Intraoperative Language mapping in a Japanese-English-French trilingual patient with a left Temporal lobe glioma: a case report.

Event Abstract Back to Event Is awake brain surgery in high-grade glioma patients and a severe aphasia feasible? A case study. Djaina Satoer1*, Joost Schouten1, Ismail Eralp2, Arnaud Vincent1 and Evy Visch-brink1 1 Department of Neurosurgery, Erasmus Medical Center, Erasmus University Rotterdam, Netherlands 2 Department of Anesthesiology, Erasmus Medical Center, Erasmus University Rotterdam, Netherlands Introduction. Awake brain surgery with intraoperative direct electrical stimulation (DES) is the gold standard treatment for low-grade gliomas (LGG) in eloquent areas aiming at maximal tumor resection with language preservation (De Witt Hamer, Robles, Zwinderman, Duffau, & Berger, 2012; Duffau, 2018). High-grade gliomas (HGG, WHO grade III, IV) are typically treated with classical surgery (non-awake). A recent meta-analysis revealed that awake surgery in HGG enhanced better surgical outcomes (e.g. overall survival, gross total resection) (Gerritsen, Arends, Klimek, Dirven, & Vincent, 2019). However, as language deficits in HGG are generally more severe than in LGG (Noll, Sullaway, Ziu, Weinberg, & Wefel, 2015), DES becomes a challenge: the distinction between pre-existent aphasia and DES induced paraphasias is less clear. Preoperative severe aphasia is even a contraindication for awake brain surgery (Dziedzic & Bernstein, 2014). Aim. To demonstrate neurolinguistic procedure in awake surgery in a HGG patient with severe aphasia. Methods. We present “G2” (right-handed male, 70 years old) with a large (50 x 41 mm) glioblastoma multiforme (GBM, WHO grade IV) in the left temporal lobe (Wernicke’s area), elected for awake surgery. Extensive neurolinguistic examination was performed pre- and 3 months postoperatively. Results. Preoperatively, G2 presented with an aphasia with Wernicke characteristics (TT score 5.5/36) with impairments in object naming, repetition and the auditory input route. Errors in speech production except reading aloud consisted of phonological paraphasias, neologisms, stereotypes and perseverations. Semantic judgment (odd-picture/word-out), reading aloud (words, short sentences) and sentence completion with one word (DuLIP, De Witte et al., 2015) were intact. Intraoperatively, test-instructions and stimuli were visually presented on a tablet. Correct items from object naming (DuLIP) were selected for DES: no reproducible language errors (1 semantic paraphasia, 1 neologism) were elicited with repeated DES, indicating the absence of critical cortical language areas. During resection, semantics, reading aloud and sentence completion remained stable. Tumor resection was discontinued when new neologisms and perseverations occurred during object naming (subcortical level). Extent of resection: gross total. Postoperatively (3 months), G2 remained stable in semantic tasks, improved in object naming and the Token Test and deteriorated in repetition (due to the defective auditory input route; for test scores, see Table 1). Discussion. For the first time we demonstrated that awake surgery with DES was possible in a patient with severe aphasia. Extensive preoperative neurolinguistic investigation of different input and output routes (auditory, visual) is necessary to make adequate selection of language tests/items. By doing so, the linguist can focus on the intact linguistic modality/level which facilitates reliable interpretation of further language deterioration (nature and severity of paraphasias) during surgery. We made use of the intact visual input route to present test instructions and to monitor language during awake brain surgery. Findings in this case suggest that awake surgery in GBM is safe and feasible. High expertise of a multidisciplinary awake team is mandatory, including a specialized clinical linguist. A case-series will follow and a RCT is currently ongoing to assess the added value of awake surgery in GBM (SAFE Trial NL7589). Figure 1 References De Witt Hamer, P. C., Robles, S. G., Zwinderman, A. H., Duffau, H., & Berger, M. S. (2012). Impact of intraoperative stimulation brain mapping on glioma surgery outcome: a meta-analysis. J Clin Oncol, 30(20), 2559-2565. doi:10.1200/jco.2011.38.4818 De Witte, E., Satoer, D., Robert, E., Colle, H., Verheyen, S., Visch-Brink, E., & Marien, P. (2015). The Dutch Linguistic Intraoperative Protocol: a valid linguistic approach to awake brain surgery. Brain Lang, 140, 35-48. Duffau, H. (2018). Is non-awake surgery for supratentorial adult low-grade glioma treatment still feasible? Neurosurg Rev, 41(1), 133-139. doi:10.1007/s10143-017-0918-9 Dziedzic, T., & Bernstein, M. (2014). Awake craniotomy for brain tumor: indications, technique and benefits. Expert Rev Neurother, 14(12), 1405-1415. Gerritsen, J. K. W., Arends, L., Klimek, M., Dirven, C. M. F., & Vincent, A. J. E. (2019). Impact of intraoperative stimulation mapping on high-grade glioma surgery outcome: a meta-analysis. Acta Neurochir (Wien), 161(1), 99-107. Keywords: awake brain surgery, Language mapping, Severe aphasia, glioblastoma multiform (GBM), case study Conference: Academy of Aphasia 57th Annual Meeting, Macau, Macao, SAR China, 27 Oct - 29 Oct, 2019. Presentation Type: Poster presentation Topic: Not eligible for student award Citation: Satoer D, Schouten J, Eralp I, Vincent A and Visch-brink E (2019). Is awake brain surgery in high-grade glioma patients and a severe aphasia feasible? A case study.. Front. Hum. Neurosci. Conference Abstract: Academy of Aphasia 57th Annual Meeting. doi: 10.3389/conf.fnhum.2019.01.00046 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 05 May 2019; Published Online: 09 Oct 2019. * Correspondence: Dr. Djaina Satoer, Department of Neurosurgery, Erasmus Medical Center, Erasmus University Rotterdam, Rotterdam, Netherlands, d.satoer@erasmusmc.nl Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Djaina Satoer Joost Schouten Ismail Eralp Arnaud Vincent Evy Visch-brink Google Djaina Satoer Joost Schouten Ismail Eralp Arnaud Vincent Evy Visch-brink Google Scholar Djaina Satoer Joost Schouten Ismail Eralp Arnaud Vincent Evy Visch-brink PubMed Djaina Satoer Joost Schouten Ismail Eralp Arnaud Vincent Evy Visch-brink Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Intraoperative language mapping in awake surgery is typically conducted by asking the patient to produce automatic speech and to name objects. These tasks might not map language with sufficient accuracy, as some linguistic processes can only be triggered by tasks that use verbs and sentences. Verb and sentence processing tasks are currently used during surgery, albeit sparsely. Medline, PubMed, and Web of Science records were searched to retrieve studies focused on language mapping with verbs/sentences in awake surgery. We review the tasks reported in the published literature, spell out the language processes assessed by each task, list the cortical and subcortical regions whose stimulation inhibited language processing, and consider the types of errors elicited by stimulation in each region. We argue that using verb tasks allows a more thorough evaluation of language functions. We also argue that verb tasks are preferable to object naming tasks in the case of frontal lesions, as lesion and neuroimaging data demonstrate that these regions play a critical role in verb and sentence processing. We discuss the clinical value of these tasks and the current limitations of the procedure, and provide some guidelines for their development. Future research should aim toward a differentiated approach to language mapping - one that includes the administration of standardized and customizable tests and the use of longitudinal neurocognitive follow-up studies. Further work will allow researchers and clinicians to understand brain and language correlates and to improve the current surgical practice.

