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Alkhachroum A, Appavu B, Egawa S, Foreman B, Gaspard N, Gilmore EJ, Hirsch LJ, Kurtz P, Lambrecq V, Kromm J, Vespa P, Zafar SF, Rohaut B, Claassen J. Electroencephalogram in the intensive care unit: a focused look at acute brain injury. Intensive Care Med 2022; 48:1443-1462. [PMID: 35997792 PMCID: PMC10008537 DOI: 10.1007/s00134-022-06854-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 07/31/2022] [Indexed: 02/04/2023]
Abstract
Over the past decades, electroencephalography (EEG) has become a widely applied and highly sophisticated brain monitoring tool in a variety of intensive care unit (ICU) settings. The most common indication for EEG monitoring currently is the management of refractory status epilepticus. In addition, a number of studies have associated frequent seizures, including nonconvulsive status epilepticus (NCSE), with worsening secondary brain injury and with worse outcomes. With the widespread utilization of EEG (spot and continuous EEG), rhythmic and periodic patterns that do not fulfill strict seizure criteria have been identified, epidemiologically quantified, and linked to pathophysiological events across a wide spectrum of critical and acute illnesses, including acute brain injury. Increasingly, EEG is not just qualitatively described, but also quantitatively analyzed together with other modalities to generate innovative measurements with possible clinical relevance. In this review, we discuss the current knowledge and emerging applications of EEG in the ICU, including seizure detection, ischemia monitoring, detection of cortical spreading depolarizations, assessment of consciousness and prognostication. We also review some technical aspects and challenges of using EEG in the ICU including the logistics of setting up ICU EEG monitoring in resource-limited settings.
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Affiliation(s)
- Ayham Alkhachroum
- Department of Neurology, University of Miami, Miami, FL, USA
- Department of Neurology, Jackson Memorial Hospital, Miami, FL, USA
| | - Brian Appavu
- Department of Child Health and Neurology, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, USA
- Department of Neurosciences, Phoenix Children's Hospital, Phoenix, AZ, USA
| | - Satoshi Egawa
- Neurointensive Care Unit, Department of Neurosurgery, and Stroke and Epilepsy Center, TMG Asaka Medical Center, Saitama, Japan
| | - Brandon Foreman
- Department of Neurology and Rehabilitation Medicine, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH, USA
| | - Nicolas Gaspard
- Department of Neurology, Erasme Hospital, Free University of Brussels, Brussels, Belgium
| | - Emily J Gilmore
- Comprehensive Epilepsy Center, Department of Neurology, Yale University School of Medicine, New Haven, CT, USA
- Neurocritical Care and Emergency Neurology, Department of Neurology, Ale University School of Medicine, New Haven, CT, USA
| | - Lawrence J Hirsch
- Comprehensive Epilepsy Center, Department of Neurology, Yale University School of Medicine, New Haven, CT, USA
| | - Pedro Kurtz
- Department of Intensive Care Medicine, D'or Institute for Research and Education, Rio de Janeiro, Brazil
- Neurointensive Care, Paulo Niemeyer State Brain Institute, Rio de Janeiro, Brazil
| | - Virginie Lambrecq
- Department of Clinical Neurophysiology and Epilepsy Unit, AP-HP, Pitié Salpêtrière Hospital, Reference Center for Rare Epilepsies, 75013, Paris, France
| | - Julie Kromm
- Departments of Critical Care Medicine and Clinical Neurosciences, Cumming School of Medicine, Calgary, AB, Canada
- Hotchkiss Brain Institute, Cumming School of Medicine, Calgary, AB, Canada
| | - Paul Vespa
- Brain Injury Research Center, Department of Neurosurgery, University of California, Los Angeles, USA
| | - Sahar F Zafar
- Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
| | - Benjamin Rohaut
- Department of Neurology, Sorbonne Université, Pitié-Salpêtrière-AP-HP and Paris Brain Institute, ICM, Inserm, CNRS, Paris, France
| | - Jan Claassen
- Department of Neurology, Neurological Institute, Columbia University, New York Presbyterian Hospital, 177 Fort Washington Avenue, MHB 8 Center, Room 300, New York, NY, 10032, USA.
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Balu R, Foreman B. Introduction to Spreading Depolarizations Special Edition Volume 2. Neurocrit Care 2022; 37:1-2. [PMID: 35763259 DOI: 10.1007/s12028-022-01554-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Ramani Balu
- Neurocritical Care Division, Inova Fairfax Hospital, Falls Church, VA, USA.
| | - Brandon Foreman
- Neurocritical Care Division, University of Cincinnati, Cincinnati, OH, USA
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Gugger JJ, Diaz-Arrastia R. The Frontier of Electrophysiologic Monitoring in Acute Brain Injury. Neurocrit Care 2022; 37:3-4. [PMID: 35488170 DOI: 10.1007/s12028-022-01500-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 03/28/2022] [Indexed: 02/04/2023]
Affiliation(s)
- James J Gugger
- Department of Neurology, University of Pennsylvania Perelman School of Medicine Penn Presbyterian Medical Center, Andrew Mutch Bldg., Room 409 51 North 39th St.,, Philadelphia, PA, 19104, USA
| | - Ramon Diaz-Arrastia
- Department of Neurology, University of Pennsylvania Perelman School of Medicine Penn Presbyterian Medical Center, Andrew Mutch Bldg., Room 409 51 North 39th St.,, Philadelphia, PA, 19104, USA.
