nTMS Language Mapping: Basic Principles and Clinical Use

The method nTMS has proven useful for the preoperative workup of brain tumor and epilepsy surgery in localization of the motor cortical areas. We have developed a videoed nrTMS setup combined with object naming to localize language-related cortical areas in preoperative planning. The method has high sensitivity and predicts well the cortical areas not involved in language in comparison with the results of DES during object naming in patients going through awake craniotomy. Nevertheless, the optimal stimulus parameters to achieve the most precise preoperative information are still searched for. The method may also have potential for plastic cortical change follow-up due to tumor growth or after tumor removal. No harmful side effects have occurred in the control or patient studies. Though the first reports using only nrTMS language mapping to localize the cortical language representations are favorable, DES during awake craniotomy is still the gold standard of cortical language-related areas’ functional localization.