Intraoperative functional language mapping is vital to minimize the risks associated with surgical removal of the seizure onset zone in selected patients with epilepsy. In children, this method has been reported extraoperatively by the placement of invasive electrodes to map the language area and monitor epileptic activity. It is difficult from a technical standpoint to perform an awake craniotomy and language mapping in young children under 10years of age. Here we report a 9-year-old boy suffering from drug-resistant non-lesional epilepsy who underwent extraoperative and intraoperative electrical stimulation with successful identification of Broca's language area. Electrocorticography (ECOG) was applied intraoperatively in a continuous manner utilizing grid electrodes before the skin opening. We found that the use of visual digital video games facilitated extraoperative and intraoperative cortical mapping. Cortical language inhibition by electrical stimulation was elicited at an amplitude of 7mA (100μs single-phase duration and 50Hz pulse width). Resection of the seizure onset zone was completed safely. The post-resection ECOG revealed the disappearance of epileptogenic electrographic discharges at the seizure onset contacts and at other involved contacts in the epileptogenic zone. After surgery, the child recovered well with no language deficits and remained seizure-free. The child remembered only the video game test that was performed intraoperatively. This report highlights safety strategies for awake language mapping in pediatrics and the importance of the perioperative use of a visual digital video game and continuous ECOG, in addition to the use of targeted language cortex stimulation to facilitate faster and safer intraoperative language mapping under awake conditions in this age group.

