Using Optic Nerve Sheath Diameter for Intracranial Pressure (ICP) Monitoring in Traumatic Brain Injury: A Scoping Review.

INTRODUCTION: Neuromonitoring represents a cornerstone in the comprehensive management of patients with traumatic brain injury (TBI), allowing for early detection of complications such as increased intracranial pressure (ICP) [1]. This has led to a search for noninvasive modalities that are reliable and deployable at bedside. Among these, ultrasonographic optic nerve sheath diameter (ONSD) measurement is a strong contender, estimating ICP by quantifying the distension of the optic nerve at higher ICP values. Thus, this scoping review seeks to describe the existing evidence for the use of ONSD in estimating ICP in adult TBI patients as compared to gold-standard invasive methods. MATERIALS AND METHODS: This review was conducted in accordance with the Joanna Briggs Institute methodology for scoping reviews, with a main search of PubMed and EMBASE. The search was limited to studies of adult patients with TBI published in any language between 2012 and 2022. Sixteen studies were included for analysis, with all studies conducted in high-income countries. RESULTS: All of the studies reviewed measured ONSD using the same probe frequency. In most studies, the marker position for ONSD measurement was initially 3 mm behind the globe, retina, or papilla. A few studies utilized additional parameters such as the ONSD/ETD (eyeball transverse diameter) ratio or ODE (optic disc elevation), which also exhibit high sensitivity and reliability. CONCLUSION: Overall, ONSD exhibits great test accuracy and has a strong, almost linear correlation with invasive methods. Thus, ONSD should be considered one of the most effective noninvasive techniques for ICP estimation in TBI patients.

The unexpected paradox of geriatric traumatic brain injury outcomes: Uncovering racial and ethnic disparities.

BACKGROUND: Healthcare disparities have always challenged surgical care in the US. We aimed to assess the influence of disparities on cerebral monitor placement and outcomes of geriatric TBI patients. METHODS: Analysis of 2017-2019 ACS-TQIP. Included severe TBI patients ≥65 years. Patients who died within 24 h were excluded. Outcomes included mortality, cerebral monitors use, complications, and discharge disposition. RESULTS: We included 208,495 patients (White = 175,941; Black = 12,194) (Hispanic = 195,769; Non-Hispanic = 12,258). On multivariable regression, White race was associated with higher mortality (aOR = 1.26; p < 0.001) and SNF/rehab discharge (aOR = 1.11; p < 0.001) and less likely to be discharged home (aOR = 0.90; p < 0.001) or to undergo cerebral monitoring (aOR = 0.77; p < 0.001) compared to Black. Non-Hispanics had higher mortality (aOR = 1.15; p = 0.013), complications (aOR = 1.26; p < 0.001), and SNF/Rehab discharge (aOR = 1.43; p < 0.001) and less likely to be discharged home (aOR = 0.69; p < 0.001) or to undergo cerebral monitoring (aOR = 0.84; p = 0.018) compared to Hispanics. Uninsured Hispanics had the lowest odds of SNF/rehab discharge (aOR = 0.18; p < 0.001). CONCLUSIONS: This study highlights the significant racial and ethnic disparities in the outcomes of geriatric TBI patients. Further studies are needed to address the reason behind these disparities and identify potentially modifiable risk factors in the geriatric trauma population.

A Survey of Neuromonitoring Practices in North American Pediatric Intensive Care Units.

BACKGROUND: Neuromonitoring is the use of continuous measures of brain physiology to detect clinically important events in real-time. Neuromonitoring devices can be invasive or non-invasive and are typically used on patients with acute brain injury or at high risk for brain injury. The goal of this study was to characterize neuromonitoring infrastructure and practices in North American pediatric intensive care units (PICUs). METHODS: An electronic, web-based survey was distributed to 70 North American institutions participating in the Pediatric Neurocritical Care Research Group. Questions related to the clinical use of neuromonitoring devices, integrative multimodality neuromonitoring capabilities, and neuromonitoring infrastructure were included. Survey results were presented using descriptive statistics. RESULTS: The survey was completed by faculty at 74% (52 of 70) of institutions. All 52 institutions measure intracranial pressure and have electroencephalography capability, whereas 87% (45 of 52) use near-infrared spectroscopy and 40% (21/52) use transcranial Doppler. Individual patient monitoring decisions were driven by institutional protocols and collaboration between critical care, neurology, and neurosurgery attendings. Reported device utilization varied by brain injury etiology. Only 15% (eight of 52) of institutions utilized a multimodality neuromonitoring platform to integrate and synchronize data from multiple devices. A database of neuromonitoring patients was maintained at 35% (18 of 52) of institutions. Funding for neuromonitoring programs was variable with contributions from hospitals (19%, 10 of 52), private donations (12%, six of 52), and research funds (12%, six of 52), although 73% (40 of 52) have no dedicated funds. CONCLUSIONS: Neuromonitoring indications, devices, and infrastructure vary by institution in North American pediatric critical care units. Noninvasive modalities were utilized more liberally, although not uniformly, than invasive monitoring. Further studies are needed to standardize the acquisition, interpretation, and reporting of clinical neuromonitoring data, and to determine whether neuromonitoring systems impact neurological outcomes.

