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Martial C, Piarulli A, Gosseries O, Cassol H, Ledoux D, Charland-Verville V, Laureys S. EEG signature of near-death-like experiences during syncope-induced periods of unresponsiveness. Neuroimage 2024; 298:120759. [PMID: 39067553 DOI: 10.1016/j.neuroimage.2024.120759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 06/28/2024] [Accepted: 07/25/2024] [Indexed: 07/30/2024] Open
Abstract
During fainting, disconnected consciousness may emerge in the form of dream-like experiences. Characterized by extra-ordinary and mystical features, these subjective experiences have been associated to near-death-like experiences (NDEs-like). We here aim to assess brain activity during syncope-induced disconnected consciousness by means of high-density EEG monitoring. Transient loss of consciousness and unresponsiveness were induced in 27 healthy volunteers through hyperventilation, orthostasis, and Valsalva maneuvers. Upon awakening, subjects were asked to report memories, if any. The Greyson NDE scale was used to evaluate the potential phenomenological content experienced during the syncope-induced periods of unresponsiveness. EEG source reconstruction assessed cortical activations during fainting, which were regressed out with subjective reports collected upon recovery of normal consciousness. We also conducted functional connectivity, graph-theoretic and complexity analyses. High quality high-density EEG data were obtained in 22 volunteers during syncope and unresponsiveness (lasting 22±8 s). NDE-like features (Greyson NDE scale total score ≥7/32) were apparent for eight volunteers and characterized by higher activity in delta, theta and beta2 bands in temporal and frontal regions. The richness of the NDE-like content was associated with delta, theta and beta2 bands cortical current densities, in temporal, parietal and frontal lobes, including insula, right temporoparietal junction, and cingulate cortex. Our analyses also revealed a higher complexity and that networks related to delta, theta, and beta2 bands were characterized by a higher overall connectivity paralleled by a higher segregation (i.e., local efficiency) and a higher integration (i.e., global efficiency) for the NDE-like group compared to the non-NDE-like group. Fainting-induced NDE-like episodes seem to be sustained by surges of neural activity representing promising markers of disconnected consciousness.
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Affiliation(s)
- Charlotte Martial
- Coma Science Group, GIGA-Consciousness, University of Liège, Liège, Belgium, Avenue de l'hôpital, 11, 4000 Liège, Belgium; Centre du Cerveau², University Hospital of Liège, Liège, Belgium, Avenue de l'Hôpital, 11, 4000 Liège, Belgium.
| | - Andrea Piarulli
- Coma Science Group, GIGA-Consciousness, University of Liège, Liège, Belgium, Avenue de l'hôpital, 11, 4000 Liège, Belgium; Department of Surgical, Medical, Molecular Pathology and Critical Care Medicine, University of Pisa, Pisa, Italy. Via Paradisa 2, 56124 Pisa, Italy
| | - Olivia Gosseries
- Coma Science Group, GIGA-Consciousness, University of Liège, Liège, Belgium, Avenue de l'hôpital, 11, 4000 Liège, Belgium; Centre du Cerveau², University Hospital of Liège, Liège, Belgium, Avenue de l'Hôpital, 11, 4000 Liège, Belgium
| | - Héléna Cassol
- Coma Science Group, GIGA-Consciousness, University of Liège, Liège, Belgium, Avenue de l'hôpital, 11, 4000 Liège, Belgium
| | - Didier Ledoux
- Centre du Cerveau², University Hospital of Liège, Liège, Belgium, Avenue de l'Hôpital, 11, 4000 Liège, Belgium; Department of Intensive Care and Resuscitation, University Hospital of Liège, Liège, Belgium, Avenue de l'Hôpital, 11, 4000 Liège, Belgium
| | - Vanessa Charland-Verville
- Coma Science Group, GIGA-Consciousness, University of Liège, Liège, Belgium, Avenue de l'hôpital, 11, 4000 Liège, Belgium
| | - Steven Laureys