Predictors of Patient Inability to Cooperate during Intraoperative Language Mapping

A computerized platform has been developed to enhance behavioral testing during intraoperative language mapping in awake craniotomy procedures. The system is uniquely compatible with the environmental demands of both the operating room and preoperative functional MRI (fMRI), thus providing standardized testing toward improving spatial agreement between the 2 brain mapping techniques. Details of the platform architecture, its advantages over traditional testing methods, and its use for language mapping are described. Four illustrative cases demonstrate the efficacy of using the testing platform to administer sophisticated language paradigms, and the spatial agreement between intraoperative mapping and preoperative fMRI results. The testing platform substantially improved the ability of the surgeon to detect and characterize language deficits. Use of a written word generation task to assess language production helped confirm areas of speech apraxia and speech arrest that were inadequately characterized or missed with the use of traditional paradigms, respectively. Preoperative fMRI of the analogous writing task was also assistive, displaying excellent spatial agreement with intraoperative mapping in all 4 cases. Sole use of traditional testing paradigms can be limiting during awake craniotomy procedures. Comprehensive assessment of language function will require additional use of more sophisticated and ecologically valid testing paradigms. The platform presented here provides a means to do so.

Intraoperative language mapping is standard for resection of gliomas involving language pathways, because it enables a maximal safe tumor removal. Intraoperative language mapping is a demanding procedure requiring a good level of patient collaboration, a complex peri-operative organization, and may cause patient fatigue. The selection of patients to submit to such a procedure is critical. The efficacy of intraoperative mapping is widely recognized for Low Grade Gliomas, the use for surgical removal of high grade gliomas (HGGs) is still under debate. We evaluated the efficacy of the use of intraoperative language mapping for resection of HGGs involving language pathways, to identify for which subtype of patients is highly recommended, and for which can be optional. 2 groups were included. In the first group (126 patients) removal was performed asleep, with the aid of neurophysiological monitoring. In the second group (157 patients) resection was performed awake with the aid of cortical and subcortical language mapping and neurophysiological monitoring. Patients and tumor characteristics (location, radiological appearance on conventional MR, pattern of tract dislocation/infiltration in DTI FT images) were considered. Results were evaluated as immediate/permanent deficits (by neuropsychological evaluation) and extent of resection (on volumetric gadolinium enhanced T1 weighted MR images). In the first group, 65 tumors were frontal, 61 temporal. 108 were involving the cortex, 18 were deep seated. DTI depicted the Tract located at the tumor periphery in 111 patients, inside the tumor in the remaining. 32 patients had pre-operative mild or moderate language deficits. Resection was continued till microscopically normal parenchyma was encountered. Total resection was achieved in 97.6% of cases. In 35 (27.8%) of patients, immediate post-operative deficits were observed, which remained as permanent in 16 patients. 87.5% of patients with pre-operative language deficits recovered in the post operative period. Patients who developed permanent deficits were those with deep seated tumors. In the second group of tumors, 72 were frontal, and 85 temporal, 112 superficial, 45 were not reaching the cortex. DTI depicted the tract located in the tumor periphery in 128 patients, inside the tumor in the remaining. 25 patients had pre operative mild language deficits. Resection was continued till functional boundaries were reached. Immediate post operative language deficits were shown in 41 (26.1%) patients, with complete recovery within a month in all patients. Total resection was reached in 96.1% of cases. Removal of language pathways tumors does not strictly requires the use of subcortical language mapping when the tumor reach the surface. Resection of deep seated tumors or of tumors with infiltrated tracts (as depicted by DTI) requires the use of subcortical mapping to achieve a safe tumor removal.