Translumbosacral Anorectal Magnetic Stimulation Test for Fecal Incontinence.

BACKGROUND: Neuropathy may cause fecal incontinence and mixed fecal incontinence/constipation, but its prevalence is unclear, partly due to the lack of comprehensive testing of spino-anorectal innervation. OBJECTIVE: This study aimed to develop and determine the clinical usefulness of a novel test, translumbosacral anorectal magnetic stimulation for fecal incontinence. DESIGN: This observational cohort study was conducted from 2012 to 2018. SETTINGS: This study was performed at a tertiary referral center. PATIENTS: Patients with fecal incontinence, patients with mixed fecal incontinence/constipation, and healthy controls were included. INTERVENTIONS: A translumbosacral anorectal magnetic stimulation test was performed by using an anorectal probe with 4 ring electrodes and magnetic coil, and by stimulating bilateral lumbar and sacral plexuses, uses and recording 8 motor-evoked potentials at anal and rectal sites. MAIN OUTCOME MEASURES: The prevalence of lumbar and/or sacral neuropathy was examined. Secondary outcomes were correlation of neuropathy with anorectal sensorimotor function(s) and morphological changes. RESULTS: We evaluated 220 patients: 144 with fecal incontinence, 76 with mixed fecal incontinence/constipation, and 31 healthy controls. All 8 lumbar and sacral motor-evoked potential latencies were significantly prolonged (p < 0.01) in fecal incontinence and mixed fecal incontinence/constipation groups compared with controls. Neuropathy was patchy and involved 4.0 (3.0) (median (interquartile range)) sites. Lumbar neuropathy was seen in 29% to 65% of the patients in the fecal incontinence group and 22% to 61% of the patients in the mixed fecal incontinence/constipation group, and sacral neuropathy was seen in 24% to 64% and 29% to 61% of these patients. Anal neuropathy was significantly more (p < 0.001) prevalent than rectal neuropathy in both groups. There was no correlation between motor-evoked potential latencies and anal sphincter pressures, rectal sensation, or anal sphincter defects. LIMITATIONS: No comparative analysis with electromyography was performed. CONCLUSION: Lumbar or sacral plexus neuropathy was detected in 40% to 75% of patients with fecal incontinence with a 2-fold greater prevalence at the anal region than the rectum. Lumbosacral neuropathy appears to be an independent mechanism in the pathogenesis of fecal incontinence, unassociated with other sensorimotor dysfunctions. Translumbosacral anorectal magnetic stimulation has a high yield and is a safe and clinically useful neurophysiological test. See Video Abstract at http://links.lww.com/DCR/B728. PRUEBA DE ESTIMULACIN MAGNTICA TRANSLUMBOSACRAL ANORECTAL PARA LA INCONTINENCIA FECAL: ANTECEDENTES:La neuropatía puede causar incontinencia fecal y una combinación de incontinencia fe-cal/estreñimiento, pero su prevalencia no está clara, en parte debido a la falta de pruebas comple-tas de inervación espino-anorrectal.OBJETIVO:Desarrollar y determinar la utilidad clínica de una nueva prueba, estimulación magnética trans-lumbosacral anorrectal para la incontinencia fecal.DISEÑO:Estudio de cohorte observacional del 2012 al 2018.ENTORNO CLINICO:Centro de referencia terciario.PACIENTES:Pacientes con incontinencia fecal, combinación de incontinencia fecal/estreñimiento y controles sanos.INTERVENCIONES:Se realizó una prueba de estimulación magnética translumbosacral anorrectal utilizando una sonda anorrectal con 4 electrodos anulares y bobina magnética, y estimulando los plexos lumbares y sacros bilaterales y registrando ocho potenciales evocados motores las regiones anal y rectal.PRINCIPALES MEDIDAS DE RESULTADO:Se examinó la prevalencia de neuropatía lumbar y/o sacra. Los resultados secundarios fueron la correlación de la neuropatía con las funciones sensitivomotoras anorrectales y cambios morfológi-cos.RESULTADOS:Evaluamos 220 pacientes, 144 con incontinencia fecal, 76 con combinación de incontinencia fe-cal/estreñimiento y 31 sujetos sanos. Las ocho latencias de los potenciales evocadas motoras lum-bares y sacras se prolongaron significativamente (p <0,01) en la incontinencia fecal y el grupo mixto en comparación con los controles. La neuropatía fue irregular y afectaba 4,0 (3,0) (mediana (rango intercuartílico) sitios. Se observó neuropatía lumbar en 29-65% en la incontinencia fecal y 22-61% en el grupo mixto, y neuropatía sacra en 24-64% y 29-61 % de pacientes respectivamen-te. La neuropatía anal fue significativamente más prevalente (p <0,001) que la rectal en ambos grupos. No hubo correlación entre las latencias de los potenciales evocadas motoras y las presio-nes del esfínter anal, la sensación rectal o los defectos del esfínter anal.LIMITACIONES:Sin análisis comparativo con electromiografía.CONCLUSIÓNES:Se detectó neuropatía del plexo lumbar o sacro en el 40-75% de los pacientes con incontinencia fecal con una prevalencia dos veces mayor en la región anal que en el recto. La neuropatía lumbo-sacra parece ser un mecanismo independiente en la patogenia de la incontinencia fecal, no asocia-do con otras disfunciones sensitivomotoras. La estimulación magnética translumbosacral anorrec-tal tiene un alto rendimiento, es una prueba neurofisiológica segura y clínicamente útil. Consulte Video Resumen en http://links.lww.com/DCR/B728.

