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Intraoperative language and sensorimotor function mapping with direct electrical stimulation allows precise identification of functionally important brain regions. Direct electrical stimulation brain mapping has become the standard of care for the resection of brain lesions near or within eloquent regions with various patient outcome benefits. Intraoperative stimulation mapping (ISM) is commonly performed in an awake patient for language and motor assessments. However, motor mapping under general anesthesia, termed asleep motor mapping, has been increasingly performed over the last two decades for lesions primarily affecting the motor areas of the brain. Both asleep-awake-asleep and monitored anesthesia care have been successfully used for awake craniotomy in modern neuroanesthesia. Each anesthetic agent exerts varying effects on the quality of ISM, especially under general anesthesia. Careful selection of an anesthetic technique is crucial for the successful performance of ISM in both awake and asleep conditions. A comprehensive search was performed on electronic databases such as PubMed, Embase, Cochrane, Scopus, Web of Science, and Google Scholar to identify articles describing anesthesia for awake craniotomy, intraoperative brain mapping, and asleep motor mapping. In the second part of this narrative review, we summarize the effects of different anesthetic regimes and agents on ISM, causes of the failure of awake craniotomy and mapping, and outline the anesthetic considerations for ISM during awake craniotomy and asleep motor mapping.

Brain mapping has evolved tremendously in the past decade, fueled by advances in functional neuroimaging technology in neuro-oncology and epilepsy surgery. Despite this, wide anatomic-functional interindividual variability and intraoperative brain shift continue to challenge neurosurgeons performing surgery within or near eloquent brain regions. As such, intraoperative direct cortical and subcortical stimulation mapping remains the gold standard for localizing eloquent brain regions with precision for a safe and tailored resection. Intraoperative stimulation mapping (ISM) allows for maximizing the extent of resection while minimizing postoperative neurological deficits, resulting in better patient outcomes. Understanding the technical nuances of ISM is imperative for the anesthesiologist to provide better anesthetic management tailored to the surgery and stimulation mapping planned. A comprehensive search was performed on electronic databases to identify articles describing intraoperative cortical and subcortical mapping, language, and motor mapping. In the first part of this narrative review, we summarize the salient technical aspects of ISM and the common neurophysiological tasks assessed intraoperatively relevant to the anesthesiologist.

Intraoperative language and sensorimotor function mapping with direct electrical stimulation allows precise identification of functionally important brain regions. Direct electrical stimulation brain mapping has become the standard of care for the resection of brain lesions near or within eloquent regions with various patient outcome benefits. Intraoperative stimulation mapping (ISM) is commonly performed in an awake patient for language and motor assessments. However, motor mapping under general anesthesia, termed asleep motor mapping, has been increasingly performed over the last two decades for lesions primarily affecting the motor areas of the brain. Both asleep-awake-asleep and monitored anesthesia care have been successfully used for awake craniotomy in modern neuroanesthesia. Each anesthetic agent exerts varying effects on the quality of ISM, especially under general anesthesia. Careful selection of an anesthetic technique is crucial for the successful performance of ISM in both awake and asleep conditions. A comprehensive search was performed on electronic databases such as PubMed, Embase, Cochrane, Scopus, Web of Science, and Google Scholar to identify articles describing anesthesia for awake craniotomy, intraoperative brain mapping, and asleep motor mapping. In the second part of this narrative review, we summarize the effects of different anesthetic regimes and agents on ISM, causes of the failure of awake craniotomy and mapping, and outline the anesthetic considerations for ISM during awake craniotomy and asleep motor mapping. [ABSTRACT FROM AUTHOR]

