Intraoperative speech mapping in 17 bilingual patients undergoing resection of a mass lesion

Language mapping has been reported previously for bilingual patients undergoing cortical resection of an epileptic focus that may have developed early in life. In this setting, the cortical organization of language may have been affected by the effects of having a seizure focus established early in life. Adults presenting with a primary brain tumor offer a different opportunity to study bilingual cortical representation of language sites, because presumably the brain has been unaffected by epilepsy during the first decade of life or beyond. In this analysis, we present the results for 17 bilingual patients who underwent speech mapping as part of the surgical procedure to remove a mass lesion.

The localization of cortical sites essential for language was assessed in 17 patients undergoing resection of a mass lesion. Stimulation mapping was performed in each language by use of an object-naming task. A site thought to be essential for naming was any site, in either language, in which interruption of naming (anomia) occurred in at least two-thirds of the stimulations at that site.

A site essential for naming was identified in the exposed cortex for 5 of 17 patients, whereas no essential site was found for 12 patients, presumably because of a limited surgical exposure. For the patients in whom a site essential for naming was identified, two patients displayed anomia in both languages, two others had anomia in only one language, and one showed anomia in one language but only hesitation of naming in the other language.

Although no site was identified in the majority of the patients, those individuals in whom a site was identified demonstrate that bilingual patients undergoing tumor resection should be mapped for all languages regardless of patient age before it is decided which cortical and subcortical areas are safe to remove.