Microdialysis and microperfusion electrodes in neurologic disease monitoring.

Contemporary biomarker collection techniques in blood and cerebrospinal fluid have to date offered only modest clinical insights into neurologic diseases such as epilepsy and glioma. Conversely, the collection of human electroencephalography (EEG) data has long been the standard of care in these patients, enabling individualized insights for therapy and revealing fundamental principles of human neurophysiology. Increasing interest exists in simultaneously measuring neurochemical biomarkers and electrophysiological data to enhance our understanding of human disease mechanisms. This review compares microdialysis, microperfusion, and implanted EEG probe architectures and performance parameters. Invasive consequences of probe implantation are also investigated along with the functional impact of biofouling. Finally, previously developed microdialysis electrodes and microperfusion electrodes are reviewed in preclinical and clinical settings. Critically, current and precedent microdialysis and microperfusion probes lack the ability to collect neurochemical data that is spatially and temporally coincident with EEG data derived from depth electrodes. This ultimately limits diagnostic and therapeutic progress in epilepsy and glioma research. However, this gap also provides a unique opportunity to create a dual-sensing technology that will provide unprecedented insights into the pathogenic mechanisms of human neurologic disease.

Real time monitoring of dopamine release evoked by mitragynine (Kratom): An insight through electrochemical sensor.

BACKGROUND: Mitragynine, the major indole alkaloid from Mitragyna speciosa has been reported previously to possess abuse liability. However, there are insufficient data suggesting the mechanism through which this pharmacological agent causes addiction. AIMS: In this study, we investigated the effects of mitragynine on dopamine (DA) level and dopamine transporter (DAT) expression from the rat's frontal cortex. METHODS: DA level was recorded in the brain samples of animals treated with acute or repeated exposure for 4 consecutive days with either vehicle or mitragynine (1 and 30 mg/kg) using electrochemical sensor. Animals were then decapitated and the brain regions were removed, snap-frozen in liquid nitrogen and immediately stored at -80 °C. DA level was quantified using Enzyme linked immunosorbent assay (ELISA) kits and DAT gene expression was determined using quantitative real time polymerase chain reaction (RT-qPCR). RESULTS/OUTCOME: Mitragynine (1 and 30 mg/kg) did not increase DA release following acute treatment, however, after repeated exposure at day 4, mitragynine significantly and dose dependently increased DA release in the frontal cortex. In this study, we also observed a significant increase in DAT mRNA expression at day 4 in group treated with mitragynine (30 mg/kg). CONCLUSION/INTERPRETATION: Data from this study indicates that mitragynine significantly increased DA release when administered repeatedly, increased in DAT mRNA expression with the highest tested dose (30 mg/kg). Therefore, the rewarding effects observed after mitragynine administration could be due to its ability to increase DA content in certain areas of the brain especially the frontal cortex.

Changes in electroencephalographic power and bicoherence spectra according to depth of dexmedetomidine sedation in patients undergoing spinal anesthesia.

