Language Mapping Research Articles

Function-guided differences of arcuate fascicle and inferior fronto-occipital fascicle tractography as diagnostic indicators for surgical risk stratification.

Several patients with language-eloquent gliomas face language deterioration postoperatively. Persistent aphasia is frequently associated with damage to subcortical language pathways. Underlying mechanisms still need to be better understood, complicating preoperative risk assessment. This study compared qualitative and quantitative functionally relevant subcortical differences pre- and directly postoperatively in glioma patients with and without aphasia. Language-relevant cortical sites were defined using navigated transcranial magnetic stimulation (nTMS) language mapping in 74 patients between 07/2016 and 07/2019. Post-hoc nTMS-based diffusion tensor imaging tractography was used to compare a tract's pre- and postoperative visualization, volume and fractional anisotropy (FA), and the preoperative distance between tract and lesion and postoperative overlap with the resection cavity between the following groups: no aphasia (NoA), tumor- or previous resection induced aphasia persistent pre- and postoperatively (TIA_P), and surgery-induced transient or permanent aphasia (SIA_T or SIA_P). Patients with NoA, TIA_P, SIA_T, and SIA_P showed distinct fasciculus arcuatus (AF) and inferior-fronto-occipital fasciculus (IFOF) properties. The AF was more frequently reconstructable, and the FA of IFOF was higher in NoA than TIA_P cases (all p ≤ 0.03). Simultaneously, SIA_T cases showed higher IFOF fractional anisotropy than TIA_P cases (p < 0.001) and the most considerable AF volume loss overall. While not statistically significant, the four SIA_P cases showed complete loss of ventral language streams postoperatively, the highest resection-cavity-AF-overlap, and the shortest AF to tumor distance. Functionally relevant qualitative and quantitative differences in AF and IFOF provide a pre- and postoperative pathophysiological and clinically relevant diagnostic indicator that supports surgical risk stratification.

New stimulation procedures for language mapping in stereo-EEG.

Cortical intracerebral electrical stimulation is an important tool for language mapping in the presurgical work-up of patients with drug-resistant focal epilepsy. Language mapping with stereo-electroencephalography (EEG) is usually performed by high-frequency stimulations (HFS: 50 Hz), whereas low-frequency stimulations (LFS: 1 Hz) are usually considered useful for primary cortices mapping. Little is known in literature about "intermediate" frequencies (IFS: 6-15 Hz). Our objective is to explore the clinical usefulness of IFS in language mapping and identify factors, beyond the electrical parameters, that impact the mapping. We studied 23 patients submitted to stereo-EEG for presurgical evaluation. Language mapping was performed in the anterior, posterior and/or basal language region of the dominant hemisphere for language. We included all contact positions within these regions stimulated by HFS (50 Hz, 5 s, 1-3 mA) and IFS (6-15 Hz, 15 s, 5 mA). We compared the capability of both stimulation methods to induce a language deficit without afterdischarges (ADs), and we analyzed factors related to clinical examination, region, and stimulation technique by multivariate analysis. A total of 211 stimulations (98 HFS, 113 IFS) in 70 cortical sites within the anterior (84 stimulations), posterior (137), and basal language region (60) were included. IFS induced more frequently language deficits not associated to AD compared to HFS (37.1% vs 25.7%, p = .0043), whereas HFS provoked more diffuse AD (34.7% vs 15.0%, p = .001). Investigating multiple language functions increased the probability of revealing a deficit (odds ratio [OR] 3.16, p = .0016), independently of the stimulation method. IFS are valuable for language mapping, thereby improving the probability of inducing a clinical deficit not accompanied by an AD. The completeness of the clinical examination independently affects the sensitivity of the mapping. IFS are a new tool with potential usefulness for the cortical mapping of other associative cortical regions.

Awake brain mapping by direct cortical stimulation; technical note to get higher resection rate and low morbidity in low-grade glioma patients.