- Coma Science Group, GIGA-Consciousness, University of Liège, Liège, Belgium, Avenue de l'hôpital, 11, 4000 Liège, Belgium; Centre du Cerveau², University Hospital of Liège, Liège, Belgium, Avenue de l'Hôpital, 11, 4000 Liège, Belgium
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Mahon S. Variation and convergence in the morpho-functional properties of the mammalian neocortex. Front Syst Neurosci 2024; 18:1413780. [PMID: 38966330 PMCID: PMC11222651 DOI: 10.3389/fnsys.2024.1413780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2024] [Accepted: 06/03/2024] [Indexed: 07/06/2024] Open
Abstract
Man's natural inclination to classify and hierarchize the living world has prompted neurophysiologists to explore possible differences in brain organisation between mammals, with the aim of understanding the diversity of their behavioural repertoires. But what really distinguishes the human brain from that of a platypus, an opossum or a rodent? In this review, we compare the structural and electrical properties of neocortical neurons in the main mammalian radiations and examine their impact on the functioning of the networks they form. We discuss variations in overall brain size, number of neurons, length of their dendritic trees and density of spines, acknowledging their increase in humans as in most large-brained species. Our comparative analysis also highlights a remarkable consistency, particularly pronounced in marsupial and placental mammals, in the cell typology, intrinsic and synaptic electrical properties of pyramidal neuron subtypes, and in their organisation into functional circuits. These shared cellular and network characteristics contribute to the emergence of strikingly similar large-scale physiological and pathological brain dynamics across a wide range of species. These findings support the existence of a core set of neural principles and processes conserved throughout mammalian evolution, from which a number of species-specific adaptations appear, likely allowing distinct functional needs to be met in a variety of environmental contexts.
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Affiliation(s)
- Séverine Mahon
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, Paris, France
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Salari N, Karimi Z, Hemmati M, Mohammadi A, Shohaimi S, Mohammadi M. Global prevalence of vasovagal syncope: A systematic review and meta-analysis. GLOBAL EPIDEMIOLOGY 2024; 7:100136. [PMID: 38283939 PMCID: PMC10821537 DOI: 10.1016/j.gloepi.2024.100136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 11/18/2023] [Accepted: 01/04/2024] [Indexed: 01/30/2024] Open
Abstract
Background Today, vasovagal syncope is a common problem that has become a significant health and social challenge. The present study investigated the global prevalence of vasovagal syncope using a systematic review and meta-analysis.Methods: In this systematic review and meta-analysis study, the global prevalence of vasovagal syncope using the keywords Prevalence, Epidemiology, Vasovagal syncope, and Reflex syncope in PubMed, WoS, Scopus, ScienceDirect databases, and Google scholar search engine without time limit until July 20, 2022, was extracted and transferred to the information management software (EndNote). Then the repeated studies were excluded, and researchers evaluated the remaining studies during three stages (i.e., screening, eligibility, and qualitative assessment). The heterogeneity of studies was investigated using the I2 index, and the analysis of eligible studies was performed using the random effects model. Results In the review of 12 studies with a sample size of 36,156 people, the global prevalence of vasovagal syncope was reported as 16.4 (95%CI: 6-37.5), and the study of publication bias in the studies through the Egger test shows the absence of publication bias in the studies. Conclusion The prevalence reported in the studies shows a high prevalence of vasovagal syncope, which requires serious intervention and preventive, diagnostic, and therapeutic measures. It is necessary for health policymakers to take effective measures in this field.