Background: Assessment the depth of dexmedetomidine sedation using electroencephalographic (EEG) features can improve the quality of procedural sedation. Previous volunteer studies of dexmedetomidine-induced EEG changes need to be validated, and changes in bicoherence spectra during dexmedetomidine sedation has not been revealed yet. We aimed to investigate the dexmedetomidine-induced EEG change using power spectral and bicoherence analyses in the clinical setting. Patients and Methods: Thirty-six patients undergoing orthopedic surgery under spinal anesthesia were enrolled in this study. Dexmedetomidine sedation was conducted by the stepwise increase in target effect site concentration (Ce) while assessing sedation levels. Bispectral index (BIS) and frontal electroencephalography were recorded continuously, and the performance of BIS and changes in power and bicoherence spectra were analyzed with the data from the F3 electrode. Results: The prediction probability values for detecting different sedation levels were 0.847, 0.841, and 0.844 in BIS, 95% spectral edge frequency, and dexmedetomidine Ce, respectively. As the depth of sedation increased, δ power increased, but high ß and γ power decreased significantly (P <0.001). α and spindle power increased significantly under light and moderate sedation (P <0.001 in light vs baseline and deep sedation; P = 0.002 and P <0.001 in moderate sedation vs baseline and deep sedation, respectively). The bicoherence peaks of the δ and α-spindle regions along the diagonal line of the bicoherence matrix emerged during moderate and deep sedation. Peak bicoherence in the δ area showed sedation-dependent increases (29.93%±7.38%, 36.72%±9.70%, 44.88%±12.90%; light, moderate, and deep sedation; P = 0.008 and P <0.001 in light sedation vs moderate and deep sedation, respectively; P = 0.007 in moderate sedation vs deep sedation), whereas peak bicoherence in the α-spindle area did not change (22.92%±4.90%, 24.72%±4.96%, and 26.96%±8.42%, respectively; P=0.053). Conclusions: The increase of δ power and the decrease of high-frequency power were associated with the gradual deepening of dexmedetomidine sedation. The δ bicoherence peak increased with increasing sedation level and can serve as an indicator reflecting dexmedetomidine sedation levels.

Automated seizure detection using wearable devices: A clinical practice guideline of the International League Against Epilepsy and the International Federation of Clinical Neurophysiology.

The objective of this clinical practice guideline (CPG) is to provide recommendations for healthcare personnel working with patients with epilepsy, on the use of wearable devices for automated seizure detection in patients with epilepsy, in outpatient, ambulatory settings. The Working Group of the International League Against Epilepsy and the International Federation of Clinical Neurophysiology developed the CPG according to the methodology proposed by the ILAE Epilepsy Guidelines Working Group. We reviewed the published evidence using The Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement and evaluated the evidence and formulated the recommendations following the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. We found high level of evidence for the accuracy of automated detection of generalized tonic-clonic seizures (GTCS) and focal-to-bilateral tonic-clonic seizures (FBTCS) and recommend use of wearable automated seizure detection devices for selected patients when accurate detection of GTCS and FBTCS is recommended as a clinical adjunct. We also found moderate level of evidence for seizure types without GTCs or FBTCs. However, it was uncertain whether the detected alarms resulted in meaningful clinical outcomes for the patients. We recommend using clinically validated devices for automated detection of GTCS and FBTCS, especially in unsupervised patients, where alarms can result in rapid intervention (weak/conditional recommendation). At present, we do not recommend clinical use of the currently available devices for other seizure types (weak/conditional recommendation). Further research and development are needed to improve the performance of automated seizure detection and to document their accuracy and clinical utility.

Portable Neuromonitoring Device Detects Large Vessel Occlusion in Suspected Acute Ischemic Stroke.

BACKGROUND AND PURPOSE: Early detection of large vessel occlusion (LVO) stroke optimizes endovascular therapy and improves outcomes. Clinical stroke severity scales used for LVO identification have variable accuracy. We investigated a portable LVO-detection device (PLD), using electroencephalography and somatosensory-evoked potentials, to identify LVO stroke. METHODS: We obtained PLD data in suspected patients with stroke enrolled prospectively via a convenience sample in 8 emergency departments within 24 hours of symptom onset. LVO discriminative signals were integrated into a binary classifier. The National Institutes of Health Stroke Scale was documented, and 4 prehospital stroke scales were retrospectively calculated. We compared PLD and scale performance to diagnostic neuroimaging. RESULTS: Of 109 patients, there were 25 LVO (23%), 38 non-LVO ischemic (35%), 14 hemorrhages (13%), and 32 stroke mimics (29%). The PLD had higher sensitivity (80% [95% CI, 74-85]) and similar specificity (80% [95% CI, 77-83]) to all prehospital scales at their predetermined high probability LVO thresholds. The PLD had high discrimination for LVO (C-statistic=0.88). CONCLUSIONS: The PLD identifies LVO with superior accuracy compared with prehospital stroke scales in emergency department suspected stroke. Future studies need to validate the PLD's potential as an LVO triage aid in prehospital undifferentiated stroke populations.

