Asman, Priscella

OBJECTIVE Protocols for intraoperative mapping during awake craniotomy vary widely. The aim of this study was to evaluate how the number and type of intraoperative neuropsychological paradigms administered via NeuroMapper, a tablet-based platform, during awake glioma surgery affect positive mapping rates, return to work (RTW), and oncological outcomes. Factors associated with the operative duration and early postoperative neurological deficits were of additional interest. METHODS This single-center retrospective study included patients with diffuse low- and high-grade gliomas who underwent awake craniotomy with NeuroMapper-guided mapping between 2018 and 2024. Primary outcomes were RTW, progression-free survival (PFS), and overall survival (OS); operative duration and early postoperative deficits were secondary outcomes. Covariate balancing propensity score (CBPS) analysis was used to address confounding by tumor grade, with all postweighting standardized mean differences < 0.10. A weighted logistic regression model assessed RTW, and CBPS-weighted Cox models assessed PFS and OS. Linear regression was used to analyze intraoperative variables, operative duration, and early postoperative deficits. RESULTS Of 189 patients included in the analysis, 65 had LGG (median age 39 years) and 124 had HGG (median age 56 years). Mapping complexity varied, with 1–6 tasks used (median 4). Weighted multivariate logistic regression analysis identified the following independent predictors of RTW: preoperative Karnofsky Performance Status score ≥ 80 (OR 1.37, p = 0.039), absence of recurrent disease (OR 0.30, p < 0.001), use of 5–6 paradigms (OR 1.54, p = 0.047), positive mapping (OR 2.41, p = 0.017), and subtotal resection (OR 4.43, p = 0.002). Intraoperative seizure, early postoperative deficit, and the resection technique were not significant. IDH mutation status was associated with improved PFS (HR 0.15, p < 0.001), while subtotal resection was associated with worsened PFS (HR 3.00, p < 0.001). Positive mapping was associated with better OS (HR 0.57, p = 0.04). The operative duration was unaffected by mapping variables but was longer in patients with obesity (β = 0.28, p = 0.038). CONCLUSIONS Positive NeuroMapper-guided mapping of more diverse linguistic functions was associated with RTW and longer OS. Additionally, mapping complexity did not prolong surgery times, supporting potential standardization.

Abstract INTRODUCTION Preserving language during tumor resection is critical but challenged by the time-intensive, complex nature of direct electrical stimulation (DES). High-gamma electrocorticography (ECoG) captures real-time, task-induced cortical responses, yet its spatiotemporal concordance with DES across language tasks remains underexplored. OBJECTIVE To evaluate how early and late high-gamma ECoG responses align with DES across auditory, object, action, and descriptive naming tasks. METHODS Seventeen patients (14 gliomas, 3 metastases) underwent awake craniotomy. ECoG was recorded, and bipolar DES was applied on the same subdural grid across the four tasks using adjacent contacts. Early (100–200 ms) and late (&gt;200 ms) high-gamma activity (30–150 Hz) and DES-positive sites were co-registered with a standard MNI-152 brain. The spatial overlap was quantified using Dice-Sørensen (D-S) coefficients with accuracy assessed by ECoG–DES contact proximity (exact/adjacent, &lt;1 cm) across tumor, peritumoral (&lt;2 cm), and whole-grid ROIs. Patient language outcomes were determined from longitudinal neurologic exams. RESULTS DES-positive sites were identified in 15/17 (88%) patients, primarily during auditory and action naming. Auditory naming elicited gamma activity in all patients, with early and late responses, reflecting sensory and extended semantic processes, observed in 10/17(59%) cases, showing strong concordance with DES (early: D-S= 0.63, 95% CI: 0.51–0.74; early + late: D-S = 0.66, 95% CI: 0.54–0.77). Non-auditory tasks showed predominantly late gamma responses, with modest DES overlap (object: D-S= 0.34; action: D-S= 0.42; descriptive: D-S= 0.37) suggesting border distributed cortical networks. Accuracy in all tasks ranged from 76–95% within the whole grid; auditory naming achieved 83% sensitivity and 82% specificity in peritumoral ROI. At 6 months, 14/17 (82%) patients had no speech deficits; 8/9 with preoperative deficits improved while 2 had a new deficit. CONCLUSION Gamma activity during auditory naming reliably predicts DES-defined language eloquence for safe maximal resection of brain tumors.

