Electrophysiological Monitoring Research Articles

SURG-23. ESTABLISHMENT OF AN APPROPRIATE GLIOMA SURGERY SYSTEM CONSIDERING MOLECULAR AND FUNCTIONAL BOUNDARIES

Abstract Gliomas are invasive tumors and cannot be cured by surgery. But surgical removal has also been proven to affect treatment outcomes. Recent advances in molecular diagnostics have identified IDH mutations, especially in lower grade gliomas, allowing the identification of so-called molecular boundaries. It is conceivable that expanded resection to the molecular border may improve treatment outcome. On the other hand, extended resection may be incompatible with functional preservation. In such cases, it is also important to consider that the impact of surgery on treatment outcome has also been proven to vary by glioma genotype. While total resection has a significant prognostic impact on survival in astrocytomas with IDH mutations, the impact on survival in oligodendrogliomas that are sensitive to chemoradiotherapy and, conversely, in high-grade tumors without IDH mutations is lower than in the former. Therefore, it is important to determine the extent of removal after considering the tumor type. In general, various surgical support devices such as surgical navigation systems, fluorescent diagnosis using 5ALA, intraoperative electrophysiological monitoring, awake functional brain mapping, and intraoperative MRI are applied during glioma surgery. In addition to these, we have developed a surgical system that also focuses on tumor subtypes by introducing preoperative tumor type prediction using AI imaging and intraoperative rapid genetic diagnosis. We have further developed intraoperative rapid genetic diagnosis to identify genetic mutations around the tumor, enabling the detection of molecular boundaries. It is now possible to remove as much as possible, considering the molecular boundary, while paying sufficient attention to preservation of brain functions. Gliomas are intractable diseases, but their treatment outcomes have steadily improved over time. We are now in an era of a tailor-made surgery based on a variety of data. Implementing “appropriate surgical procedures” we aim at further improvement of treatment outcomes.

Continuous QTc monitoring for patients intoxicated with QTc prolonging medication in the ED: a proof of principle.

Background: To determine when patients presenting with an overdose of QT-interval prolonging drugs can be discharged safely can be challenging, especially when the moment of intoxication and/or the substance(s) ingested are unknown. Objective: In a proof of principle study, we aimed to study if continuous QTc interval analysis can be used to establish optimal observation duration of patients with an intoxication with QTc prolonging medication. Methods: For patients presenting with an intoxication with QT-interval prolonging drugs in the emergency department (ED), ECG signals sampled at 500Hz were pre-processed, and the average heart rate corrected QT-interval (QTc) per 5 minutes was calculated and plotted against time. A third order polynomial was fitted to visualize when the QTc would be highest (the electrophysiological Tmax). This point in time was compared to the estimated Tmax based on pharmacokinetic properties of the ingested substance. Results: In a retrospective biobank-based study, a total of 22 ED visits (of 15 patients) were analyzed. An electrophysiological Tmax could be calculated for 17/22 visits. The remaining five patients presented either long after the electrophysiological Tmax (n=4) or were admitted to the ward before reaching the Tmax (n=1). The average (SD) difference between the estimated Tmax based on drug properties and the calculated electrophysiological Tmax was 18 (133) minutes (range -158-296 minutes). Despite the wide range, there was a significant correlation between recorded electrophysiological Tmax and estimated Tmax (r=0.67, p=0.012). Conclusion: Continuous electrophysiological monitoring can be used as an adjunct to determine the toxicokinetic Tmax for patients presenting with an intoxication, especially when the time of ingestion or the substance ingested are unknown.

Simultaneous Optical and Electrophysiological Monitoring of Neuronal Cells in Brain Slices

Simultaneous Optical and Electrophysiological Monitoring of Neuronal Cells in Brain Slices

Uyanık Kraniyotomide Anestezi Yönetimi

Performing craniotomy on patients while they are “awake” requires a very specific anesthesia management. It is the anesthetist’s responsibility to apply sedation and analgesia when necessary to ensure optimal comfort of the patient during the surgery, and to continue electrophysiological monitoring and patient cooperation. In addition to specific anesthesia management, good teamwork, where communication is very important, is an absolute necessity for the awake craniotomy procedure. The aim of this review is to discuss in detail the different anesthesia techniques that can be applied during awake craniotomy and the intraoperative complications that may develop. Keywords: Awake craniotomy, anesthetic management, complications

Simultaneous Optical and Electrophysiological Monitoring of Neuronal Cells in Brain Slices

Simultaneous Optical and Electrophysiological Monitoring of Neuronal Cells in Brain Slices

Paintable, Fast Gelation, Highly Adhesive Hydrogels for High-fidelity Electrophysiological Monitoring Wirelessly.

