Functional MRI during word generation, using conventional equipment: a potential tool for language localization in the clinical environment.
Résumé
OBJECTIVE. To test the accuracy of bilateral language mapping using a standard clinical magnetic resonance (MR) imaging device during word generation. DESIGN. A study of normal volunteers. SETTING. Volunteers from the Washington, DC, area. PARTICIPANTS. Nine normal, right-handed, native English speakers (four women, five men, mean age 31 years). INTERVENTIONS. During four MR acquisition periods, subjects would alternately rest and silently generate words. Sagittal MR images covered the middle and inferior frontal gyri, insulae, and part of the temporal and parietal lobes bilaterally. MAIN OUTCOME MEASURES. (1) Anatomic maps of task-related signal changes obtained by comparing, in each voxel, the signal during word generation and rest periods, and (2) analysis of the time course of the signal. RESULTS. Maximum responses were in the left hemisphere, mainly in the frontal lobe (Broca's area, premotor cortex, and dorsolateral prefrontal cortex) but also in posterior regions such as Wernicke's area. In agreement with previous studies, some degree of task-related changes was present in a subset of the corresponding regions in the right hemisphere. CONCLUSION. Despite certain limitations, it is possible, using widely available MR equipment, to obtain results consistent with previous studies. The technique may have important implications for assessment of cognitive functions in patients with neurologic disorders in a clinical environment.