Direct cortical stimulation has been used for brain mapping and localization of eloquent areas in awake patients. This simplified technique is to provide the positive areas, which can be preserved if the tumor or lesions are involved eloquent areas. The main objective of this study is to determine whether direct cortical stimulation in awake brain mapping for low-grade glioma patients increases the rate of resection or not. The authors present a retrospective study between 2020 to 2022 that includes 35 cases in a single center, to get higher resection rate, and their consequences in awake craniotomy in low-grade glioma patients. Here, two neurosurgeons were involved and the minimum follow-up was 12 months. The authors achieved 80% removal of tumors. To get higher resection rate we emphasized negative mapping with prior anatomical analysis to understand functional realignment. Stimulation-related complications will be thoroughly discussed with a potential future direction to minimize the issues. The authors used PROMIS score to measure patients physical and mental health status and kernofsky score to measure performance status before and after successful surgery. The authors found three cases of transient deficit in repetitive stimulation. Repeated stimulation to identify the eloquent areas with low voltage frequency is a good option. Numbness in the face related to stimulation may continue for 6 weeks. Functional realignment in shifted brain and edema can be seen while doing cortical and subcortical stimulation. Most of the stimulation from low to high for language mapping may vary from patient to patient. For safe removal of low-grade glioma a steep learning curve is needed to find out the negative areas, though the authors emphasize positive mapping of areas to secure the maximum eloquence.

From Bilingualism to Multilingualism: Mapping Language Dynamics in the Linguistic Landscape of Hispanic Philadelphia

This study explores the linguistic landscape (LL) of three Hispanic neighborhoods in Philadelphia, PA, aiming to document and measure the presence of the Spanish language in public spaces and understand the influence of time, location, and establishment type on language use. Based on 3437 signs analyzed from 2021 to 2023, our findings reveal that English dominates the LL at 61.65%, while Spanish constitutes 24.16%. The study employs chi-squared tests to confirm the impact of time and location on language use, highlighting a rise in bilingual and monolingual Spanish signs over time. Additionally, variables were combined into clusters using a heatmap to explore language use across different establishments. Bilingualism emerges as a sustained trend, underscoring inclusivity and linguistic diversity within these contexts. Location analysis exposes unique linguistic characteristics in each neighborhood, reflecting the cultural and linguistic diversity of their communities. The Golden Block exhibits bilingual prevalence, indicative of evolving demographics. Olney showcases language mixtures due to diverse ethnic and sociolinguistic influences, while South Philadelphia’s Italian Market area features prevalent Spanish and multilingual signage. The study underscores the growing presence of Spanish and minority languages, emphasizing the need to recognize and revitalize linguistic diversity in urban spaces. As cities evolve, continued exploration of the LL is crucial to understanding language dynamics in relation to identity, culture, and power.

Concordance between Wada, Transcranial Magnetic Stimulation, and Magnetoencephalography for Determining Hemispheric Dominance for Language: A Retrospective Study

Determination of language hemispheric dominance (HD) in patients undergoing evaluation for epilepsy surgery has traditionally relied on the sodium amobarbital (Wada) test. The emergence of non-invasive methods for determining language laterality has increasingly shown to be a viable alternative. In this study, we assessed the efficacy of transcranial magnetic stimulation (TMS) and magnetoencephalography (MEG), compared to the Wada test, in determining language HD in a sample of 12 patients. TMS-induced speech errors were classified as speech arrest, semantic, or performance errors, and the HD was based on the total number of errors in each hemisphere with equal weighting of all errors (classic) and with a higher weighting of speech arrests and semantic errors (weighted). Using MEG, HD for language was based on the spatial extent of long-latency activity sources localized to receptive language regions. Based on the classic and weighted language laterality index (LI) in 12 patients, TMS was concordant with the Wada in 58.33% and 66.67% of patients, respectively. In eight patients, MEG language mapping was deemed conclusive, with a concordance rate of 75% with the Wada test. Our results indicate that TMS and MEG have moderate and strong agreement, respectively, with the Wada test, suggesting they could be used as non-invasive substitutes.