Telemetric monitoring in idiopathic intracranial hypertension demonstrates intracranial pressure in a case with sight-threatening disease.

The understanding of raised intracranial pressure (ICP) is increasing with the directed use of intracranial telemetric ICP monitors. This case uniquely observed ICP changes by telemetric monitoring in a patient with idiopathic intracranial hypertension (IIH), who developed rapid sight-threatening disease. A lumbar drain was inserted, as a temporising measure, and was clamped prior to surgery. This resulted in a rapid rise in ICP, which normalised after insertion of a ventriculoperitoneal shunt. This case highlighted the utility of the ICP monitor and the lumbar drain as a temporising measure to control ICP prior to a definitive procedure as recommended by the IIH consensus guidelines.

A wireless, skin-interfaced biosensor for cerebral hemodynamic monitoring in pediatric care.

The standard of clinical care in many pediatric and neonatal neurocritical care units involves continuous monitoring of cerebral hemodynamics using hard-wired devices that physically adhere to the skin and connect to base stations that commonly mount on an adjacent wall or stand. Risks of iatrogenic skin injuries associated with adhesives that bond such systems to the skin and entanglements of the patients and/or the healthcare professionals with the wires can impede clinical procedures and natural movements that are critical to the care, development, and recovery of pediatric patients. This paper presents a wireless, miniaturized, and mechanically soft, flexible device that supports measurements quantitatively comparable to existing clinical standards. The system features a multiphotodiode array and pair of light-emitting diodes for simultaneous monitoring of systemic and cerebral hemodynamics, with ability to measure cerebral oxygenation, heart rate, peripheral oxygenation, and potentially cerebral pulse pressure and vascular tone, through the utilization of multiwavelength reflectance-mode photoplethysmography and functional near-infrared spectroscopy. Monte Carlo optical simulations define the tissue-probing depths for source-detector distances and operating wavelengths of these systems using magnetic resonance images of the head of a representative pediatric patient to define the relevant geometries. Clinical studies on pediatric subjects with and without congenital central hypoventilation syndrome validate the feasibility for using this system in operating hospitals and define its advantages relative to established technologies. This platform has the potential to substantially enhance the quality of pediatric care across a wide range of conditions and use scenarios, not only in advanced hospital settings but also in clinics of lower- and middle-income countries.

Comparative investigation of different telemetric methods for measuring intracranial pressure: a prospective pilot study.

OBJECTIVES: Measurement of intracranial pressure (ICP) plays an important role in long-term monitoring and neuro-intensive treatment of patients with a cerebral shunt. Currently, only two complete telemetric implants with different technical features are available worldwide. This prospective pilot study aims to examine patients who had both probes implanted at overlapping times for clinical reasons and represents the first in vivo comparison of both measurement methods. MATERIALS AND METHODS: Patients with a primary subarachnoid hemorrhage or a spontaneous intracerebral hemorrhage with ventricular hemorrhage who had received a telemetric ICP probe (Raumedic® NEUROVENT®-P-tel) were included in the study. Conventional external ventricular drainages (EVD) and ventriculoperitoneal shunts with a telemetric ICP probe (Miethke Sensor Reservoir) were implanted in patients with hydrocephalus who required CSF (cerebrospinal fluid) drainage. Absolute ICP values from all systems were obtained. Due to the overlapping implantation time, parallel ICP measurements were performed via two devices simultaneously. ICP measurements via the sensor reservoir were repeated after 3 and 9 months. Differences between the absolute ICP values measured via the NEUROVENT®-P-tel probe, the Miethke sensor reservoir®, and the EVD were analyzed. RESULTS: Seventeen patients were included in the present study between 2016 and 2018. 63% of all patients were male. In 11 patients the ICP measurements were followed up with both devices for 3 months. ICP measurements of the sensor reservoir showed corresponding trends in 9 cases compared to ICP measurement via the telemetry probe or EVD. Difference in absolute ICP values ranged between 14.5 mmHg and 0.0 mmHg. The average difference of the absolute ICP values in 8 cases was ≤ 3.5 mmHg. CONCLUSION: ICP measurements with both systems continuously showed synchronous absolute ICP values, however absolute values of ICP measurement with the different systems did not match.

Traumatic brain injury neuroelectrochemical monitoring: behind-the-ear micro-instrument and cloud application.

