Comparison of fMRI and intraoperative direct cortical stimulation in localization of receptive language areas

Purpose: The purpose of this work was to compare the cortical localization of receptive speech using functional MRI (fMRI) and direct intraoperative electrical stimulation. Method: Three strongly right-handed patients with primary neoplasms of the left parasylvian region underwent fMRI while subjected to a passive listening task designed to activate receptive language areas. All three subjects then underwent awake intraoperative language mapping using direct electrical stimulation of the cortex. Results: In all three subjects, similar, but nonidentical, cortical regions were identified as involved in receptive language function by fMRI and direct cortical stimulation mapping. Conclusion: fMRI provides excellent receptive language mapping, but its results must be interpreted with caution due to conceptual and technical differences from direct cortical stimulation mapping.