Empowering the SDM-RDFizer tool for scaling up to complex knowledge graph creation pipelines1

The significant increase in data volume in recent years has prompted the adoption of knowledge graphs as valuable data structures for integrating diverse data and metadata. However, this surge in data availability has brought to light challenges related to standardization, interoperability, and data quality. Knowledge graph creation faces complexities from large data volumes, data heterogeneity, and high duplicate rates. This work addresses these challenges and proposes data management techniques to scale up the creation of knowledge graphs specified using the RDF Mapping Language (RML). These techniques are integrated into SDM-RDFizer, transforming it into a two-fold solution designed to address the complexities of generating knowledge graphs. Firstly, we introduce a reordering approach for RML triples maps, prioritizing the evaluation of the most selective maps first to reduce memory usage. Secondly, we employ an RDF compression strategy, along with optimized data structures and novel operators, to prevent the generation of duplicate RDF triples and optimize the execution of RML operators. We assess the performance of SDM-RDFizer through established benchmarks. The evaluation showcases the effectiveness of SDM-RDFizer compared to state-of-the-art RML engines, emphasizing the benefits of our techniques. Furthermore, the paper presents real-world projects where SDM-RDFizer has been utilized, providing insights into the advantages of declaratively defining knowledge graphs and efficiently executing these specifications using this engine.

Geographical Effect against Linguistic Landscape on Coffee Shop Signboards in West Padang Subdistrict

Language mapping is a new perspective in a linguistic landscape as a novelty of this research. This research described the variation and domination of language use on coffee shop signboards through language mapping and analyzed how the geographical situation and conditions can affect the use of that language. There were 60 coffee shop signboards in the West Sumatra Subdistrict, which is divided into three regions: the city center, taplau, and pondok cino (China town), which became the data population of this research. Several data were selected using random sampling to analyze the reason for language use based on geographical conditions or situations. The research uses qualitative methods to collect data and analyze results using GIS (Geographic Information Systems) and Adobe Photoshop. Using the two software as instruments is an innovation in the method of the linguistic landscape (LL). The analysis began with quantifying language usage, including monolingual, bilingual, and multilingual forms on coffee shop signboards. Subsequently, language mapping was conducted to illustrate language variation and highlight linguistic dominance in specific areas. Finally, the study delved into the rationale behind language selection, considering geographical conditions and situational context evident in the language mapping. Findings revealed the presence of 12 languages on coffee shop signage, including Indonesian, Minangkabau, Javanese, English, Arabic, Dutch, Italian, Japanese, Korean, French, Spanish and Chinese. The use of foreign languages was attributed to global influences and societal preferences for modernization and prestige. Moreover, the research underscored the influence of geographical conditions and situational context on linguistic landscapes, impacting shop naming, cultural identity, and commercial objectives within a region.

Noninvasive- and invasive mapping reveals similar language network centralities – A function-based connectome analysis

BackgroundFormer comparisons between direct cortical stimulation (DCS) and navigated transcranial magnetic stimulation (nTMS) only focused on cortical mapping. While both can be combined with diffusion tensor imaging, their differences in the visualization of subcortical and even network levels remain unclear. Network centrality is an essential parameter in network analysis to measure the importance of nodes identified by mapping. Those include Degree centrality, Eigenvector centrality, Closeness centrality, Betweenness centrality, and PageRank centrality. While DCS and nTMS have repeatedly been compared on the cortical level, the underlying network identified by both has not been investigated yet. Method27 patients with brain lesions necessitating preoperative nTMS and intraoperative DCS language mapping during awake craniotomy were enrolled. Function-based connectome analysis was performed based on the cortical nodes obtained through the two mapping methods, and language-related network centralities were compared. ResultsCompared with DCS language mapping, the positive predictive value of cortical nTMS language mapping is 74.1%, with good consistency of tractography for the arcuate fascicle and superior longitudinal fascicle. Moreover, network centralities did not differ between the two mapping methods. However, ventral stream tracts can be better traced based on nTMS mappings, demonstrating its strengths in acquiring language-related networks. In addition, it showed lower centralities than other brain areas, with decentralization as an indicator of language function loss. ConclusionThis study deepens the understanding of language-related functional anatomy and proves that non-invasive mapping-based network analysis is comparable to the language network identified via invasive cortical mapping.

Timing and location of speech errors induced by direct cortical stimulation.