High-fidelity wireless electrophysiological monitoring is essential for ambulatory healthcare applications. Soft solid-like hydrogels have received significant attention as epidermal electrodes because of their tissue-like mechanical properties and high biocompatibility. However, it is challenging to develop a hydrogel electrode that provides robust contact and high adhesiveness with glabrous skin and hairy scalp for high-fidelity, continuous electrophysiological signal detection. Here, a paintable, fast gelation, highly adhesive, and conductive hydrogel is engineered for high-fidelity wireless electrophysiological monitoring. The hydrogel, consisting of gelatin, gallic acid, sodium citrate, lithium chloride, glycerol, and Tris-HCl buffer solution exhibits a reversible thermal phase transition capability, which endows it with the attributes of on-skin applicability and fast in situ gelation with 15 s, thereby addressing the aforementioned limitations. The introduction of gallic acid enhances the adhesive properties of the hydrogel, facilitating secure electrode attachment to the skin or hairy scalp. To accentuate the potential applications in at-home electrophysiological health monitoring, the hydrogel electrodes are demonstrated for high-fidelity electrocardiogram recording for one hour during various daily activities, as well as in simultaneous electroencephalogram and electrocardiogram recording during a 30 min nap.

Intraoperative changes in electrophysiological monitoring can be used to predict clinical outcomes in patients with spinal cavernous malformation.

The study aimed to evaluate the sensitivity and specificity of these monitoring parameters in predicting postoperative neurological dysfunction. In this study, a total of 85 patients with spinal cavernous malformations (SCMs) treated at Xuanwu Hospital, Capital Medical University, from November 2012 to August 2017 were included. During the surgical procedures, all patients underwent monitoring of motor evoked potentials (MEP) and somatosensory evoked potentials (SEP). The criteria for warning included a reduction of ≥80% in MEP amplitude and ≥50% in SEP amplitude. Among 85 patients, 40 (47.1%) had SCMs located in the thoracic segment, 35 (41.2%) in the cervical segment, 6 (7.1%) in the cervical thoracic segment, and 4 (4.7%) in the lumbar segment. MEP recordings were obtained from 81 patients, and the preoperative McCormick score was 1.53 ± 0.69. The sensitivity of multimodal monitoring combined with the criteria of 80% reduction in MEP amplitude and SEP was 83.9%, with a specificity of 69%, a positive predictive value of 69%, and a negative predictive value of 90.4%. This study emphasizes the crucial role of electrophysiological monitoring, particularly MEP and SEP, during the surgical resection of SCMs. The findings demonstrate that this approach is effective in predicting and preventing postoperative neurological dysfunction, thereby improving patient outcomes.

Progress in neurosurgical treatment of neurofibromatosis type 1

To summarize the latest developments in neurosurgical treatments for neurofibromatosis type 1 (NF1) and explore therapeutic strategies to provide comprehensive treatment guidelines for clinicians. The recent domestic and international literature and clinical cases in the field of NF1 were reviewed. The main types of neurological complications associated with NF1 and their treatments were thorough summarized and the future research directions in neurosurgery was analyzed. NF1 frequently results in complex and diverse lesions in the central and peripheral nervous systems, particularly low-grade gliomas in the brain and spinal canal and paraspinal neurofibromas. Treatment decisions should be made by a multidisciplinary team. Symptomatic plexiform neurofibromas and tumors with malignant imaging evidence require neurosurgical intervention. The goals of surgery include reducing tumor size, alleviating pain, and improving appearance. Postoperative functional rehabilitation exercises, long-term multidisciplinary follow-up, and psychosocial interventions are crucial for improving the quality of life for patients. Advanced imaging guidance systems and artificial intelligence technologies can help increase tumor resection rates and reduce recurrence. Neurosurgical intervention is the primary treatment for symptomatic plexiform neurofibromas and malignant peripheral nerve sheath tumors when medical treatment is ineffective and the lesions progress rapidly. Preoperative multidisciplinary assessment, intraoperative electrophysiological monitoring, and advanced surgical assistance devices significantly enhance surgical efficacy and safety. Future research should continue to explore new surgical techniques and improve postoperative management strategies to achieve more precise and personalized treatment for NF1 patients.

Flexible yet Durable Microneedle Electrodes Based on Nanowire-Embedded Polyimide for Precise Wearable Electrophysiological Monitoring.

