How Tumor Invasion Size and Location Affects Language Function Decline in Presurgical fMRI Mapping

Oghabian M A, Sedighi N, Izanlou M, Safavian N, Kalantar-Hormozi H, Sepahdoost M, Ghodsi SM and Haghshenas SH

Published on: 2022-12-09


In patients with brain tumors close to eloquent area, the dislocation of language activation areas is anticipated to be observed, both to healthy ipsilateral regions and/or to contralateral homologous areas, also known as neuroplasticity. It is hypothesized that a functional and structural pattern is altered primarily based on the type, size, and location of the tumor and its degenerated area. In this research, we investigated the effect of tumor size and location using BOLD fMRI study on patients with brain masses close to the main language network areas. In our study, patients with brain tumors who had no speech problems were divided into three groups; with no disruptive involvement (non-invasion group), with a moderate effect (partial- invasion group), and those having severe eloquent cortex involvement (severe-invasion group). First, the destructive effect of tumor invasion on functional language integrity was investigated using differences between the activation pattern of the non-invasive group compared to the partial-invasion and severe-invasion groups. In the second step, we designed the study to investigate the brain's plasticity in the case of the observed destructive lingual network by relatively slow-growing glial tumors in Broca’s area. We examined both the severe-invasion and partial-invasion groups compared with the non- invasive group. Consequently, we found no significant change in the language functional activity in the cases where the tumors were outside the main language area (ie Broca). However, the destructive effect was observed in partial-invasion and severe-invasion groups, although the main language functions were reserved in both cases due to reorganization and plasticity mechanism. It was shown that as the tumor invasion increases, the brain starts to regenerate in alternative associated primary areas of the language network, then its activity moves to the secondary areas, initially to the ipsilesional and in the more severe stage, to the contralesional hemisphere.