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Affiliation(s)
- Nader Salari
- Department of Biostatistics, School of Health, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Zohre Karimi
- Student Research Committee, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Mahvan Hemmati
- Student Research Committee, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Ali Mohammadi
- Student Research Committee, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Shamarina Shohaimi
- Department of Biology, Faculty of Science, University Putra Malaysia, Serdang, Selangor, Malaysia
| | - Masoud Mohammadi
- Cellular and Molecular Research Center, Gerash University of Medical Sciences, Gerash, Iran
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Tajdini M, Khalaji A, Behnoush AH, Tavolinejad H, Jalali A, Sadeghian S, Vasheghani-Farahani A, Yadangi S, Masoudkabir F, Bozorgi A. Brain MRI and EEG overemployment in patients with vasovagal syncope: results from a tertiary syncope unit. BMC Cardiovasc Disord 2023; 23:576. [PMID: 37990291 PMCID: PMC10664686 DOI: 10.1186/s12872-023-03615-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 11/15/2023] [Indexed: 11/23/2023] Open
Abstract
BACKGROUND The diagnosis of vasovagal syncope (VVS) is mainly based on history-taking and physical examination. However, brain Magnetic Resonance Imaging (MRI) and Electroencephalogram (EEG) are commonly used in the diagnostic course of VVS, despite not being indicated in the guidelines. This study aims to find the possible associated factors with the administration of brain MRI and EEG in patients with VVS. METHODS Patients with a diagnosis of VVS from 2017 to 2022 were included. Several demographic and syncope features were recorded. The association of these was assessed with undergoing MRI, EEG, and either MRI or EEG. Univariate and multivariable logistic regression models were also used to calculate odds ratios (OR) and 95% confidence intervals (CI). RESULTS A total of 1882 patients with VVS were analyzed, among which 810 underwent MRI (43.04%), 985 underwent EEG (52.34%), and 1166 underwent MRI or EEG (61.96%). Head trauma (OR 1.38, 95% CI 1.06 to 1.80), previous neurologist visit (OR 6.28, 95% CI 4.24 to 9.64), and gaze disturbance during syncope (OR 1.75, 95% CI 1.13 to 2.78) were all positively associated to the performance of brain MRI/EEG. Similar results were found for urinary incontinence (OR 2.415, 95% CI 1.494 to 4.055), amnesia (OR 1.421, 95% CI 1.053 to 1.930), headache after syncope (OR 1.321, 95% CI 1.046 to 1.672), and tonic-clonic movements in head-up tilt table test (OR 1.501, 95% CI 1.087 to 2.093). However, male sex (OR 0.655, 95% CI 0.535 to 0.800) and chest pain before syncope (OR 0.628, 95% CI 0.459 to 0.860) had significant negative associations with performing brain MRI/EEG. CONCLUSION Based on our findings, performing MRI or EEG was common among VVS patients while it is not indicated in the majority of cases. This should be taken into consideration to prevent inappropriate MRI/EEG when there is a typical history compatible with VVS.
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Affiliation(s)
- Masih Tajdini
- Cardiovascular Diseases Research Institute, Tehran Heart Center, Tehran University of Medical Sciences, Tehran, Iran
- Cardiac Primary Prevention Research Center, Cardiovascular Diseases Research Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Amirmohammad Khalaji
- Cardiovascular Diseases Research Institute, Tehran Heart Center, Tehran University of Medical Sciences, Tehran, Iran.
- Cardiac Primary Prevention Research Center, Cardiovascular Diseases Research Institute, Tehran University of Medical Sciences, Tehran, Iran.
- School of Medicine, Tehran University of Medical Sciences, Poursina St., Keshavarz Blvd, Tehran, 1416634793, Iran.
