208 Multivariate Mapping of Low-Resilient Neurocognitive Systems Within and Around Low-Grade Gliomas

INTRODUCTION: The brain exhibits a remarkable capacity for functional compensation in response to neurological damage. This propensity is particularly exemplified by diffuse low-grade gliomas (DLGGs). However, plasticity is not boundless, and surgical resections directed at structures with limited neuroplasticity may lead to incapacitating impairments. Yet, maximizing DLGG resections offers oncological benefits, especially when the resection extends beyond the tumor margins (i.e., supra-tumor or supratotal resection). METHODS: We leveraged a cohort of 400 DLGG patients who underwent surgery with awake mapping. Patients benefited from a neuropsychological assessment (18 subtasks) before and 3 months post-surgery. We applied topography and disconnection-focused multivariate lesion-symptom mapping (LSM) using support vector regressions. RESULTS: The observed changes in performance were of a limited magnitude, suggesting an overall recovery. LSM analyses revealed that a lack of recovery in picture naming was linked to damage in the left inferior temporal gyrus and inferior longitudinal fasciculus. For semantic fluency abilities, an association was established with damage to the left precuneus. For phonologic fluency abilities, the left dorso-medial frontal cortex and the frontal-aslant tract were implicated. Spatial exploration difficulties were associated with injury to the right dorsomedial prefrontal cortex. An analysis of the contribution of intrinsic features of surgical resections to performance suggested that the more extensive supra-tumoral resections in areas such as the left uncinate fasciculus, hippocampus and para-hippocampus, or the right frontal-mesial areas, the less pronounced the recovery was in naming, episodic memory, and visuospatial exploration, respectively. CONCLUSIONS: These results shed new light on both low-resilient neural systems and the prediction of cognitive recovery following glioma surgery. Furthermore, they indicate that supratotal resections were only occasionally less well-tolerated from a cognitive viewpoint.