Abstract BACKGROUND Intraoperative electrocorticography (ECoG) may aid localization of language function and help guide eloquent brain tumor resection. However, relevance of ECoG findings to language outcomes remains unclear. METHODS Fifteen patients with brain tumors (Mdn age=60; 67% high-grade glioma) underwent awake craniotomy and intraoperative language mapping. Time-frequency ECoG gamma activity was visualized in real-time followed by direct electrical stimulation (DES) across 3 paradigms (NeuroMapper Tasks: Object, Action, Auditory). Early and late ECoG gamma modulations and positive DES sites were co-registered with postoperative MRI. A subset (N=11) completed expressive language testing (Phonemic and Semantic Fluency, Confrontation Naming) prior to and &lt;2 months following surgery. Correlational analyses and Mann-Whitney U tests examined relationships between test results and surgical impact upon expressive task-elicited gamma activity (Object and Action Naming). RESULTS Across tasks, positive DES sites were identified in 93% of cases (Auditory, 73%; Action, 71%, Object, 57%). No positive DES sites were resected. Early and/or late gamma activations were elicited in all patients, resected in 40%, and within 1 cm of surgical impact in 90%. Four patients (36%) showed reliable decline on at least 1 outcome, which was associated with Action Naming activity &lt;1 cm of surgical impact (phi=.67, p=.035). On individual tests, Confrontation Naming and Phonemic Fluency decline were rare (9% and 18%), though Semantic Fluency declined in 36% of patients. Change in Semantic Fluency was associated with resection of Object Naming gamma sites (Z=-1.83, p=.044) and presence of Action Naming gamma features near surgical impact (Z=-2.25, p=.014). CONCLUSIONS Despite preservation DES sites and sparing of basic confrontation naming ability, verbal fluency declined in a substantial group of patients. Decline was associated with gamma features resected or near surgical impact. While preliminary, findings suggest task-based ECoG can augment DES in informing risk of surgically-acquired language decline.

Abstract BACKGROUND As an adjunct to direct electrical stimulation (DES), intraoperative electrocorticography (ECoG) can aid detection of language-eloquent cortex. However, it is unclear how surgical impact upon mapping findings relates to cognitive-linguistic outcomes. METHODS Ten patients underwent awake craniotomy for tumor resection with ECoG and DES language mapping. Mapping utilized iPad stimulus presentation coupled to an electrode array capable of both recording ECoG activity and delivering DES. Time-frequency gamma band activations were visualized (Early, Long, Late, Double Peak) for 3 naming paradigms (Object, Action, Auditory). DES was also conducted for each task. Mapping results were overlayed on postoperative MRI to examine proximity to parenchymal trauma (cavity, sulcal displacement). Patients completed cognitive-linguistic testing [WAB-R (N=3) or Neuropsychological Assessment (N=7)] prior to surgery and &lt;2 months postoperatively. Patients with persisting aphasia at 6-month follow-up were also identified. RESULTS Postoperative language decline was found in 50% of patients, with 30% showing worsening (&gt;1SD) in Naming and Phonemic Fluency, and 60% in Semantic Fluency. Surgery impacted ECoG features in 60% of patients and DES arrest sites in 30%. A trend was observed where Early and Late Object naming ECoG features were associated with Semantic Fluency decline [rpb(5)=-.69, p=.067]. Arrest during Auditory naming DES &lt;1 cm of surgical effect was associated with decline in Abstraction [rpb(5)=-.83, p=.042; FET, p=.029] and Semantic Fluency [rpb(5)=-.87, p=.012; FET, p=.024]. Excluding the 3 transsulcal surgeries, arrest during Auditory naming DES &lt;1 cm of resection was associated with general language decline [FET, p=.047]. All 3 patients with persisting aphasia had Auditory naming arrest &lt;1 cm of resection and 2/3 patients had Object naming ECoG features resected. CONCLUSIONS While preliminary, results suggest that surgical proximity to ECoG and DES mapping results may inform risk of surgically-acquired cognitive-linguistic decline. Findings support the potential of multimethod-multitask intraoperative language mapping.

