Incidence and linguistic quality of speech errors: a comparison of preoperative transcranial magnetic stimulation and intraoperative direct cortex stimulation.

Objective: Given the interindividual variance of functional language anatomy, risk prediction based merely on anatomical data is insufficient in language area-related brain tumor surgery, suggesting the need for direct cortical and subcortical mapping during awake surgery. Reliable, noninvasive preoperative methods of language localization hold the potential for reducing the necessity for awake procedures and may improve patient counseling and surgical planning. Repetitive navigated transcranial magnetic stimulation (rnTMS) is an evolving tool for localizing language-eloquent areas.