The goal of this study was to evaluate the feasibility, benefit, and safety of awake brain surgery (ABS) and intraoperative language mapping in children and adolescents with structural epilepsies. Whereas ABS is an established method to monitor language function in adults intraoperatively, reports of ABS in children are scarce. A retrospective chart review of pediatric patients ≤ 18 years of age who underwent ABS and cortical language mapping for supratentorial tumors and nontumoral epileptogenic lesions between 2008 and 2019 was conducted. The authors evaluated the global intellectual and specific language performance by using detailed neuropsychological testing, the patient's intraoperative compliance, results of intraoperative language mapping assisted by electrocorticography (ECoG), and postsurgical language development and seizure outcomes. Descriptive statistics were used for this study, with a statistical significance of p < 0.05. Eleven children (7 boys) with a median age of 13 years (range 10-18 years) underwent ABS for a lesion in close vicinity to cortical language areas as defined by structural and functional MRI (left hemisphere in 9 children, right hemisphere in 2). Patients were neurologically intact but experiencing seizures; these were refractory to therapy in 9 patients. Compliance during the awake phase was high in 10 patients and low in 1 patient. Cortical mapping identified eloquent language areas in 6/10 (60%) patients and was concordant in 3/8 (37.5%), discordant in 3/8 (37.5%), and unclear in 2/8 (25%) patients compared to preoperative functional MRI. Stimulation-induced seizures occurred in 2 patients and could be interrupted easily. ECoG revealed that afterdischarge potentials (ADP) were involved in 5/9 (56%) patients with speech disturbances during stimulation. None of these patients harbored postoperative language dysfunction. Gross-total resection was achieved in 10/11 (91%) patients, and all were seizure free after a median follow-up of 4.3 years. Neuropsychological testing using the Wechsler Intelligence Scale for Children and the verbal learning and memory test showed an overall nonsignificant trend toward an immediate postoperative deterioration followed by an improvement to above preoperative levels after 1 year. ABS is a valuable technique in selected pediatric patients with lesions in language areas. An interdisciplinary approach, careful patient selection, extensive preoperative training of patients, and interpretation of intraoperative ADP are pivotal to a successful surgery.

ABSTRACTPurposeThe purpose of this overview is to compare Direct Electrical Stimulation (DES) and Electrocorticography (ECoG) techniques, assessing their respective strengths, limitations, and roles in ensuring successful language mapping during awake brain surgeries.MethodThis overview aims to compare two techniques used in intraoperative language mapping during awake brain surgery: Direct Electrical Stimulation (DES) and Electrocorticography (ECoG). By summarizing recent advances in both methods, we highlight their respective mechanisms, applications, and roles in improving surgical outcomes. DES is widely considered the gold standard for cortical brain mapping and is applicable in both awake and anesthetized surgeries for treating epilepsy and brain tumors. In contrast, ECoG involves monitoring the brain's electrical activity with or without direct stimulation, as it provides valuable insight into high gamma activity (70–150 Hz), which is strongly associated with speech production.FindingECoG offers a high‐resolution approach to language mapping by detecting high‐gamma activity, reducing the risk of intraoperative seizures, and serving as a complementary or alternative tool to DES in specific clinical scenarios. While DES continues to be the most reliable technique for identifying functional brain areas, it does carry a higher risk of inducing seizures. Furthermore, recent advancements in ECoG‐based speech decoding and brain–computer interfaces (BCIs) underscore the growing potential of ECoG in restoring communication in patients with severe language impairments, extending its applications beyond surgical mapping.ConclusionIn conclusion, while DES remains the gold standard for intraoperative language mapping, ECoG is emerging as a promising complementary or alternative technique in some clinical cases. This overview highlights the evolving role of ECoG, particularly in the context of speech decoding and BCIs, offering new possibilities for improving surgical outcomes and postoperative quality of life in patients.

