Multimodality language mapping in patients with left-hemispheric language dominance on Wada test

Area of Science:

• Neuroscience
• Neurosurgery
• Epileptology

Background:

• Accurate language mapping is crucial for neurosurgical planning in patients with left-hemispheric language dominance.
• The Wada test is a standard but invasive method for determining language lateralization.
• Electrocorticography (ECoG) offers potential for more precise intraoperative language mapping.

Purpose of the Study:

• To evaluate the utility of ECoG, specifically event-related gamma-oscillations, and direct cortical stimulation for identifying language-related brain sites.
• To compare the sensitivity of ECoG and stimulation in detecting language sites across different brain regions.

Main Methods:

• Studied 13 epileptic patients with left-hemispheric language dominance undergoing Wada testing.
• Language mapping was performed using ECoG to detect gamma-oscillations during an auditory-naming task and direct cortical stimulation via subdural electrodes.
• Language-related sites were defined based on significant gamma-augmentation or stimulation-induced changes.

Main Results:

• ECoG detected language-related sites more frequently than stimulation in the superior-temporal and inferior-frontal gyri (p < 0.05).
• Both methods detected language sites equally in the dorsolateral-premotor and inferior-Rolandic regions.
• Stimulation of ECoG-identified language sites elicited language symptoms more often (p < 0.00001).

Conclusions:

• Language-related gamma-oscillations detected by ECoG can serve as an alternative biomarker for language function.
• Measuring gamma-oscillations via ECoG is recommended for presurgical evaluation in epileptic patients.