Language mapping using high gamma electrocorticography, fMRI, and TMS versus electrocortical stimulation

Area of Science:

• Neuroscience
• Neurosurgery
• Epilepsy Research

Background:

• Accurate presurgical language mapping is crucial for patients undergoing epilepsy surgery.
• Cortical stimulation mapping (CSM) is a standard but invasive method for identifying language areas.

Purpose of the Study:

• To compare the efficacy of high gamma electrocorticography (hgECoG), functional magnetic resonance imaging (fMRI), and transcranial magnetic stimulation (TMS) for language cortex localization.
• To evaluate these methods against the reference standard of CSM.

Main Methods:

• Language mapping was performed in nine epilepsy patients using CSM, hgECoG, fMRI, and TMS.
• Sensitivity, specificity, and receiver operating characteristic (ROC) analyses were used to compare the techniques, with CSM as the reference.

Main Results:

• hgECoG demonstrated high sensitivity (100%) and specificity (85%), with an average ROC area of 0.98.
• fMRI showed 50% sensitivity and 80% specificity (ROC area 0.76), while TMS had 67% sensitivity and 66% specificity (ROC area 0.68).
• All tested methods successfully identified language processing areas.

Conclusions:

• hgECoG, fMRI, and TMS are valuable tools for presurgical language mapping, showing considerable concordance with CSM.
• These techniques provide supplementary information and can serve as alternatives to CSM when it is impractical.