A precise recording of electrophysiological signals requires high-performance flexible bioelectrodes to build a robust skin interface. The past decade has witnessed encouraging progress in the development of elastomeric electrodes for wearable electrophysiological monitoring; however, it remains challenging to achieve excellent flexibility, conformal contact, and high durability simultaneously. Herein, we report on an effective method to fabricate flexible yet durable microneedle electrodes (MEs) based on vertically aligned gold nanowires (Au NWs) embedded polyimide (PI), which meet the above three design requirements. The Au NWs embedded PI MEs could build conformal contact with human skin and maintain electrical stability with minimal contact impedance by effectively penetrating the stratum corneum of the skin. In comparison studies, we found our MEs outperformed conventional gel or elastomeric soft electrodes. We further integrated the vertical Au-NW MEs into a wearable healthcare system and achieved wireless real-time recordings of electromyography (EMG) and electrocardiography (ECG) with high signal-to-noise ratios (SNRs) and low motion artifacts. Our fabrication strategy opens a new route to improve the durability and reliability of emerging nanomaterial-based soft bioelectrodes for long-term wearable healthcare applications.

Fabric-based lamina emergent MXene-based electrode for electrophysiological monitoring

Commercial wearable biosignal sensing technologies encounter challenges associated with irritation or discomfort caused by unwanted objects in direct contact with the skin, which can discourage the widespread adoption of wearable devices. To address this issue, we propose a fabric-based lamina emergent MXene-based electrode, a lightweight and flexible shape-morphing wearable bioelectrode. This work offers an innovative approach to biosignal sensing by harnessing the high electrical conductivity and low skin-to-electrode contact impedance of MXene-based dry electrodes. Its design, inspired by Nesler’s pneumatic interference actuator, ensures stable skin-to-electrode contact, enabling robust biosignal detection in diverse situations. Extensive research is conducted on key design parameters, such as the width and number of multiple semicircular legs, the radius of the anchoring frame, and pneumatic pressure, to accommodate a wide range of applications. Furthermore, a real-time wireless electrophysiological monitoring system has been developed, with a signal-to-noise ratio and accuracy comparable to those of commercial bioelectrodes. This work excels in recognizing various hand gestures through a convolutional neural network, ultimately introducing a shape-morphing electrode that provides reliable, high-performance biosignal sensing for dynamic users.

Flexible electrodes with enhancement of electronic-ionic conductivity for electrophysiological signal monitoring

Flexible electrodes with enhancement of electronic-ionic conductivity for electrophysiological signal monitoring

Nanoscale Strategies for Enhancing the Performance of Adhesive Dry Electrodes for the Skin.

High-quality electrophysiological monitoring requires electrodes to maintain a compliant and stable skin contact. This necessitates low impedance, good skin compliance, and strong adhesion to ensure continuous and stable contact under dynamic conditions. In this context, adhesive epidermal dry electrodes are advancing rapidly, which is promising for long-term applications in clinical diagnosis, wearable health monitoring, and human-machine interfaces. However, challenges persist, as conventional technologies usually fall short of meeting the high standards required for electrophysiological electrodes. This Perspective discusses four key aspects for high-performance epidermal electrodes from an adhesive perspective: initial adhesion, water resistance, dynamic stability, and removal simplicity. We review recent nanoscale strategies addressing these issues, providing a comprehensive guideline to enhance the application performance of epidermal dry electrodes. Additionally, we explore key nanoscale strategies and their associated functions, future technology roadmaps, and prospects for dry adhesive epidermal electrodes.

Recovery of independent ambulation after complete spinal cord transection in the presence of the neuroprotectant polyethylene glycol in monkeys

ObjectiveDespite the conventional belief that motor function and sensation distal to the site of a complete spinal cord transection are irretrievable, our research has demonstrated significant motor recovery in mice, rats, and dogs by applying polyethylene glycol (PEG) topically via a syringe directly to the contact interface of transected spinal cord. However, before implementing this technology in human subjects, validating PEG's efficacy and enduring impact through experimentation on non-human primates is imperative. MethodsTwo 4-year-old female Macaca fascicularis monkeys underwent complete dorsal cord transection at T10. Postoperative behavioral assessment, electrophysiologic monitoring, and neuroimaging examinations were recorded, and tissues were obtained for histological examination at the end of study. ResultsThe monkey whose spinal cord had been fully transected in the presence of PEG developed useful recovery already at 3 months and near-complete recovery of motor function in the hind-limbs at 18 months. The control animal without PEG remained paralyzed. Cortical somatosensory evoked potentials recovered postoperatively only in PEG-treated monkey vs none in the control. Diffusion tensor imaging showed re-establishment of continuity of the white matter in PEG-treated monkey, but not in the control. Moreover, histology revealed intact neuronal bodies, axons, and myelin tissue at the spinal cord transection site in PEG-treated monkey only. ConclusionThis report suggests that in primates, an acutely transected spinal cord can be re-fused in the presence of PEG with restoration of neural continuity and functional recovery of motor activity distal to the site of transection.

