Awake surgery with cognitive monitoring has increasingly been implemented to preserve brain networks and functionality. More recently, not only surgery in the left but also in the right hemisphere, i.c., the parietal lobe, was associated with potential risk for deficits in cognitive functions, such as cognitive flexibility. In this explorative pilot study, we compare cognitive performance more than three months after surgery with baseline measurements and explore the association between cognitive decline and subcortical tracts that may have been severed during surgery in the right hemisphere. Twenty-two patients who underwent surgery for a right parietal low-grade glioma were assessed pre- and postoperatively using the Trail Making Test and the Stroop task to administer set-shifting abilities and inhibition. Volume measurements and lesion–symptom mapping analyses were performed on postoperative MRI scans. Careful interpretation of the results shows a change in TMT performance and not on the Stroop Task when the lateral part of the arcuate fasciculus is damaged, indicating that disconnection of the lateral part of the dorsal stream might be correlated specifically with impaired set-shifting and not with inhibition. More importantly, this study underlines the need for international concertation to allow larger studies to increase power and perform more detailed analyses.

BACKGROUND AND OBJECTIVES: This retrospective cohort study reviewed the feasibility and applicability of awake surgery for glioma in patients with clinically relevant preoperative language deficits, specifically focusing on intraoperative language monitoring and its impact on postoperative language outcomes. METHODS: Group and individual analyses were conducted to compare preoperative and postoperative language deficits. In addition, an overview of intraoperative tests was provided, and an evaluation of the monitoring process was performed. RESULTS: In 100% of patients with significant (z score ≤ −1 SD) preoperative language deficits (N = 48), language tasks could be performed during awake surgery. In 90% of these cases, functional boundaries for language function were found during surgery. CONCLUSION: This study confirms the feasibility and applicability of monitoring language functions during awake brain surgery when preoperative language deficits are present. Both low-grade and high-grade glioma patients show an overall stable performance on a language comprehension test and an improved performance on a language production test 3 to 6 months after surgery and, therefore, seemed to benefit from cognitive monitoring.

Purpose: Impairments in executive functioning (EF) and inhibitory control (IC) negatively affect patients’ health-related quality of life. We introduced an intraoperative Stroop task (iST) as means of monitoring IC. This study summarizes lessons learned over the past decade since implementation of iST. We focus on its feasibility, potential in preserving EF and anatomical correlates of intraoperative errors. Methods: We retrospectively examined 119 treatment-naïve WHO grade II-IV glioma patients, undergoing awake surgery and perioperative neuropsychological testing between 2010–2020. We compared clinical characteristics between iST and non-iST patients. We examined EF including IC at both group and individual level. Patients underwent magnetic resonance scanning according to clinical routine, from which preoperative glioma location and iST error type maps were constructed. Results: The iST appeared feasible where it was planned to be performed in a broad glioma population (118/119; 99%) with minimal impact on patient and surgical procedure burden. Stimulation elicited inhibition errors ( n = 64; 54%) and excessive slowing ( n = 71, 60%) on the iST. IC and EF were preserved similarly across subgroups. Individual performances declined (< -1.5SD) more frequently in patients with high-grade than low-grade gliomas at 3–6 months post-surgery. Gliomas in the left frontal lobe were associated with increased odds of slowing and inhibition errors, contrary to right frontal and parietal lobe involvement. Five patients (4%) developed new postoperative EF or IC impairments, despite iST monitoring. Conclusion: Our findings indicate that iST is a feasible tool for intraoperative monitoring of IC in glioma patients, imposing minimal additional burden on both patient and surgical procedure preserving EF and IC among iST patient subgroups. The iST can elicit errors in various brain regions, with a predilection for the left frontal lobe. The overall low incidence of cognitive decline leading to cognitive impairments supports the efficacy of iST in preserving EF and specifically IC during awake surgery.