Electrical Source Imaging in Stereoelectroencephalography: A Proof-of-Concept Study

Area of Science:

• Neuroscience
• Medical Imaging
• Epileptology

Background:

• Electrical Source Imaging (ESI) traditionally uses scalp EEG but shows potential for intracerebral recordings.
• Stereoelectroencephalography (SEEG) provides direct intracerebral data, offering a unique opportunity to evaluate ESI.
• Accurate source localization is crucial for understanding brain function and treating neurological disorders like epilepsy.

Purpose of the Study:

• To systematically evaluate the source localization accuracy of ESI when applied to SEEG data.
• To compare the performance of different inverse solution methods for ESI with SEEG.
• To determine the most effective ESI method for intracerebral source localization.

Main Methods:

• Three inverse solution methods (sLORETA, MNE, dSPM) were compared.
• Localization accuracy was assessed by measuring the distance between the stimulation site and the estimated source peak.
• The study involved 12 subjects undergoing SEEG, localizing stimulation artifacts.

Main Results:

• Standardized low-resolution electromagnetic tomography (sLORETA) exhibited the highest localization accuracy.
• Mean localization error was 11.65 mm for single stimuli, improving to 9.28 mm when averaging 10 stimuli.
• Subcentimeter accuracy was achieved in 77.5% of averaged trials, with sLORETA maintaining accuracy even with increasing distance from SEEG contacts.

Conclusions:

• ESI is a viable method for accurate source localization using SEEG data.
• sLORETA proved to be the most effective inverse solution method tested.
• This approach can enhance spatial interpretability in complex epilepsy cases, especially with limited spatial sampling.