CORTICAL MAPPING OF LANGUAGE AND SPEECH F UNCTIONS DURING SURGERY FORSPACE-OCCUPYING LESIONS UNDER LOCAL-ANESTHESIA

We report on 30 cases where we have used cortical stimulation mapping to define the areas representing sensorimotor, language and speech fun ctions under local anesthesia to facilitate resection of space-occupyi ng lesions near these areas. Under the simplistic concept that Broca's area lies in the frontal operculum (inferior frontal gyrus) and that Wernicke's area is located in the posterior perisylvian area (superior temporal, angular and supramarginal gyri), we found language and spee ch function to be represented outside these areas in up to 4 stimulati on sites of 15 patients. The results of cortical stimulation mapping w ere therefore essential to decide on the optimal access route to the l esions that were located subcortically and on the optimal resection pl ane in gliomas. After the limits of these areas and of the lesions had been established with stimulation mapping and with intrasurgical micr oscopic smear preparations, respectively lesions were safely removed u nder continuous monitoring of sensorimotor, language and speech functi on. Immediately after surgery we encountered language and speech defic its in 9 patients (30%), which resolved completely in 5 and inclomplet ely in 4 instances. Thus, language functions were normal in 26 patient s (87%) at the end of the follow-up period. It is concluded that use o f this technique allows safe and extensive resection of lesions that w ould otherwise have been considered hazardous to remove or inexcisable .