| | - Amir Hossein Behnoush
- Cardiovascular Diseases Research Institute, Tehran Heart Center, Tehran University of Medical Sciences, Tehran, Iran
- Cardiac Primary Prevention Research Center, Cardiovascular Diseases Research Institute, Tehran University of Medical Sciences, Tehran, Iran
- School of Medicine, Tehran University of Medical Sciences, Poursina St., Keshavarz Blvd, Tehran, 1416634793, Iran
| | - Hamed Tavolinejad
- Cardiovascular Diseases Research Institute, Tehran Heart Center, Tehran University of Medical Sciences, Tehran, Iran
- Cardiac Primary Prevention Research Center, Cardiovascular Diseases Research Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Arash Jalali
- Cardiac Primary Prevention Research Center, Cardiovascular Diseases Research Institute, Tehran University of Medical Sciences, Tehran, Iran
- Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Saeed Sadeghian
- Cardiovascular Diseases Research Institute, Tehran Heart Center, Tehran University of Medical Sciences, Tehran, Iran
- Cardiac Primary Prevention Research Center, Cardiovascular Diseases Research Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Ali Vasheghani-Farahani
- Cardiovascular Diseases Research Institute, Tehran Heart Center, Tehran University of Medical Sciences, Tehran, Iran
- Cardiac Primary Prevention Research Center, Cardiovascular Diseases Research Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Somayeh Yadangi
- Cardiovascular Diseases Research Institute, Tehran Heart Center, Tehran University of Medical Sciences, Tehran, Iran
- Cardiac Primary Prevention Research Center, Cardiovascular Diseases Research Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Farzad Masoudkabir
- Cardiovascular Diseases Research Institute, Tehran Heart Center, Tehran University of Medical Sciences, Tehran, Iran
- Cardiac Primary Prevention Research Center, Cardiovascular Diseases Research Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Ali Bozorgi
- Cardiovascular Diseases Research Institute, Tehran Heart Center, Tehran University of Medical Sciences, Tehran, Iran
- Cardiac Primary Prevention Research Center, Cardiovascular Diseases Research Institute, Tehran University of Medical Sciences, Tehran, Iran
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Lovelace JW, Ma J, Yadav S, Chhabria K, Shen H, Pang Z, Qi T, Sehgal R, Zhang Y, Bali T, Vaissiere T, Tan S, Liu Y, Rumbaugh G, Ye L, Kleinfeld D, Stringer C, Augustine V. Vagal sensory neurons mediate the Bezold-Jarisch reflex and induce syncope. Nature 2023; 623:387-396. [PMID: 37914931 PMCID: PMC10632149 DOI: 10.1038/s41586-023-06680-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 09/26/2023] [Indexed: 11/03/2023]
Abstract
Visceral sensory pathways mediate homeostatic reflexes, the dysfunction of which leads to many neurological disorders1. The Bezold-Jarisch reflex (BJR), first described2,3 in 1867, is a cardioinhibitory reflex that is speculated to be mediated by vagal sensory neurons (VSNs) that also triggers syncope. However, the molecular identity, anatomical organization, physiological characteristics and behavioural influence of cardiac VSNs remain mostly unknown. Here we leveraged single-cell RNA-sequencing data and HYBRiD tissue clearing4 to show that VSNs that express neuropeptide Y receptor Y2 (NPY2R) predominately connect the heart ventricular wall to the area postrema. Optogenetic activation of NPY2R VSNs elicits the classic triad of BJR responses-hypotension, bradycardia and suppressed respiration-and causes an animal to faint. Photostimulation during high-resolution echocardiography and laser Doppler flowmetry with behavioural observation revealed a range of phenotypes reflected in clinical syncope, including reduced cardiac output, cerebral hypoperfusion, pupil dilation and eye-roll. Large-scale Neuropixels brain recordings and machine-learning-based modelling showed that this manipulation causes the suppression of activity across a large distributed neuronal population that is not explained by changes in spontaneous behavioural movements. Additionally, bidirectional manipulation of the periventricular zone had a push-pull effect, with inhibition leading to longer syncope periods and activation inducing arousal. Finally, ablating NPY2R VSNs specifically abolished the BJR. Combined, these results demonstrate a genetically defined cardiac reflex that recapitulates characteristics of human syncope at physiological, behavioural and neural network levels.