Brain mapping has evolved tremendously in the past decade, fueled by advances in functional neuroimaging technology in neuro-oncology and epilepsy surgery. Despite this, wide anatomic-functional interindividual variability and intraoperative brain shift continue to challenge neurosurgeons performing surgery within or near eloquent brain regions. As such, intraoperative direct cortical and subcortical stimulation mapping remains the gold standard for localizing eloquent brain regions with precision for a safe and tailored resection. Intraoperative stimulation mapping (ISM) allows for maximizing the extent of resection while minimizing postoperative neurological deficits, resulting in better patient outcomes. Understanding the technical nuances of ISM is imperative for the anesthesiologist to provide better anesthetic management tailored to the surgery and stimulation mapping planned. A comprehensive search was performed on electronic databases to identify articles describing intraoperative cortical and subcortical mapping, language, and motor mapping. In the first part of this narrative review, we summarize the salient technical aspects of ISM and the common neurophysiological tasks assessed intraoperatively relevant to the anesthesiologist. [ABSTRACT FROM AUTHOR]

Simple Summary: Intraoperative stimulation mapping is a technique used to identify and preserve functional tissue during the surgical resection of gliomas. This form of functional brain mapping allows neurosurgeons to remove the most tumor tissue possible while minimizing the risk of a neurological deficit after surgery. The data supporting brain mapping and the technical nuances of performing these operations safely are described in this review. Gliomas are infiltrative primary brain tumors that often invade functional cortical and subcortical regions, and they mandate individualized brain mapping strategies to avoid postoperative neurological deficits. It is well known that maximal safe resection significantly improves survival, while postoperative deficits minimize the benefits associated with aggressive resections and diminish patients' quality of life. Although non-invasive imaging tools serve as useful adjuncts, intraoperative stimulation mapping (ISM) is the gold standard for identifying functional cortical and subcortical regions and minimizing morbidity during these challenging resections. Current mapping methods rely on the use of low-frequency and high-frequency stimulation, delivered with monopolar or bipolar probes either directly to the cortical surface or to the subcortical white matter structures. Stimulation effects can be monitored through patient responses during awake mapping procedures and/or with motor-evoked and somatosensory-evoked potentials in patients who are asleep. Depending on the patient's preoperative status and tumor location and size, neurosurgeons may choose to employ these mapping methods during awake or asleep craniotomies, both of which have their own benefits and challenges. Regardless of which method is used, the goal of intraoperative stimulation is to identify areas of non-functional tissue that can be safely removed to facilitate an approach trajectory to the equator, or center, of the tumor. Recent technological advances have improved ISM's utility in identifying subcortical structures and minimized the seizure risk associated with cortical stimulation. In this review, we summarize the salient technical aspects of which neurosurgeons should be aware in order to implement intraoperative stimulation mapping effectively and safely during glioma surgery. [ABSTRACT FROM AUTHOR]

Gliomas are one of the most common primary central nervous system tumors, and surgical treatment remains the principal role in the management of any grade of gliomas. In this study, based on the introduction of gliomas, we review the novel surgical techniques and technologies in support of the extent of resection to achieve long-term disease control and summarize the findings on how to keep the balance between cytoreduction and neurological morbidity from a list of literature searched. With modern neurosurgical techniques, gliomas resection can be safely performed with low morbidity and extraordinary longterm functional outcomes. [ABSTRACT FROM AUTHOR]

Background Mapping techniques are frequently used to preserve neurological function during glioma surgery. There is, however, no consensus regarding the use of many variables of these techniques. Currently, there are almost no objective data available about potential heterogeneity between surgeons and centers. The goal of this survey is therefore to globally identify, evaluate and analyze the local mapping procedures in glioma surgery. Methods The survey was distributed to members of the neurosurgical societies of the Netherlands (Nederlandse Vereniging voor Neurochirurgie—NVVN), Europe (European Association of Neurosurgical Societies—EANS), and the United States (Congress of Neurological Surgeons—CNS) between December 2020 and January 2021 with questions about awake mapping, asleep mapping, assessment of neurological morbidity, and decision making. Results Survey responses were obtained from 212 neurosurgeons from 42 countries. Overall, significant differences were observed for equipment and its settings that are used for both awake and asleep mapping, intraoperative assessment of eloquent areas, the use of surgical adjuncts and monitoring, anesthesia management, assessment of neurological morbidity, and perioperative decision making. Academic practices performed awake and asleep mapping procedures more often and employed a clinical neurophysiologist with telemetric monitoring more frequently. European neurosurgeons differed from US neurosurgeons regarding the modality for cortical/subcortical mapping and awake/asleep mapping, the use of surgical adjuncts, and anesthesia management during awake mapping. Discussion This survey demonstrates the heterogeneity among surgeons and centers with respect to their procedures for awake mapping, asleep mapping, assessing neurological morbidity, and decision making in glioma patients. These data invite further evaluations for key variables that can be optimized and may therefore benefit from consensus. [ABSTRACT FROM AUTHOR]