Highly Stretchable and Breathable Dry Bioelectrode with Low Impedance for Electrophysiological Monitoring

Highly Stretchable and Breathable Dry Bioelectrode with Low Impedance for Electrophysiological Monitoring

A retrospective analysis of spinal teratomas and spinal lipomas: overlaps and differences in presentation, surgical treatments, and outcomes

BACKGROUNDSpinal teratomas and lipomas, both adult and pediatric cases, are rare diseases with many similarities, but have yet to be systematically compared. PURPOSETo systematically compare spinal teratomas and lipomas to optimize management. STUDY DESIGNRetrospective. PATIENT SAMPLESymptomatic spinal teratoma and lipoma patients surgically treated at our center. OUTCOME MEASURESAnatomical distribution, clinical manifestations, resection status, and outcomes. METHODSSpinal teratoma and lipoma patients with complete data treated during 2008 to 2023 in our center were enrolled. Electrophysiological monitoring was routinely performed after 2012. Patient characteristics, anatomical distribution, clinical manifestations, surgical resection, and outcomes were analyzed. RESULTSWe enrolled 86 teratoma patients (71 adults) and 51 lipoma patients (39 adults). Most tumors were lumbosacral lesions; cervical/thoracic involvement was more common with lipomas. Pain, the most frequent manifestation, was more common in teratomas. Gross total resection (GTR) was achieved in 51.1% and 49% of teratomas and lipomas, respectively. Electrophysiological monitoring increased the GTR rate from 38.8% to 48.6%. Age independently predicted (OR: 1.040, 95% CI: 1.008–1.078) GTR/near-total resection (NTR). Symptom relief occurred in 81.4% teratoma patients and 64.7% lipoma patients. Recurrence/symptomatic progression occurred in 19 teratomas and 7 lipomas after a median of 95 and 115 months, respectively. Adult lipoma patients without spinal dysraphism had lower recurrence rates. GTR (HR: 0.172, 95% CI: 0.02557–0.7028) and lesion length (HR: 1.351, 95% CI: 1.138–1.607) independently predicted recurrence/progression. CONCLUSIONSGTR should be pursued for adult/pediatric spinal teratomas and pediatric spinal lipomas. For adult spinal lipoma patients without dysraphism, conservative surgery could be considered.

Ultra-stable ionogels based on hydrogen networks with broad temperature, environment, and long-term stability

Ionogels with broad temperature, environment, and long-term stability are desirable in intelligent flexible electronics. Herein, we have developed a novel ultra-stable ionogel through hydrogen bonding between the amphiphilic ionic liquid--1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([EMIM][NTf2]) and butyl acrylate (BA)-ethyl ethoxyethyl acrylate (EO) copolymer (P(BA-co-EO)). The ionogel demonstrates high decomposition voltage, strong adhesion stability, non-corrosive stability, and cyclic strain sensing stability (500 cycles at 120 % strain). Additionally, it exhibits broad temperature and environment adaptability, capable of stretching up to 7 times at −20 °C, maintaining consistent weight after 30 days of storage in extreme environments such as low/high temperatures (−20∼100 °C), high vacuum (6 × 10−4 Pa), and underwater (without additional sealed packaging), while also maintaining electrophysiological monitoring at −20 °C or 100 °C. Most importantly, the ionogel without sealing can self-adhere to the human skin for continuous and high-quality electrophysiological monitoring for 1 month under daily life conditions. We have utilized the ionogel to fabricate an ionic skin with multifunctional sensing capabilities for strain, pressure, and temperature, which has been successfully employed in human motion and pressure detection. It is believed that ionogels with long-term stability will pave the way for developing next-generation intelligent flexible electronics in future research endeavors.

Visual electrophysiologic monitoring of traumatic optic neuropathies requiring neurosurgical interventions.

Visual electrophysiologic monitoring of traumatic optic neuropathies requiring neurosurgical interventions.

Recent Advances of Stretchable Nanomaterial-Based Hydrogels for Wearable Sensors and Electrophysiological Signals Monitoring.