Abstract BACKGROUND Few studies have examined concordance between intraoperative electrocorticography (ECoG) and direct electrical stimulation (DES) language mapping, especially across varied naming tasks. METHODS Twelve patients (Mdn age=59; 75% HGG) underwent awake craniotomy with ECoG and DES language mapping. Mapping utilized iPad stimulus presentation coupled to a 4x8 electrode array for both ECoG and DES. Time-frequency ECoG gamma band activity (Early and Late) was visualized for 3 naming paradigms (Object, Action, Auditory). Bipolar DES was also conducted for each task at each electrode pair. ECoG activations and DES hits were overlayed on preoperative MRI. DES hits represented ground truth for eloquence. ECoG accuracy was examined for each task with 3 different criteria: exact (identical electrodes for ECoG activation and DES hits), adjacent (ECoG &lt;1cm of DES hits), and adjacent within a predefined peritumoral region of interest (&lt;2 cm from boundaries). RESULTS 32 DES hits (40% Auditory, 32% Action, 28% Obj) were observed across patients. Exact ECoG-DES accuracy ranged from 78%-90% [Object: Sens=11%, Spec=91%, PPV=6%, NPV=95%; Action: Sens=40%, Spec=93%, PPV=24%, NPV=97%; Auditory: Sens=69%, Spec=78%, PPV=19%, NPV=78%]. Adjacent ECoG-DES accuracy ranged from 82%-91% [Object: Sens=33%, Spec=92%, PPV=18%, NPV=97%; Action: Sens=44%, Spec=93%, PPV=25%, NPV=97%; Auditory: Sens=91%, Spec=81%, PPV=37%, NPV=99%]. When restricted to the peritumoral region, adjacent ECoG-DES accuracy ranged from 94%-97% [Object: Sens=14%, Spec=99%, PPV=25%, NPV=97%; Action: Sens=25%, Spec=99%, PPV=25%, NPV=99%; Auditory: Sens=100%, Spec=94%, PPV=54%, NPV=100%]. For patients with DES hits (N=10), all had at least 1 task activation &lt;1 cm of DES hits, with 7/10 having convergence of activations across at least 2 tasks. CONCLUSIONS Negative ECoG mapping is strongly predictive of non-eloquence confirmed by DES for all naming tasks. Additionally, gamma band activation elicited by auditory naming within the peritumoral region is strongly predictive of eloquence. Findings support task-based ECoG language mapping for prediction of eloquence and identification of targets for DES confirmation.

Abstract INTRODUCTION Accurately mapping sensorimotor regions is crucial for preserving motor and sensory functions in the treatment of gliomas located in the peri-Rolandic areas of the brain. OBJECTIVE We examined the use of high-density electrocorticography (ECoG) for passive mapping of sensorimotor regions in treating peri-Rolandic gliomas by analyzing the spatial-temporal and spectral features of real-time somatosensory evoked potentials (SSEPs), and their spectral patterns in differentiating states of consciousness. METHODS During surgery, SSEPs were recorded using high-density ECoG on fourteen patients (n=14), both in anesthetized and awake states. Neural data from 0.6Hz median nerve stimulation were captured at 2.4kHz and processed in real-time using MATLAB Simulink. The system displayed SSEPs’ peak activations as a 2D heat map on a screen, particularly around the 20ms time point (N20), and generated the spectral power in the gamma range using the Stockwell transform. Accuracy in delineating the central sulcus (CS) was assessed using the ROC curve, and paired t-tests compared gamma oscillations between states of consciousness. RESULTS Patients consistently showed clear discrimination between anterior and posterior channels at the 20ms time point, with 93.6±14.9% accuracy. Color contrast delineated the CS, correlating with the sulcus in the 3D reconstructed magnetic resonance imaging of each patient. Late gamma (60–250 Hz) modulation occurred 50 ms after stimulation onset, extending up to 250 ms in the primary somatosensory area. It was suppressed in the anesthetized state and significantly increased in the awake state (delineation accuracy: 81±10.3% and 91±13.4%, respectively). CONCLUSIONS These results demonstrate that SSEPs and gamma modulations can delineate sensorimotor areas and assess consciousness, significantly impacting neurosurgical planning.