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Numerical Simulation of Concussive-Generated Cortical Spreading Depolarization to Optimize DC-EEG Electrode Spacing for Noninvasive Visual Detection. Neurocrit Care 2022; 37:67-82. [PMID: 35233716 DOI: 10.1007/s12028-021-01430-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 12/29/2021] [Indexed: 12/30/2022]
Abstract
BACKGROUND Cortical spreading depolarization (SD) is a propagating depolarization wave of neurons and glial cells in the cerebral gray matter. SD occurs in all forms of severe acute brain injury, as documented by using invasive detection methods. Based on many experimental studies of mechanical brain deformation and concussion, the occurrence of SDs in human concussion has often been hypothesized. However, this hypothesis cannot be confirmed in humans, as SDs can only be detected with invasive detection methods that would require either a craniotomy or a burr hole to be performed on athletes. Typical electroencephalography electrodes, placed on the scalp, can help detect the possible presence of SD but have not been able to accurately and reliably identify SDs. METHODS To explore the possibility of a noninvasive method to resolve this hurdle, we developed a finite element numerical model that simulates scalp voltage changes that are induced by a brain surface SD. We then compared our simulation results with retrospectively evaluated data in patients with aneurysmal subarachnoid hemorrhage from Drenckhahn et al. (Brain 135:853, 2012). RESULTS The ratio of peak scalp to simulated peak cortical voltage, Vscalp/Vcortex, was 0.0735, whereas the ratio from the retrospectively evaluated data was 0.0316 (0.0221, 0.0527) (median [1st quartile, 3rd quartile], n = 161, p < 0.001, one sample Wilcoxon signed-rank test). These differing values provide validation because their differences can be attributed to differences in shape between concussive SDs and aneurysmal subarachnoid hemorrhage SDs, as well as the inherent limitations in human study voltage measurements. This simulated scalp surface potential was used to design a virtual scalp detection array. Error analysis and visual reconstruction showed that 1 cm is the optimal electrode spacing to visually identify the propagating scalp voltage from a cortical SD. Electrode spacings of 2 cm and above produce distorted images and high errors in the reconstructed image. CONCLUSIONS Our analysis suggests that concussive (and other) SDs can be detected from the scalp, which could confirm SD occurrence in human concussion, provide concussion diagnosis on the basis of an underlying physiological mechanism, and lead to noninvasive SD detection in the setting of severe acute brain injury.
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Hartings JA, Carroll CP, Lee G. Spreading Diffusion-Restriction Events in the Gyrencephalic Brain After Subarachnoid Hemorrhage Revealed by Continuous Magnetic Resonance Imaging. Neurocrit Care 2021; 37:60-66. [PMID: 34796429 DOI: 10.1007/s12028-021-01376-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 10/08/2021] [Indexed: 11/28/2022]
Abstract
BACKGROUND How widely spreading depolarizations (SDs) propagate through the gyrencephalic brain, including sulci and deeper cortical areas, remains an important clinical question. Here, we investigated SDs that occur spontaneously after subarachnoid placement of autologous blood clots in sulci of the juvenile swine brain. METHODS To investigate the three-dimensional spread of waves, animals underwent continuous diffusion-weighted magnetic resonance imaging (DW-MRI) for up to 6 h following clot placement. SD is the mechanism of the cytotoxic edema of developing infarction that is diagnosed by DW-MRI, and DW-MRI also captures transient diffusion restriction caused by SD in less injured or healthy brains. Here, images (b = 0, 375, and 750) were acquired across five coronal slices with 1.25 × 1.25-mm in-plane resolution and 5-mm slice thickness, and the protocol was repeated every 6.83-9.15 s. Spatial drift correction, temporal smoothing, and signal intensity normalization were applied to generate videos of diffusion signal intensity changes for each coronal slice. RESULTS Review of video data from five animals revealed ten discrete events consisting of focal diffusion restriction that propagated through cerebral cortex. All events originated in the cortex surrounding the sulcal clot, either in the gyrus (n = 4) or in the sulcal depth (n = 6). In six cases, two to three independent waves spread simultaneously in medial, lateral, and antero-posterior directions. Waves traveled within sulcal walls, traversed the depths of sulci to re-emerge on the adjacent gyrus, and, in three cases, spread fully around the dorsolateral convexity. One event spread deep to olfactory regions along midline cortex, and no events were observed contralateral to the subarachnoid clot. CONCLUSIONS Together, these results suggest that SDs in the injured gyrencephalic brain originate near the injury focus and can spread extensively through the cortex to wide and deep uninjured regions. These findings have implications for transient neurologic deficits in the neurocritically ill patient and relevance to patient monitoring and therapeutics.
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Affiliation(s)
- Jed A Hartings
- Department of Neurosurgery, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
| | - Christopher P Carroll
- Department of Brain and Spinal Surgery, Naval Medical Center Portsmouth, Portsmouth, VA, USA.,Department of Surgery, Uniformed Services University, Bethesda, MD, USA
| | - Gregory Lee
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
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