Gliomas are one of the most common primary central nervous system tumors, and surgical treatment remains the principal role in the management of any grade of gliomas. In this study, based on the introduction of gliomas, we review the novel surgical techniques and technologies in support of the extent of resection to achieve long-term disease control and summarize the findings on how to keep the balance between cytoreduction and neurological morbidity from a list of literature searched. With modern neurosurgical techniques, gliomas resection can be safely performed with low morbidity and extraordinary long-term functional outcomes., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Yang, Zhao, Zong, Piao, Zhao and Chen.)

Chinese processing has been suggested involving distinct brain areas from English. However, current functional localization studies on Chinese speech processing use mostly "indirect" techniques such as functional magnetic resonance imaging and electroencephalography, lacking direct evidence by means of electrocortical recording. In this study, awake craniotomies in 66 Chinese-speaking glioma patients provide a unique opportunity to directly map eloquent language areas. Intraoperative electrocortical stimulation was conducted and the positive sites for speech arrest, anomia, and alexia were identified separately. With help of stereotaxic neuronavigation system and computational modeling, all positive sites elicited by stimulation were integrated and a series of two- and three-dimension Chinese language probability maps were built. We performed statistical comparisons between the Chinese maps and previously derived English maps. While most Chinese speech arrest areas located at typical language production sites (i.e., 50% positive sites in ventral precentral gyrus, 28% in pars opercularis and pars triangularis), which also serve English production, an additional brain area, the left middle frontal gyrus (Brodmann's areas 6/9), was found to be unique in Chinese production (P < 0.05). Moreover, Chinese speakers' inferior ventral precentral gyrus (Brodmann's area 6) was used more than that in English speakers. Our finding suggests that Chinese involves more perisylvian region (extending to left middle frontal gyrus) than English. This is the first time that direct evidence supports cross-cultural neurolinguistics differences in human beings. The Chinese language atlas will also helpful in brain surgery planning for Chinese-speakers. [ABSTRACT FROM AUTHOR]

We used the method of direct electrostimulation combined with navigated tractography to map the frontal 'aslant' tract, enabling us to perform reliable anatomo-functional correlation in a patient undergoing awake surgery to remove a left frontal glioma. The findings enhanced our understanding of the organization of language within the human brain. [ABSTRACT FROM AUTHOR]

Background Music is one of the most sophisticated and fascinating functions of the brain. Yet, how music is instantiated within the brain is not fully characterized. Singing is a peculiar aspect of music, in which both musical and linguistic skills are required to provide a merged vocal output. Identifying the neural correlates of this process is relevant for both clinical and research purposes. Case Description An adult white man with a presumed left temporal glioma was studied. He is a professional opera singer. A tailored music evaluation, the Montreal Battery of Evaluation of Amusia, was performed preoperatively and postoperatively, with long-term follow-up. Intraoperative stimulation mapping (ISM) with awake surgery with a specific music evaluation battery was used to identify and preserve the cortical and subcortical structures subserving music, along with standard motor-sensory and language mapping. A total resection of a grade I glioma was achieved. The Montreal Battery of Evaluation of Amusia reported an improvement in musical scores after the surgery. ISM consistently elicited several types of errors in the superior temporal gyrus and, to a lesser extent, in the inferior frontal operculum. Most errors occurred during score reading; fewer errors were elicited during the assessment of rhythm. No spontaneous errors were recorded. These areas did not overlap with eloquent sites for counting or naming. Conclusions ISM and a tailored music battery enabled better characterization of a specific network within the brain subserving score reading independently from speech with long-term clinical impact. [ABSTRACT FROM AUTHOR]