Article
Preoperative navigated transcranial magnetic brain stimulation for tumors of the language cortex: clinical application and correlation with intraoperative direct cortical stimulation
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Published: | June 4, 2012 |
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Objective: Navigated transcranial magnetic brain stimulation (nTMS) is a newly evolving technique. For preoperative mapping of the central region good accuracy compared to direct cortical stimulation (DCS) and functional MRI (fMRI) was shown. However, repetitive nTMS can also inhibit specific brain regions and might therefore be suitable for mapping of language eloquent regions in the human brain.
Methods: Up to now, 12 patients underwent bilateral functional mapping of the language cortex by nTMS and object naming task prior to awake craniotomy. Data was then correlated with intraoperative awake language mapping by bipolar DCS and preoperative naming task fMRI.
Results: We were able to provoke reproducible speech impairment in every patient by nTMS and DCS. Determination of side dominance correlated well with fMRI except of one patient in which fMRI showed right-sided dominance despite clinical aphasia due to a left sided tumor in the inferior frontal gyrus. In general, preoperative language mapping by nTMS showed a high sensitivity but low specifity compared to intraoperative DCS, so far.
Conclusions: Repetitive nTMS is feasible for presurgical language mapping. All nTMS negative regions correlated well with DCS negative regions thus giving us a reliable negative map of language eloquent regions preoperatively. Moreover, nTMS seems already superior to fMRI when used for language dominance testing.