BACKGROUND: Traumatic Brain Injury (TBI) is a leading cause of fatality and disability worldwide, partly due to the occurrence of secondary injury and late interventions. Correct diagnosis and timely monitoring ensure effective medical intervention aimed at improving clinical outcome. However, due to the limitations in size and cost of current ambulatory bioinstruments, they cannot be used to monitor patients who may still be at risk of secondary injury outside the ICU. METHODS: We propose a complete system consisting of a wearable wireless bioinstrument and a cloud-based application for real-time TBI monitoring. The bioinstrument can simultaneously record up to ten channels including both ECoG biopotential and neurochemicals (e.g. potassium, glucose and lactate), and supports various electrochemical methods including potentiometry, amperometry and cyclic voltammetry. All channels support variable gain programming to automatically tune the input dynamic range and address biosensors' falling sensitivity. The instrument is flexible and can be folded to occupy a small space behind the ear. A Bluetooth Low-Energy (BLE) receiver is used to wirelessly connect the instrument to a cloud application where the recorded data is stored, processed and visualised in real-time. Bench testing has been used to validate device performance. RESULTS: The instrument successfully monitored spreading depolarisations (SDs) - reproduced using a signal generator - with an SNR of 29.07 dB and NF of 0.26 dB. The potentiostat generates a wide voltage range from -1.65V to +1.65V with a resolution of 0.8mV and the sensitivity of the amperometric AFE was verified by recording 5 pA currents. Different potassium, glucose and lactate concentrations prepared in lab were accurately measured and their respective working curves were constructed. Finally,the instrument achieved a maximum sampling rate of 1.25 ksps/channel with a throughput of 105 kbps. All measurements were successfully received at the cloud. CONCLUSION: The proposed instrument uniquely positions itself by presenting an aggressive optimisation of size and cost while maintaining high measurement accuracy. The system can effectively extend neuroelectrochemical monitoring to all TBI patients including those who are mobile and those who are outside the ICU. Finally, data recorded in the cloud application could be used to help diagnosis and guide rehabilitation.

Continuous Optical Monitoring of Spinal Cord Oxygenation and Hemodynamics during the First Seven Days Post-Injury in a Porcine Model of Acute Spinal Cord Injury.

One of the only currently available treatment options to potentially improve neurological recovery after acute spinal cord injury (SCI) is augmentation of mean arterial blood pressure (MAP) to promote blood flow and oxygen delivery to the injured cord. However, to optimize such hemodynamic management, clinicians require a method to monitor the physiological effects of these MAP alterations within the injured cord. Therefore, we investigated the feasibility and effectiveness of using a novel optical sensor, based on near-infrared spectroscopy (NIRS), to monitor real-time spinal cord oxygenation and hemodynamics during the first 7 days post-injury in a porcine model of acute SCI. Six Yucatan miniature pigs underwent a T10 vertebral level contusion-compression injury. Spinal cord oxygenation and hemodynamics were continuously monitored by a minimally invasive custom-made NIRS sensor, and by invasive intraparenchymal (IP) probes to validate the NIRS measures. Episodes of MAP alteration and hypoxia were performed acutely after injury, and at 2 and 7 days post-injury to simulate the types of hemodynamic changes SCI patients experience after injury. The NIRS sensor demonstrated the ability to provide oxygenation and hemodynamic measurements over the 7-day post-SCI period. NIRS measures showed statistically significant correlations with each of the invasive IP measures and MAP changes during episodes of MAP alteration and hypoxia throughout the first week post-injury (p < 0.05). These results indicate that this novel NIRS system can monitor real-time changes in spinal cord oxygenation and hemodynamics over the first 7 days post-injury, and has the ability to detect local tissue changes that are reflective of systemic hemodynamic changes.

Long-term monitoring of intracranial pressure in freely-moving rats; impact of different physiological states.