Cortical regions supporting speech production are commonly established using neuroimaging techniques in both research and clinical settings. However, for neurosurgical purposes, structural function is routinely mapped peri-operatively using direct electrocortical stimulation. While this method is the gold standard for identification of eloquent cortical regions to preserve in neurosurgical patients, there is lack of specificity of the actual underlying cognitive processes being interrupted. To address this, we propose mapping the temporal dynamics of speech arrest across peri-sylvian cortices by quantifying the latency between stimulation and speech deficits. In doing so, we are able to substantiate hypotheses about distinct region-specific functional roles (e.g. planning versus motor execution). In this retrospective observational study, we analysed 20 patients (12 female; age range 14-43) with refractory epilepsy who underwent continuous extra-operative intracranial EEG monitoring of an automatic speech task during clinical bedside language mapping. Latency to speech arrest was calculated as time from stimulation onset to speech arrest onset, controlling for individual speech rate. Most instances of motor-based arrest (87.5% of 96 instances) were in sensorimotor cortex with mid-range latencies to speech arrest with a distributional peak at 0.47 s. Speech arrest occurred in numerous regions, with relatively short latencies in supramarginal gyrus (0.46 s), superior temporal gyrus (0.51 s) and middle temporal gyrus (0.54 s), followed by relatively long latencies in sensorimotor cortex (0.72 s) and especially long latencies in inferior frontal gyrus (0.95 s). Non-parametric testing for speech arrest revealed that region predicted latency; latencies in supramarginal gyrus and in superior temporal gyrus were shorter than in sensorimotor cortex and in inferior frontal gyrus. Sensorimotor cortex is primarily responsible for motor-based arrest. Latencies to speech arrest in supramarginal gyrus and superior temporal gyrus (and to a lesser extent middle temporal gyrus) align with latencies to motor-based arrest in sensorimotor cortex. This pattern of relatively quick cessation of speech suggests that stimulating these regions interferes with the outgoing motor execution. In contrast, the latencies to speech arrest in inferior frontal gyrus and in ventral regions of sensorimotor cortex were significantly longer than those in temporoparietal regions. Longer latencies in the more frontal areas (including inferior frontal gyrus and ventral areas of precentral gyrus and postcentral gyrus) suggest that stimulating these areas interrupts a higher-level speech production process involved in planning. These results implicate the ventral specialization of sensorimotor cortex (including both precentral and postcentral gyri) for speech planning above and beyond motor execution.

Dissociation of reading and naming in ventral occipitotemporal cortex.

Lesions in language-dominant ventral occipitotemporal cortex (vOTC) can result in selective impairment of either reading and naming, resulting in alexia or anomia. Yet, functional imaging studies that show differential activation for naming and reading do not reveal activity exclusively tuned to one of these inputs. To resolve this dissonance in the functional architecture of vOTC, we used focused stimulation to the vOTC in 49 adult patients during reading and naming, and generated a population-level, probabilistic map to evaluate if reading and naming are clearly dissociable within individuals. Language mapping (50 Hz, 2,829 stimulations) was performed during passage reading (216 positive sites) and visual naming (304 positive sites). Within vOTC we isolated sites that selectively disrupted reading (24 sites, 11 patients) or naming (27 sites in 12 patients), and those that disrupted both processes (75 sites in 21 patients). The anteromedial vOTC had a higher probability of producing naming disruption while posterolateral regions resulted in greater reading specific disruption. Between them lay a multi-modal region where stimulation disrupted both reading and naming. This work provides a comprehensive view of vOTC organization - the existence of heteromodal cortex critical to both reading and naming, along with causally dissociable unimodal naming cortex, and a reading-specific visual word form area in vOTC. Their distinct roles as associative regions may thus relate to their connectivity within the broader language network that is disrupted by stimulation, more than to highly selective tuning properties. Our work also implies that pre-surgical mapping of both reading and naming is essential for patients requiring vOTC resections, as these functions are not co-localized and such mapping may prevent the occurrence of unexpected deficits.