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Affiliation(s)
- Jonathan W Lovelace
- Department of Neurobiology, University of California, San Diego, CA, USA
- Department of Neuroscience, Scripps Research, La Jolla, CA, USA
| | - Jingrui Ma
- Department of Neurobiology, University of California, San Diego, CA, USA
- Department of Neuroscience, Scripps Research, La Jolla, CA, USA
| | - Saurabh Yadav
- Department of Neurobiology, University of California, San Diego, CA, USA
- Department of Neuroscience, Scripps Research, La Jolla, CA, USA
| | | | - Hanbing Shen
- Department of Neuroscience, Scripps Research, La Jolla, CA, USA
| | - Zhengyuan Pang
- Department of Neuroscience, Scripps Research, La Jolla, CA, USA
| | - Tianbo Qi
- Department of Neuroscience, Scripps Research, La Jolla, CA, USA
| | - Ruchi Sehgal
- Department of Neuroscience, Scripps Research, La Jolla, CA, USA
| | - Yunxiao Zhang
- Department of Neuroscience, Scripps Research, La Jolla, CA, USA
| | - Tushar Bali
- Department of Neuroscience, Scripps Research, La Jolla, CA, USA
| | - Thomas Vaissiere
- University of Florida-Scripps Biomedical Research, Jupiter, FL, USA
| | - Shawn Tan
- Department of Neuroscience, Scripps Research, La Jolla, CA, USA
| | - Yuejia Liu
- Department of Neuroscience, Scripps Research, La Jolla, CA, USA
| | - Gavin Rumbaugh
- University of Florida-Scripps Biomedical Research, Jupiter, FL, USA
| | - Li Ye
- Department of Neuroscience, Scripps Research, La Jolla, CA, USA
| | - David Kleinfeld
- Department of Neurobiology, University of California, San Diego, CA, USA
- Department of Physics, University of California, San Diego, CA, USA
| | | | - Vineet Augustine
- Department of Neurobiology, University of California, San Diego, CA, USA.
- Department of Neuroscience, Scripps Research, La Jolla, CA, USA.
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Toprani S, Jaradeh S, Falco-Walter JJ. Epileptic Seizure Induced by Head-Up Tilt: A Case Series Study. J Clin Neurophysiol 2023; 40:582-588. [PMID: 35394972 DOI: 10.1097/wnp.0000000000000926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
PURPOSE Epilepsy and syncope can be difficult to distinguish, with misdiagnosis resulting in unnecessary or incorrect treatment and disability. Combined tilt-table and video EEG (vEEG) testing (tilt-vEEG) is infrequently used to parse these entities even at large centers. Because of the discovery of a rare case of epileptic seizure induced by head-up tilt (HUT) (no prior cases have been published), the authors sought to verify the rarity of this phenomenon. METHODS An observational, retrospective case series study of all combined tilt-vEEG studies performed at Stanford Health Care over a 2-year period was performed. Studies were grouped into categories: (1) abnormal tilt and normal vEEG; (2) abnormal vEEG and normal tilt; (3) abnormal vEEG and abnormal tilt; (4) normal tilt and normal vEEG, with neurologic symptoms; and (5) normal tilt and normal vEEG without neurologic symptoms. RESULTS Sixty-eight percent of patients had an abnormal study (categories A-C), with only 3% having both an abnormal tilt and an abnormal EEG (category C). Of these, one patient had a focal epileptic seizure induced by HUT. With HUT positioning, the patient stopped answering questions and vEEG showed a left temporal seizure; systolic blood pressure abruptly dropped to 89 mm Hg (64 mm Hg below baseline); heart rate did not change, but pacemaker showed increased firing (threshold: <60 bpm). CONCLUSIONS Combined tilt-table and vEEG evaluation was able to identify a previously unreported scenario-head-up tilt provocation of an epileptic seizure-and improve treatment. Combined tilt and vEEG testing should be considered for episodes that persist despite treatment to confirm proper diagnosis.
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Affiliation(s)
- Sheela Toprani
- Department of Neurology, Division of Epilepsy, Stanford University Medical Center, Stanford, California, U.S.A
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Tozzi A. Laws of taxation for multicellular organisms: The economics of sleep. Biosystems 2023; 232:105018. [PMID: 37666410 DOI: 10.1016/j.biosystems.2023.105018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 08/30/2023] [Accepted: 08/30/2023] [Indexed: 09/06/2023]
Abstract
In macro-public finance, the Ramsey rule (RR) concerns variable taxation to maximize social welfare and economic efficiency in a purely competitive monopolistic system. To extract tax revenue with the least loss of utility to the representative individual, RR dictates that optimal, proportionate taxes should be such as to diminish in the same proportion the production of each commodity taxed. The sources of supply that are inelastic, i.e., necessities/utilities, must be taxed more. We hypothesize that the Ramsey's economical approach might provide a general mechanism to investigate far-flung biological issues, such as preys/predators dynamics, food restriction in ecological niches, local changes in blood flow in rival or complementary organs of multicellular organisms. In particular, RR suggests a quantifiable relationship between the physiological decrease in cortical spike frequency occurring during sleep and energy consumption. Since small decreases in spike frequency during sleep are correlated with large decreases in the amount of consumed ATP, the brain could be considered an inelastic commodity which can be "taxed" more than other organs, allowing the whole organism to spare energy. Shedding light on the energy budget of the central nervous system, RR improves our knowledge of cerebral perfusion during sensory-evoked responses and tissue hypoxia caused by decreased blood flow, suggesting that energy from outside can be provided to counteract brain ischemia. In sum, the economical approach provided by Ramsey stands for a useful methodological tool that could be used in biological contexts to investigate the dynamical correlations among different organs in multicellular organisms.