BACKGROUND: Elevated intracranial pressure (ICP) is observed in association with a range of brain disorders. There is limited insight into the regulatory mechanisms of ICP under physiological conditions, and consequently also under pathological conditions. Thereby, to understand the mechanisms underlying ICP dynamics, precise, valid and long-term ICP recordings are of importance in the preclinical setting. Herein, we used a novel telemetric system for ICP recordings which allowed for long-term recordings in freely-moving rats. The aim was to investigate ICP dynamics under different physiological states and investigate how factors such as surgery/recovery, body position, light-dark, co-housing, weight and anesthesia may influence ICP and its waveforms. METHODS: A telemetric device was implanted epidurally in rats and signals were recorded continuously for up to 50 days (n = 14). Recording was divided into three experimental periods: a surgical recovery period (RP), a physiological period (PP) and an experimental period (EP). Histology was performed to study the morphology of implanted rats and non-implanted rats (n = 17). RESULTS: For the first time, we can demonstrate continuous ICP recordings in freely-moving and co-housed rats for up to 50 days with a high degree of stability. The mean ICP in the recording periods were; RP: 3.2 ± 0.6 mmHg, PP: 5.0 ± 0.6 mmHg and EP: 4.7 ± 0.6 mmHg. In the RP, the ICP was significantly lower compared to the PP (P = 0.0034). Significant light-dark difference in ICP with 21% increase in respiratory slow-wave amplitude was observed in the co-housed animals but not in single-housed animals. The ICP signal was raised during the dark period relative to the light (Δ0.3 ± 0.07 mmHg, P = 0.0043). Administration of anesthesia gave a short-term increase in ICP followed by a significant decrease in ICP. No signs of tissue damage or inflammation were found in the implanted brains. CONCLUSIONS: ICP dynamics were influenced by several factors such as, use of anesthesia, light-dark difference and housing conditions. Our study demonstrates the importance of performing ICP physiological measurements in freely-moving animals. This has significant implications for moving the preclinical research field forward in order to properly study ICP physiology during disease development and to explore drug targets for alleviating increased ICP.

Measuring intracranial pressure by invasive, less invasive or non-invasive means: limitations and avenues for improvement.

Sixty years have passed since neurosurgeon Nils Lundberg presented his thesis about intracranial pressure (ICP) monitoring, which represents a milestone for its clinical introduction. Monitoring of ICP has since become a clinical routine worldwide, and today represents a cornerstone in surveillance of patients with acute brain injury or disease, and a diagnostic of individuals with chronic neurological disease. There is, however, controversy regarding indications, clinical usefulness and the clinical role of the various ICP scores. In this paper, we critically review limitations and weaknesses with the current ICP measurement approaches for invasive, less invasive and non-invasive ICP monitoring. While risk related to the invasiveness of ICP monitoring is extensively covered in the literature, we highlight other limitations in current ICP measurement technologies, including limited ICP source signal quality control, shifts and drifts in zero pressure reference level, affecting mean ICP scores and mean ICP-derived indices. Control of the quality of the ICP source signal is particularly important for non-invasive and less invasive ICP measurements. We conclude that we need more focus on mitigation of the current limitations of today's ICP modalities if we are to improve the clinical utility of ICP monitoring.

Stereoelectroencephalography Versus Subdural Strip Electrode Implantations: Feasibility, Complications, and Outcomes in 500 Intracranial Monitoring Cases for Drug-Resistant Epilepsy.

BACKGROUND: Both stereoelectroencephalography (SEEG) and subdural strip electrodes (SSE) are used for intracranial electroencephalographic recordings in the invasive investigation of patients with drug-resistant epilepsy. OBJECTIVE: To compare SEEG and SSE with respect to feasibility, complications, and outcome in this single-center study. METHODS: Patient characteristics, periprocedural parameters, complications, and outcome were acquired from a pro- and retrospectively managed databank to compare SEEG and SSE cases. RESULTS: A total of 500 intracranial electroencephalographic monitoring cases in 450 patients were analyzed (145 SEEG and 355 SSE). Both groups were of similar age, gender distribution, and duration of epilepsy. Implantation of each SEEG electrode took 13.9 ± 7.6 min (20 ± 12 min for each SSE; P < .01). Radiation exposure to the patient was 4.3 ± 7.7 s to a dose area product of 14.6 ± 27.9 rad*cm2 for SEEG and 9.4 ± 8.9 s with 21 ± 22.4 rad*cm2 for SSE (P < .01). There was no difference in the length of stay (12.2 ± 7.2 and 12 ± 6.3 d). The complication rate was low in both groups. No infections were seen in SEEG cases (2.3% after SSE). The rate of hemorrhage was 2.8% for SEEG and 1.4% for SSE. Surgical outcome was similar. CONCLUSION: SEEG allows targeting deeply situated foci with a non-inferior safety profile to SSE and seizure outcome comparable to SSE.

Seizure detection at home: Do devices on the market match the needs of people living with epilepsy and their caregivers?

In patients with epilepsy, the potential to prevent seizure-related injuries and to improve the unreliability of seizure self-report have fostered the development and marketing of numerous seizure detection devices for home use. Understanding the requirements of users (patients and caregivers) is essential to improve adherence and mitigate barriers to the long-term use of such devices. Here we reviewed the evidence on the needs and preferences of users and provided an overview of currently marketed devices for seizure detection (medically approved or with published evidence for their performance). We then compared devices with known needs. Seizure-detection devices are expected to improve safety and clinical and self-management, and to provide reassurance to users. Key factors affecting a device's usability relate to its design (attractive appearance, low visibility, low intrusiveness), comfort of use, confidentiality of recorded data, and timely support from both technical and clinical ends. High detection sensitivity and low false alarm rates are paramount. Currently marketed devices are focused primarily on the recording of non-electroencephalography (EEG) signals associated with tonic-clonic seizures, whereas the detection of focal seizures without major motor features remains a clear evidence gap. Moreover, there is paucity of evidence coming from real-life settings. A joint effort of clinical and nonclinical experts, patients, and caregivers is required to ensure an optimal level of acceptability and usability, which are key aspects for a successful continuous monitoring aimed at seizure detection at home.