An ontological approach for representing declarative mapping languages

Knowledge Graphs are currently created using an assortment of techniques and tools: ad hoc code in a programming language, database export scripts, OpenRefine transformations, mapping languages, etc. Focusing on the latter, the wide variety of use cases, data peculiarities, and potential uses has had a substantial impact in how mappings have been created, extended, and applied. As a result, a large number of languages and their associated tools have been created. In this paper, we present the Conceptual Mapping ontology, that is designed to represent the features and characteristics of existing declarative mapping languages to construct Knowledge Graphs. This ontology is built upon the requirements extracted from experts experience, a thorough analysis of the features and capabilities of current mapping languages presented as a comparative framework; and the languages’ limitations discussed by the community and denoted as Mapping Challenges. The ontology is evaluated to ensure that it meets these requirements and has no inconsistencies, pitfalls or modelling errors, and is publicly available online along with its documentation and related resources.

Impact of function-guided glioma treatment on oncological outcome in the elderly

IntroductionMany patients with high-grade gliomas (HGG) are of older age. Research questionWe hypothesize that pre- and intraoperative mapping and monitoring preserve functional status in elderly patients while gross total resection (GTR) is the aim, resulting in overall survival (OS) rates comparable to the general population with HGG. Material and methodsWe subdivided a prospective cohort of 168 patients above 65 years with eloquent high-grade gliomas into four groups ([years/cases] 1: 65–69/58; 2: 70–74/47; 3: 75–79/43; 4: >79/20). All patients underwent preoperative noninvasive mapping, which was also used for decision-making, intraoperative neuromonitoring in 138 cases, direct cortical and/or subcortical motor mapping in 66 and 50 cases, and awake language mapping in 11 cases. ResultsGTR and subtotal resection (STR) could be achieved in 65% and 28%, respectively. Stereotactic biopsy was performed in 8% of cases. Postoperatively, we found transient and permanent functional deficits in 13% and 11% of cases. Postoperative Karnofsky Performance Scale (KPS) did not differ between subgroups. Patients with long-term follow-up (51%) had a progression-free survival of 5.5 (1–47) months and an overall survival of 10.5 (0–86) months. Discussion and conclusionThe interdisciplinary glioma treatment in the elderly is less age-dependent but must be adjusted to the functional status. Function-guided surgical resections could be performed as usual, with maximal tumor resection being the primary goal. However, less network capacity in the elderly to compensate for deficits might cause higher rates of permanent deficits in this group of patients with more fast-growing malignant gliomas.

Recommended Resting-State fMRI Acquisition and Preprocessing Steps for Preoperative Mapping of Language and Motor and Visual Areas in Adult and Pediatric Patients with Brain Tumors and Epilepsy.

Resting-state (rs) fMRI has been shown to be useful for preoperative mapping of functional areas in patients with brain tumors and epilepsy. However, its lack of standardization limits its widespread use and hinders multicenter collaboration. The American Society of Functional Neuroradiology, American Society of Pediatric Neuroradiology, and the American Society of Neuroradiology Functional and Diffusion MR Imaging Study Group recommend specific rs-fMRI acquisition approaches and preprocessing steps that will further support rs-fMRI for future clinical use. A task force with expertise in fMRI from multiple institutions provided recommendations on the rs-fMRI steps needed for mapping of language, motor, and visual areas in adult and pediatric patients with brain tumor and epilepsy. These were based on an extensive literature review and expert consensus.Following rs-fMRI acquisition parameters are recommended: minimum 6-minute acquisition time; scan with eyes open with fixation; obtain rs-fMRI before both task-based fMRI and contrast administration; temporal resolution of ≤2 seconds; scanner field strength of 3T or higher. The following rs-fMRI preprocessing steps and parameters are recommended: motion correction (seed-based correlation analysis [SBC], independent component analysis [ICA]); despiking (SBC); volume censoring (SBC, ICA); nuisance regression of CSF and white matter signals (SBC); head motion regression (SBC, ICA); bandpass filtering (SBC, ICA); and spatial smoothing with a kernel size that is twice the effective voxel size (SBC, ICA).The consensus recommendations put forth for rs-fMRI acquisition and preprocessing steps will aid in standardization of practice and guide rs-fMRI program development across institutions. Standardized rs-fMRI protocols and processing pipelines are essential for multicenter trials and to implement rs-fMRI as part of standard clinical practice.

Early access to language supports number mapping skills in deaf children.

