INTRAOPERATIVE LANGUAGE LOCALIZATIONIN MULTILINGUAL PATIENTS WITH GLIOMAS

Abstract

OBJECTIVE Intraoperative localization of speech is problematic in patients that are fluent with different languages. Previous studies have generated various results depending on the series of patients studied, the type of language and the sensitivity of the tasks applied. It is not clear if languages are mediated by multiple and separate cortical areas, or shared by common areas. Globally considered, previous studies recommended performing a multiple intra-operative mapping for all the languages the patient is fluent for. Aim of this work was to study the feasibility of performing an intra-operative multiple language mapping in a group of multilingual patients with a glioma undergoing awake craniotomy for tumor removal, to describe the intraoperative cortical and subcortical findings in the area of craniotomy, with the final goal to maximally preserve their functional language. METHODS Seven late highly proficient multilingual patients with a left frontal glioma were submitted pre-operatively to a battery of tests to evaluate oral language production, comprehension, and repetition. Each language was tested serially starting from the first acquired language. Items which were correctly named during these tests were used to build personalized blocks to be used intraoperatively. Language mapping was undertaken during awake craniotomies, by the use of a Ojemann cortical stimulator during counting and oral naming tasks. Subcortical stimulation by using the same current threshold was applied during tumor resection, in a back and forth fashion, and the same tests. RESULTS Cortical sites essential for oral naming were found in 87.5% of patients, those for the first acquired language in 1 to 4 sites, those for the other languages in 1 to 3 sites. Sites for each language were distinct and separate. Number and location of sites were not predictable, being randomly and widely distributed in the cortex around or less frequently over the tumor area. Subcortical stimulations found tracts for the first acquired language in 4 patients, and for the other languages in 3 patients. Three of these patients decreased their fluency immediately after surgery, affecting the first acquired language, which fully recovered in two patients and partially in one. The procedure was agile and well tolerated by the patients. CONCLUSION These findings show that multiple cortical and subcortical language mapping during awake craniotomy for tumor removal is a feasible procedure. They support the concept that intraoperative mapping should be performed for all the languages the patient is fluent for to preserve functional integrity.