Electrophysiological monitoring is a commonly used medical procedure designed to capture the electrical signals generated by the body and promptly identify any abnormal health conditions. Wearable sensors are of great significance in signal acquisition for electrophysiological monitoring. Traditional electrophysiological monitoring devices are often bulky and have many complex accessories and thus, are only suitable for limited application scenarios. Hydrogels optimized based on nanomaterials are lightweight with excellent stretchable and electrical properties, solving the problem of high-quality signal acquisition for wearable sensors. Therefore, the development of hydrogels based on nanomaterials brings tremendous potential for wearable physiological signal monitoring sensors. This review first introduces the latest advancement of hydrogels made from different nanomaterials, such as nanocarbon materials, nanometal materials, and two-dimensional transition metal compounds, in physiological signal monitoring sensors. Second, the versatile properties of these stretchable composite hydrogel sensors are reviewed. Then, their applications in various electrophysiological signal monitoring, such as electrocardiogram monitoring, electromyographic signal analysis, and electroencephalogram monitoring, are discussed. Finally, the current application status and future development prospects of nanomaterial-optimized hydrogels in wearable physiological signal monitoring sensors are summarized. We hope this review will inspire future development of wearable electrophysiological signal monitoring sensors using nanomaterial-based hydrogels.

Glial expression of Drosophila UBE3A causes spontaneous seizures that can be modulated by 5-HT signaling

Misexpression of the E3 ubiquitin ligase gene UBE3A is thought to contribute to a range of neurological disorders. In the context of Dup15q syndrome, additional genomic copies of UBE3A give rise to the autism, muscle hypotonia and spontaneous seizures characteristics of the disorder. In a Drosophila model of Dup 15q syndrome, it was recently shown that glial-driven expression of the UBE3A ortholog dube3a led to a “bang-sensitive” phenotype, where mechanical shock triggers convulsions, suggesting glial dube3a expression contributes to hyperexcitability in flies. Here we directly compare the consequences of glial- and neuronal-driven dube3a expression on motor coordination and seizure susceptibility in Drosophila.To quantify seizure-related behavioral events, we developed and trained a hidden Markov model that identified these events based on automated video tracking of fly locomotion. Both glial and neuronal driven dube3a expression led to clear motor phenotypes. However, only glial-driven dube3a expression displayed spontaneous seizure-associated immobilization events, that were clearly observed at high-temperature (38 °C). Using a tethered fly preparation amenable to electrophysiological monitoring of seizure activity, we found glial-driven dube3a flies display aberrant spontaneous spike discharges which are bilaterally synchronized. Neither neuronal-dube3a overexpressing flies, nor control flies displayed these firing patterns. We previously performed a drug screen for FDA approved compounds that can suppress bang-sensitivity in glial-driven dube3a expressing flies and identified certain 5-HT modulators as strong seizure suppressors. Here we found glial-driven dube3a flies fed the serotonin reuptake inhibitor vortioxetine and the 5-HT2A antagonist ketanserin displayed reduced immobilization and spike bursting, consistent with the previous study. Together these findings highlight the potential for glial pathophysiology to drive Dup15q syndrome-related seizure activity.

LATEST ADVANCES IN FACIAL NERVE INTRAOPERATIVE MONITORING FOR VESTIBULAR SCHWANNOMA - UP TO DATE 2024

Introduction: Vestibular schwannoma, a benign tumor of the eighth cranial nerve, can be treated with radiosurgery, microsurgery, or observation. This study aims to present advances in intraoperative monitoring techniques for preserving facial nerve function during acoustic neuroma surgeries. By sharing the latest evidence, we hope to influence clinical practices for the benefit of patients. Methodology: Thus, we conducted a comprehensive literature review using the Scopus database, we searched for articles published from 2018 to 2023 using the keywords "facial paralysis," "acoustic neuroma," and "intraoperative monitoring." Results: The use of electromyographic parameters in the pre, intra, and post-resection monitoring of vestibular schwannoma provides valuable indicators of both the functional state of the facial nerve and the tumor adherence. This information plays a crucial role in making safe decisions regarding the extent of tumor resection while minimizing the risk of facial nerve damage during surgery. Supramaximal stimulation of the facial nerve in proximity to the tumor is of utmost importance to preserve facial function. However, the presence of a separate intermediate nerve poses challenges in accurately detecting false positives. Therefore, monitoring the facial nerve during surgery becomes essential to prevent potential injuries and to predict both short- and long-term outcomes. Conclusion: Intraoperative electrophysiological facial nerve monitoring is a crucial strategy to reduce postoperative facial paralysis. While the best technique is still under debate, several options exist to enhance monitoring efficacy and patient safety. By staying informed, clinicians can make better decisions to improve patient outcomes.