The ability to associate different types of number representations referring to the same quantity (symbolic Arabic numerals, signed/spoken number words, and nonsymbolic quantities), is an important predictor of overall mathematical success. This foundational skill-mapping-has not been examined in deaf and hard-of-hearing (DHH) children. To address this gap, we studied 188 4 1/2 to 9-year-old DHH and hearing children and systematically examined the relationship between their language experiences and mapping skills. We asked whether the timing of children's language exposure (early vs. later), the modality of their language (signed vs. spoken), and their rote counting abilities related to mapping performance. We found that language modality did not significantly relate to mapping performance, but timing of language exposure and counting skills did. These findings suggest that early access to language, whether spoken or signed, supports the development of age-typical mapping skills and that knowledge of number words is critical for this development.

CompreTAP: Feasibility and reliability of a new language comprehension mapping task via preoperative navigated transcranial magnetic stimulation

ObjectiveStimulation-based language mapping approaches that are used pre- and intraoperatively employ predominantly overt language tasks requiring sufficient language production abilities. Yet, these production-based setups are often not feasible in brain tumor patients with severe expressive aphasia. This pilot study evaluated the feasibility and reliability of a newly developed language comprehension task with preoperative navigated transcranial magnetic stimulation (nTMS). MethodsFifteen healthy subjects and six brain tumor patients with severe expressive aphasia unable to perform classic overt naming tasks underwent preoperative nTMS language mapping based on an auditory single-word Comprehension TAsk for Perioperative mapping (CompreTAP). Comprehension was probed by button-press responses to auditory stimuli, hence not requiring overt language responses. Positive comprehension areas were identified when stimulation elicited an incorrect or delayed button press. Error categories, case-wise cortical error rate distribution and inter-rater reliability between two experienced specialists were examined. ResultsOverall, the new setup showed to be feasible. Comprehension-disruptions induced by nTMS manifested in no responses, delayed or hesitant responses, searching behavior or selection of wrong target items across all patients and controls and could be performed even in patients with severe expressive aphasia. The analysis agreement between both specialists was substantial for classifying comprehension-positive and -negative sites. Extensive left-hemispheric individual cortical comprehension sites were identified for all patients. Apart from one case presenting with transient worsening of aphasic symptoms, pre-existing language deficits did not aggravate if results were used for subsequent surgical planning. ConclusionEmploying this new comprehension-based nTMS setup allowed to identify language relevant cortical sites in all healthy subjects and severely aphasic patients who were thus far precluded from classic production-based mapping. This pilot study, moreover, provides first indications that the CompreTAP mapping results may support the preservation of residual language function if used for subsequent surgical planning.

Mind mapping in foreign language classes: review of online mind map constructors

The article deals with the peculiarities of the educational technology of mind mapping, reviews several digital applications for creating mind maps, and practically proves the effectiveness of using mind mapping in foreign language classes.The digitization of the educational process, the globalization of knowledge and the availability of educational information arrays, in combination with quarantine restrictions and the war in Ukraine, have presented significant obstacles to foreign language teachers. Although mind mapping technology is relatively new, it has many supporters among linguists. The essence of educational technology based on compliance with the radial type of brain perception of an array of information, which is more natural than linear, is analysed in detail in the article. The appropriate systematicity, structure, simplicity and adaptability of this method of material demonstration, in contrast to the traditional ones, were delivered through the characterization of the main elements of the mental map structure and the basic rules for its creation. The paper provides an overview of three primary online mind map constructors (Gitmind, Mindomo, and Coggle) according to several requirements, adequate for teaching foreign language grammar to first-year students majoring in “Philology”. Based on the review of the basic and target characteristics of mind map applications, the article’s authors recommended the Gitmind constructor and justified the choice. An example of the practical application of mental maps and the application in foreign language classes was also presented in the article. The stages of creating a teaching mind map for presenting a grammar topic were described. The article presents the results of the final survey of students involved in learning with the help of mind maps, which proved the expediency and effectiveness of using mind maps in teaching foreign languages in general, and the optimality of using a digital mind map constructor in particular.