The present study sought to test the hypothesis that the production of speech and the comprehension of speech in the left temporal lobe can be anatomically disassociated. Moreover, it is aimed to show that the standard intraoperative object naming task is not sufficient to test all the functionally essential areas in the left temporal lobe. In the introductory part of the article we described the existing information about the left temporal lobe and the awake surgery procedure. In the course of the study, we collected and analyzed the data from intraoperative brain mapping of 25 patients with brain lesions – gliomas or pharmacoresistant epilepsy, who underwent awake craniotomy. All the patient went through intraoperative language mapping with the use of direct electrical stimulation. In order to map language production and comprehension modalities, in addition to the classical object naming task we used an additional task, the phonological judgment task. The results showed substantial dissociation between mapping of two tasks. According to these findings, we can conclude that the object naming task alone is not suitable for adequate brain mapping of the left temporal cortex. The same dissociation may be regarded as an argument in favor of the anatomical dissociation of the production and comprehension of speech in the left temporal cortex.

Electrocorticography (ECoG) language mapping is often performed extraoperatively, frequently involves offline processing, and relationships with direct cortical stimulation (DCS) remain variable. We sought to determine the feasibility and preliminary utility of an intraoperative language mapping approach guided by real-time visualization of electrocorticograms. A patient with astrocytoma underwent awake craniotomy with intraoperative language mapping, utilizing a dual iPad stimulus presentation system coupled to a real-time neural signal processing platform capable of both ECoG recording and delivery of DCS. Gamma band modulations in response to 4 language tasks at each electrode were visualized in real-time. Next, DCS was conducted for each neighboring electrode pair during language tasks. All language tasks resulted in strongest heat map activation at an electrode pair in the anterior to mid superior temporal gyrus. Consistent speech arrest during DCS was observed for Object and Action naming tasks at these same electrodes, indicating good correspondence with ECoG heat map recordings. This region corresponded well with posterior language representation via preoperative functional MRI. Intraoperative real-time visualization of language task-based ECoG gamma band modulation is feasible and may help identify targets for DCS. If validated, this may improve the efficiency and accuracy of intraoperative language mapping.

In order to identify the cortical areas involved in the reading process and to spare them during surgery, we systematically studied cortical areas by direct cortical stimulation in patients operated on for brain tumours. Seventy-six cortical stimulation mapping studies for language were performed in 35 monolingual and 19 bi- or multilingual patients over a 5-year period. We systematically searched for reading interference areas in addition to standard naming areas using an 'awake surgery' technique for brain mapping. A 'reading aloud' task (translated into different languages in multilingual patients) was used. Brain mapping was performed in left (44 patients) and right (10 patients) hemispheres. Cortical areas involved in reading were identified according to the type of interference, location and distinctness from naming areas. Stimulation of several major hemispheric regions resulted in significant interference with reading aloud: (i) the lower part of the pre- and postcentral gyri (P < 0.00001); (ii) the dominant supramarginal, angular and the posterior part of the superior temporal gyri (P < 0.00001); (iii) in the dominant inferior and middle frontal gyri (P < 0.001); and (iv) in the posterior part of the dominant middle temporal gyrus (P < 0.05). Interferences in reading were generally found in small cortical areas, with intervening areas evoking no reading interferences. Only partial overlap between reading and naming sites was found. Reading-specific sites were preferentially found when stimulating dominant inferior parietal or posterior temporal areas. Different types of reading interferences were noted. While 'articulatory' interferences were found in pre- and postcentral gyri bilaterally, and ocular-induced movements in bilateral middle frontal gyri, paraphasias were found mainly in the dominant supramarginal and posterior superior temporal gyri. Reading arrest sites were found in many regions. Reading interference sites were also occasionally found in the non-dominant hemisphere. In bilingual patients, if common cortical areas could be found, language- and reading-specific areas were sometimes detected, lending support to the concept that bilinguals can have relatively distinct cortical representation of their language skills. Finally, in this series, the location of reading interference sites and their relative specialization showed considerable individual variability.

