Clinical Utility of Preoperative Bilingual Language fMRI Mapping in Patients with Brain Tumors

Abstract

BACKGROUND AND PURPOSE Previous literature has demonstrated disparity in the postoperative recovery of first and second language function of bilingual neurosurgical patients. However, it is unclear to whether preoperative brain mapping of both languages is needed. In this study, we aimed to evaluate the clinical utility of language task functional MRI (fMRI) implemented in both languages in bilingual patients. METHODS We retrospectively examined fMRI data of 13 bilingual brain tumor patients (age: 23 to 59 years) who performed antonym generation task‐based fMRIs in English and non‐English language. The usefulness of bilingual language mapping was evaluated using a structured survey administered to 5 neurosurgeons. Additionally, quantitative comparison between the brain activation maps of both languages was performed. RESULTS Survey responses revealed differences in raters’ surgical approach, including asleep versus awake surgery and extent of resection, after viewing the language fMRI maps. Additional non‐English fMRI led to changes in surgical decision‐making and bettered localization of language areas. Quantitative analysis revealed an increase in laterality index (LI) in non‐English fMRI compared to English fMRI. The Dice coefficient demonstrated fair overlap (.458 ± .160) between the activation maps. CONCLUSION Bilingual fMRI mapping of bilingual patients allows to better appreciate functionally active language areas that may be neglected in single language mapping. Utility of bilingual mapping was supported by changes in both surgical approach and LI measurements, suggesting its benefit on preoperative language mapping.

Organizing Variables Affecting fMRI Estimates of Language Dominance in Patients with Brain Tumors

“…The volume of language activation in the left-dominant hemisphere in L1 was the same in those patients as in the monolingual controls [14]. Moreover, a study [92] involving bilingual patients with brain tumors found that fMRI language mapping performed in both languages provided a superior appreciation of the language network than mapping in only one language (i.e., more language-related regions were identified). This finding has been confirmed by a recent systematic review of studies with patients (including individuals with brain tumors) who underwent neurosurgical language mapping (pre-operative fMRI, Wada, and/or electrical stimulation mapping) [93].…”

Standardization of presurgical language fMRI in Greek population: Mapping of six critical regions

“…To the best of our knowledge, this is the first study to standardize a protocol for language mapping in Greek, while at the same time, this protocol is able to reliably activate a language system wider than the Wernicke–Lichtheim–Geschwind model. Apart from the Greek native speakers, this may prove important for Greek bilingual speakers in other countries undertaking neurosurgery, as many studies suggest that language areas near tumors activate more reliably in the native language when compared to the later acquired languages (Kuper et al., 2021 ; Leung et al., 2020 ; Protopapas et al., 2016 ).…”

Functional MRI study of language organization in left-handed and right-handed trilingual subjects

“…Lastly, our study consisted of healthy volunteers only. Studies have shown that language laterality values can differ across languages in patients suffering from epilepsy or tumors 4,7 . Furthermore, L1 was found on cortical mapping to present more positive language sites than L2 and L3 in patient with high proficiency in foreign languages 13,25,26 .…”

“…At least more than half the world's population is bilingual 3 . Extensive research has been conducted on language organization in bilingual [4][5][6][7][8][9][10][11] and multilingual populations [12][13][14][15][16] . Several factors have been identified as playing a role in the organization of language in multilingual subjects.…”