NIMG-63. GAMMA-BAND MODULATIONS OF ELECTROCORTICOGRAM (ECOG) INDUCED BY COGNITIVE-LINGUISTIC TASKS DURING AWAKE CRANIOTOMY FOR FEASIBLE FUNCTIONAL LANGUAGE MAPPING

Abstract INTRODUCTION Intraoperative functional language mapping has uncertainty in predicting language function and post-surgical outcomes. We study the feasibility of functional mapping using electrocorticogram (ECoG) gamma-band modulations induced by linguistic tasks having different complexity levels. METHODS Five subjects with left temporal lobe glioma underwent resection involving awake language mapping using a 4x8 ECoG electrode grid. A MATLAB/Simulink based real-time software system was used to map task-induced gamma-band modulations as 2D heat maps. Tasks included verbally responding to single word/tone categorization; object, action, written descriptive and auditory naming respectively. Auditory stimuli were provided during word/tone categorization (duration 300~500ms) and auditory naming tasks ( &amp;gt; 1s). Other tasks provided visual stimuli (line drawings or written phrases). Bipolar DCS (2~6 mA, 60Hz, 2s) was applied at different electrode pairs while repeating the naming tasks. RESULTS Cortical regions activated by word stimuli and the auditory naming task were similar; superior, middle temporal gyri (STG, MTG). Visual naming tasks modulated posterior MTG (pMTG) and STG (written naming). Reproducible speech arrests occurred during different naming tasks while stimulating specific electrode pairs, even though not all electrodes had strong task-specific activations. Considerable inter-personal variability of language areas identified with DCS was observed, despite the similarity of task-specific gamma-band modulated regions across subjects. Post-operative decline in language score was observed in one subject, with resection boundary covering gamma modulated regions during auditory processing tasks but no DCS identified region. CONCLUSION Intraoperative language mapping guided by gamma-band ECoG modulations induced by simple word/tone categorization task exhibited similar patterns to more complex naming tasks, suggesting this task may be a viable approach to localize functional cortex, especially in patients unable to reliably perform more difficult paradigms. Utilizing this method in conjunction with DCS mapping guided by visual naming tasks, eloquent cortical language areas may be better preserved reducing post-operative language deficits.

CNSC-22. CANCER NEUROSCIENCE IN THE OR: ELECTROPHYSIOLOGIC INSIGHTS AT THE TIME OF BRAIN TUMOR RESECTION

Abstract Pioneering works by Venkatesh and Venkataramani demonstrated that formation of functional neural-glial synapses fosters development and growth of glial neoplasms. Resultant peritumoral neural hyperexcitability associates with tumor progression, though limited in vivo human data have been evaluated to date. We sought to enrich our understanding of these mechanisms by obtaining thin film intraoperative micro-electrocorticography (µECoG) recordings from patients undergoing primary brain tumor resection. METHODS: Intraoperative µECoG data for 8 patients with low- (LGG) and high-grade glioma (HGG, WHO grades 3 and 4) of various tumor histology were included. Analyses excluded any operative behavioral or cognitive tasks and evaluated data prior to stimulation for language or motor mapping. Following low pass (&amp;lt; 200 Hz) and notch filtering at 60, 120, and 180 Hz for ambient electrical noise, bandpower was calculated using multitaper spectral analysis for low frequency (LF, &amp;lt; 1 Hz), delta (1-4 Hz), beta (12-30 Hz), gamma (30-80 Hz), and high gamma (80-200 Hz) bands. RESULTS: Compared to isocitrate dehydrogenase (IDH) wild-type tumors, those with IDH-mutation (n = 3; two WHO grade 3, one grade 4) demonstrated the highest proportion of power within the LF band (92.2% vs 71.4%) with relatively lower proportional beta (3.6% vs 18.3%) and gamma (2.2% vs 8.7%) bandpower. The same pattern was seen in HGG (n = 5) vs LGG (n = 3) tumors with higher LF (84.5% vs 70.3%) and lower beta (10.3% vs 16.8%) and gamma (3.5% vs 10.8%) bandpower, perhaps driven by three HGGs with IDH mutation. Absolute bandpower was highest at all bands in a patient with left frontal glioblastoma. CONCLUSIONS: Interesting patterns are emerging that corroborate differential high and low frequency neural activity among patients with primary brain tumors. Disparities in LF and beta/gamma bands may represent therapeutic targets or a non-invasive biomarker of disease activity but require further, ongoing data collection and analyses.

