

Area of Science:

• Neuroscience
• Epileptology
• Neurosurgery

Background:

• Drug-resistant epilepsy often requires stereo-electroencephalography (SEEG) for surgical evaluation.
• Identifying the seizure onset zone (SOZ) is key, but the role of interictal epileptiform discharges (IEDs) is unclear.

Purpose of the Study:

• To investigate the clinical significance of IEDs in relation to the SOZ.
• To determine if IED patterns correlate with epilepsy characteristics and surgical outcomes.

Main Methods:

• Retrospective analysis of SEEG data from adult patients (2019-2022).
• Classification of IEDs as leading (within SOZ) or distant (outside SOZ).
• Correlation of distant spike subregion count with epilepsy type, duration, and surgical outcome (Engel score).

Main Results:

• Leading spikes activated within 24 hours of SEEG in 87% of patients.
• No activation pattern observed for distant spikes.
• A higher number of subregions generating distant spikes was significantly associated with poor surgical outcomes (p=0.002).

Conclusions:

• Early activation of SOZ-involved IEDs may help identify the irritative zone.
• Widespread distant IEDs correlate with unfavorable surgical results, warranting further investigation in larger prospective studies.