See Hope and Price (doi:[10.1093/aww240][1]) for a scientific commentary on this article . Neurological insults that damage the left hemisphere are frequently associated with a variety of language disorders. Of these, lexical retrieval impairments are the most commonly observed, and often constitute the residual but lasting disturbance in patients with good functional outcomes. The current study was specifically designed to understand the anatomical factors that prevent full recovery of lexical retrieval in patients having undergone a neurosurgery for a left diffuse low-grade glioma, with a special focus on white matter disconnection. One hundred and ten patients operated on under local anaesthesia with intraoperative language mapping were included in this study. All benefited from an examination of language in the chronic phase using a picture-naming task. We derived from this task two well-controlled regressed measures of lexical retrieval based on the number of anomic responses and response times. We mapped the resection cavities and the postoperative residual lesion infiltrations (mainly located along the white matter tracts), and used a combination of voxelwise and tractwise lesion-deficit analyses to process the data. All results were corrected for multiple comparisons. For the purpose of comparison, 105 neurologically healthy control participants were further enrolled. At the cortical level, lexical retrieval impairments were mainly associated with resection of the mid-to-posterior part of the left inferior temporal gyrus, as revealed by standard voxel-based lesion–symptom analyses. Multilevel tractwise analyses, including correlations, ridge multiple regressions and group analyses, showed a strong involvement of the left inferior longitudinal fasciculus and, to a lesser extent, of the posterior superior longitudinal fasciculus. Further regression analyses indicated that lasting lexical retrieval impairments were better predicted by considering together both resection-related volume loss in the posterior inferior temporal gyrus and postoperative residual lesion volume in the left inferior longitudinal fasciculus. We conclude that the mid-to-posterior inferior temporal cortex and its underlying connections, especially the left inferior longitudinal fasciculus, are critical structures in the lexical retrieval network. Beyond this new insight, our data have important implications for both intraoperative language monitoring and rehabilitation strategies. * Abbreviations : DLGG : diffuse low-grade glioma IFOF : inferior fronto-occipital fasciculus ITG : inferior temporal gyrus ILF : inferior longitudinal fasciculus MTG : middle temporal gyrus Resid-anomia/TS/PS : standardized residuals from multiple regressions for the dependent variables anomia, total score and semantic paraphasia SLF : superior longitudinal fasciculus VLSM : voxel-based lesion-symptom mapping [1]: /lookup/doi/10.1093/brain/aww240