Application of Robot-Assisted Frameless Stereoelectroencephalography Based on Multimodal Image Guidance in Pediatric Refractory Epilepsy: Experience of a Pediatric Center in a Developing Country.

OBJECTIVE: To introduce the application of robot-assisted frameless stereoelectroencephalography (SEEG) based on multimodal image fusion technology in pediatric refractory epilepsy in a pediatric center from a developing country. METHODS: We retrospectively evaluated pediatric patients with drug-resistant epilepsy who underwent SEEG monitoring at the Children's Hospital of Fudan University from July 2014 to August 2017. Application of multimodal image fusion technology in SEEG was described in detail. Seizure outcomes were assessed according to the International League Against Epilepsy classification. RESULTS: A total of 208 patients were initially eligible and underwent a rigorous phase I evaluation. SEEG explorations were performed in 20 patients who entered phase II assessment (11 male and 9 female patients) with a median age of 7.99 ± 4.07 years. In total, 181 electrodes were implanted (9 per implantation), among which 16 implantations were unilateral (6 left and 10 right) and 4 were bilateral. The mean operating time was 3 hours and no obvious hemorrhage occurred. Electrode displacement and pneumocephalus were observed in 1 and 2 patients, respectively. Thirteen and 7 patients underwent tailored resection and radiofrequency thermocoagulation, respectively. Among resection cases, focal cortical dysplasia was the predominant pathologic type. The overall seizure outcome after a mean follow-up of 2.65 years was International League Against Epilepsy class 1 in 13, class 2 in 2, class 3 in 3, class 4 in 1, and class 5 in 1 patient, respectively. CONCLUSIONS: The combination of multimodal image fusion and frameless robot-assisted SEEG is demonstrated to be safe and effective on children with refractory epilepsy in developing countries.

Current status of pediatric neurocritical care in Argentina. / Estado actual del soporte neurológico crítico en pediatría en la Argentina.

INTRODUCTION: Patients with neurocritical injuries account for 10-16 % of pediatric intensive care unit (PICU) admissions and frequently require neuromonitoring. OBJECTIVE: To describe the current status of neuromonitoring in Argentina. METHODS: Survey with 37 questions about neuromonitoring without including patients' data. Period: April-June 2017. RESULTS: Thirty-eight responses were received out of 71 requests (14 districts with 11 498 annual discharges). The PICU/hospital bed ratio was 21.9 (range: 4.2-66.7). Seventy-four percent of PICUs were public; 61 %, university-affiliated; and 71 %, level I. The availability of monitoring techniques was similar between public and private (percentages): intracranial pressure (95), electroencephalography (92), transcranial Doppler (53), evoked potentials (50), jugular saturation (47), and bispectral index (11). Trauma was the main reason for monitoring. CONCLUSION: Except for intracranial pressure and electroencephalography, neuromonitoring resources are scarce and active neurosurgery availability is minimal. A PICU national registry is required.

Introducción. Los pacientes con lesiones neurocríticas representan el 10-16 % de los ingresos a unidades de cuidados intensivos pediátricas (UCIP) y, frecuentemente, requieren neuromonitoreo. Objetivo. Describir el estado actual del neuromonitoreo en la Argentina. Métodos. Encuesta con 37 preguntas sobre neuromonitoreo sin incluir datos de pacientes. Período: abril-junio, 2017. Resultados. Se recibieron 38 respuestas a 71 solicitudes (14 distritos con 11 498 egresos anuales). La relación camas de UCIP/hospitalarias fue 21,9 (rango: 4,2-66,7). El 74 % fueron públicas; el 61 %, universitarias, y el 71 %, nivel 1. La disponibilidad fue similar entre públicas y privadas (porcentajes): presión intracraneana (95), electroencefalografía (92), doppler transcraneano (53), potenciales evocados (50), saturación yugular (47) e índice bispectral (11). El principal motivo de monitoreo fue trauma. Conclusión. Excepto la presión intracraneana y la electroencefalografía, los recursos de neuromonitoreo son escasos y la disponibilidad de neurocirugía activa es mínima. Se necesita un registro nacional de UCIP.