Functional Magnetic Resonance Imaging and Diffusion Tensor Imaging-Tractography in Resective Brain Surgery: Lesion Coverage Strategies and Patient Outcomes.

Diffusion tensor imaging (DTI)-tractography and functional magnetic resonance imaging (fMRI) have dynamically entered the presurgical evaluation context of brain surgery during the past decades, providing novel perspectives in surgical planning and lesion access approaches. However, their application in the presurgical setting requires significant time and effort and increased costs, thereby raising questions regarding efficiency and best use. In this work, we set out to evaluate DTI-tractography and combined fMRI/DTI-tractography during intra-operative neuronavigation in resective brain surgery using lesion-related preoperative neurological deficit (PND) outcomes as metrics. We retrospectively reviewed medical records of 252 consecutive patients admitted for brain surgery. Standard anatomical neuroimaging protocols were performed in 127 patients, 69 patients had additional DTI-tractography, and 56 had combined DTI-tractography/fMRI. fMRI procedures involved language, motor, somatic sensory, sensorimotor and visual mapping. DTI-tractography involved fiber tracking of the motor, sensory, language and visual pathways. At 1 month postoperatively, DTI-tractography patients were more likely to present either improvement or preservation of PNDs (p = 0.004 and p = 0.007, respectively). At 6 months, combined DTI-tractography/fMRI patients were more likely to experience complete PND resolution (p < 0.001). Low-grade lesion patients (N = 102) with combined DTI-tractography/fMRI were more likely to experience complete resolution of PNDs at 1 and 6 months (p = 0.001 and p < 0.001, respectively). High-grade lesion patients (N = 140) with combined DTI-tractography/fMRI were more likely to have PNDs resolved at 6 months (p = 0.005). Patients with motor symptoms (N = 80) were more likely to experience complete remission of PNDs at 6 months with DTI-tractography or combined DTI-tractography/fMRI (p = 0.008 and p = 0.004, respectively), without significant difference between the two imaging protocols (p = 1). Patients with sensory symptoms (N = 44) were more likely to experience complete PND remission at 6 months with combined DTI-tractography/fMRI (p = 0.004). The intraoperative neuroimaging modality did not have a significant effect in patients with preoperative seizures (N = 47). Lack of PND worsening was observed at 6 month follow-up in patients with combined DTI-tractography/fMRI. Our results strongly support the combined use of DTI-tractography and fMRI in patients undergoing resective brain surgery for improving their postoperative clinical profile.

Improving specificity of stimulation-based language mapping in stuttering glioma patients: A mixed methods serial case study

ObjectiveStimulation-based language mapping relies on identifying stimulation-induced language disruptions, which preexisting speech disorders affecting the laryngeal and orofacial speech system can confound. This study ascertained the effects of preexisting stuttering on pre- and intraoperative language mapping to improve the reliability and specificity of established language mapping protocols in the context of speech fluency disorders. MethodDifferentiation-ability of a speech therapist and two experienced nrTMS examiners between stuttering symptoms and stimulation-induced language errors during preoperative mappings were retrospectively compared (05/2018-01/2021). Subsequently, the impact of stuttering on intraoperative mappings was evaluated in all prospective patients (01/2021-12/2022). ResultsIn the first part, 4.85 % of 103 glioma patients stuttered. While both examiners had a significant agreement for misclassifying pauses in speech flow and prolongations (Κ ≥ 0.50, p ≤ 0.02, respectively), less experience resulted in more misclassified stuttering symptoms. In one awake surgery case within the second part, stuttering decreased the reliability of intraoperative language mapping.Comparison with Existing Method(s): By thoroughly differentiating speech fluency symptoms from stimulation-induced disruptions, the reliability and proportion of stuttering symptoms falsely attributed to stimulation-induced language network disruptions can be improved. This may increase the consistency and specificity of language mapping results in stuttering glioma patients. ConclusionsPreexisting stuttering negatively impacted language mapping specificity. Thus, surgical planning and the functional outcome may benefit substantially from thoroughly differentiating speech fluency symptoms from stimulation-induced disruptions by trained specialists.