Localizing epileptogenic zones with high-frequency oscillations and directed connectivity

Area of Science:

• Neuroscience
• Medical Imaging
• Signal Processing

Background:

• Precise localization of the epileptogenic zone (EZ) is critical for successful epilepsy surgery.
• Current methods struggle with detecting subtle seizure onset patterns in neural signals.

Purpose of the Study:

• To introduce a novel measure, the connectivity high-frequency epileptogenicity index (cHFEI), for quantifying epileptogenicity.
• To address limitations of existing methods in detecting slow onset seizure patterns.

Main Methods:

• The cHFEI method integrates directed connectivity and high-frequency oscillations (HFOs).
• Applied to stereoelectroencephalography (SEEG) data from 49 seizures in 20 patients.
• Performance evaluated using accuracy, sensitivity, precision, confusion matrix, and ROC curve analysis against visually identified EZs.

Main Results:

• cHFEI effectively differentiated seizure onset regions from propagation networks.
• cHFEI demonstrated superior performance in EZ estimation compared to existing methods.
• Achieved an average area under the ROC curve of 0.88 and an accuracy of 0.85.

Conclusions:

• cHFEI robustly characterizes the EZ across diverse seizure onset patterns.
• The cHFEI method shows significant potential for application in epilepsy treatment planning.