128-channel EEG source imaging in epilepsy: clinical yield and localization precision

Area of Science:

• Neuroscience
• Medical Imaging
• Epileptology

Background:

• Intractable epilepsy requires precise localization of epileptogenic zones for effective presurgical planning.
• Current neuroimaging methods may have limitations in speed, cost, or precision.

Purpose of the Study:

• To assess the feasibility, clinical utility, and localization accuracy of high-resolution EEG source imaging for interictal epileptic activity.
• To evaluate the precision of this technique in relation to surgical resection outcomes.

Main Methods:

• A 128-channel EEG recording was performed on 44 patients with intractable epilepsy undergoing presurgical evaluation.
• A standardized, gray matter-constrained source imaging procedure was applied to averaged interictal spikes.
• Localization precision was assessed by comparing source imaging results with identified epileptogenic areas and surgical resection sites.

Main Results:

• EEG source imaging correctly localized the epileptogenic area in 93.7% (30/32) of patients with focal epilepsy identified by presurgical workup.
• In surgically treated patients, the source imaging maximum was within the resected area in 79% (19/24) of cases.
• Minor inaccuracies were attributed to simplifications for speed and standardization.

Conclusions:

• High-resolution interictal EEG source imaging is a valuable, noninvasive functional neuroimaging technique for epilepsy.
• The method demonstrates high accuracy and sublobar precision, making it suitable for clinical practice.
• Its speed, ease of use, flexibility, and low cost further support its clinical adoption.