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

The purpose of this work was to compare the cortical localization of receptive speech using functional MRI (fMRI) and direct intraoperative electrical stimulation. 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. In all three subjects, similar, but nonidentical, cortical regions were identified as involved in receptive language function by fMRI and direct cortical stimulation mapping. 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.