Simple SummaryLow-grade glioma (LGG) patients constitute an ideal in vivo pathological model to investigate cerebral neuroplasticity associated with major architectural disruption to the language network. Bilingual LGG patients offer a unique opportunity to study the neural capacity to negotiate L1 and L2 processing before and after the resection of critical language hubs. By combining the spatial resolution of fMRI with the temporal resolution and oscillatory information provided by MEG, we mapped the language network and its functional (re)organization in five Spanish–Basque bilingual patients. Both techniques provide converging evidence that different reshaping patterns occur for L1 and L2 after tumor resection. These changes affect not only language-specific nodes, but also areas associated with executive control mechanisms, underscoring the need for multilingual intraoperative approaches. Understanding neural (re)organization in the bilingual brain is crucial for preserving language function by means of personalized surgical interventions and rehabilitation strategies based on the patient’s linguistic profile.Recent evidence suggests that the presence of brain tumors (e.g., low-grade gliomas) triggers language reorganization. Neuroplasticity mechanisms called into play can transfer linguistic functions from damaged to healthy areas unaffected by the tumor. This phenomenon has been reported in monolingual patients, but much less is known about the neuroplasticity of language in the bilingual brain. A central question is whether processing a first or second language involves the same or different cortical territories and whether damage results in diverse recovery patterns depending on the language involved. This question becomes critical for preserving language areas in bilingual brain-tumor patients to prevent involuntary pathological symptoms following resection. While most studies have focused on intraoperative mapping, here, we go further, reporting clinical cases for five bilingual patients tested before and after tumor resection, using a novel multimethod approach merging neuroimaging information from fMRI and MEG to map the longitudinal reshaping of the language system. Here, we present four main findings. First, all patients preserved linguistic function in both languages after surgery, suggesting that the surgical intervention with intraoperative language mapping was successful in preserving cortical and subcortical structures necessary for brain plasticity at the functional level. Second, we found reorganization of the language network after tumor resection in both languages, mainly reflected by a shift of activity to right hemisphere nodes and the recruitment of ipsilesional left nodes. Third, we found that this reorganization varied according to the language involved, indicating that L1 and L2 follow different reshaping patterns after surgery. Fourth, oscillatory longitudinal effects were correlated with BOLD laterality changes in superior parietal and middle frontal areas. These findings may reflect that neuroplasticity impacts on the compensatory involvement of executive control regions, supporting the allocation of cognitive resources as a consequence of increased attentional demands. Furthermore, these results hint at the complementary role of this neuroimaging approach in language mapping, with fMRI offering excellent spatial localization and MEG providing optimal spectrotemporal resolution.

OBJECTIVE Determine the feasibility and preliminary utility of a novel approach to intraoperative brain mapping guided by visualization of electrocorticography (ECoG) heat maps. METHODS A 39-year-old male with a biopsy-proven left posterior temporal and occipital WHO grade II IDH-mutant astrocytoma underwent awake craniotomy with intraoperative language mapping. Language mapping utilized a dual iPad stimulus presentation system (NeuroMapper) coupled to a portable real-time neural signal processing system capable of both recording cortical activity and delivering direct cortical stimulation in a closed-loop fashion. An ECoG grid (4x8 with 1cm pitch) which covered the majority of the left temporal lobe was used to assess oscillatory cortical activity during administration of language paradigms including object, action, auditory descriptive, and written descriptive naming. ECoG recording and cortical stimulation were synchronized with stimulus presentation via a photosensor attached to the patient-facing tablet. Gamma band modulations in response to language paradigms at each electrode were processed in real-time and visualized as heat maps in MATLAB/Simulink. Following recording and visualization, bipolar direct cortical stimulation from the grid was conducted for each neighboring electrode pair (up to an intensity of 6 mA) during administration of language tasks. RESULTS Despite mild fluent aphasia, a large set of reliable baseline stimuli were obtained for the language mapping paradigms. All naming paradigms resulted in strongest heat map activation at electrode 12 located in the anterior to mid superior temporal gyrus. During stimulation, consistent speech arrest was observed across all paradigms when stimulating electrode pair 11-12, indicating good correspondence with ECoG heat map recordings. Additionally, this region corresponded well with posterior language network representation via resting-state fMRI. CONCLUSION Intraoperative real-time visualization of task-based ECoG gamma band modulation is feasible and may help identify targets for direct cortical stimulation. If validated, this may improve the efficiency and accuracy of intraoperative language mapping.

Standard versus tailored left temporal lobe resections: Differences in cognitive outcome?