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Affiliation(s)
- Arturo Tozzi
- Center for Nonlinear Science, Department of Physics, University of North Texas, 1155 Union Circle, #311427, Denton, TX, 76203-5017, USA.
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8
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Charpier S. Between life and death: the brain twilight zones. Front Neurosci 2023; 17:1156368. [PMID: 37260843 PMCID: PMC10227869 DOI: 10.3389/fnins.2023.1156368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 04/24/2023] [Indexed: 06/02/2023] Open
Abstract
Clinically, and legally, death is considered a well-defined state of the organism characterized, at least, by a complete and irreversible cessation of brain activities and functions. According to this pragmatic approach, the moment of death is implicitly represented by a discrete event from which all cerebral processes abruptly cease. However, a growing body of experimental and clinical evidence has demonstrated that cardiorespiratory failure, the leading cause of death, causes complex time-dependent changes in neuronal activity that can lead to death but also be reversed with successful resuscitation. This review synthesizes our current knowledge of the succeeding alterations in brain activities that accompany the dying and resuscitation processes. The anoxia-dependent brain defects that usher in a process of potential death successively include: (1) a set of changes in electroencephalographic (EEG) and neuronal activities, (2) a cessation of brain spontaneous electrical activity (isoelectric state), (3) a loss of consciousness whose timing in relation to EEG changes remains unclear, (4) an increase in brain resistivity, caused by neuronal swelling, concomitant with the occurrence of an EEG deviation reflecting the neuronal anoxic insult (the so-called "wave of death," or "terminal spreading depolarization"), followed by, (5) a terminal isoelectric brain state leading to death. However, a timely restoration of brain oxygen supply-or cerebral blood flow-can initiate a mirrored sequence of events: a repolarization of neurons followed by a re-emergence of neuronal, synaptic, and EEG activities from the electrocerebral silence. Accordingly, a recent study has revealed a new death-related brain wave: the "wave of resuscitation," which is a marker of the collective recovery of electrical properties of neurons at the beginning of the brain's reoxygenation phase. The slow process of dying still represents a terra incognita, during which neurons and neural networks evolve in uncertain states that remain to be fully understood. As current event-based models of death have become neurophysiologically inadequate, I propose a new mixed (event-process) model of death and resuscitation. It is based on a detailed description of the different phases that succeed each other in a dying brain, which are generally described separately and without mechanistic linkage, in order to integrate them into a continuum of declining brain activity. The model incorporates cerebral twilight zones (with still unknown neuronal and synaptic processes) punctuated by two characteristic cortical waves providing real-time biomarkers of death- and resuscitation.
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Affiliation(s)
- Stéphane Charpier
- Sorbonne Université, Institut du Cerveau – Paris Brain Institute - ICM, Inserm, CNRS, APHP, Hôpital de la Pitié-Salpêtriére, Paris, France
- Sorbonne University, UPMC Université Paris, Paris, France
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Poothrikovil RP, Al Mashaikhi T. Vasovagal Syncope in Epilepsy Monitoring Unit: A Case Report and Review. Neurodiagn J 2021; 61:132-143. [PMID: 34449291 DOI: 10.1080/21646821.2021.1933862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Falls are a common adverse event (AE) in general hospital admissions and in the epilepsy monitoring unit (EMU) and can cause serious physical injury for patients; however, fall prevention policies widely vary between epilepsy centers. Patient safety, including minimizing AEs, such as falls, continue to be a major goal of quality improvement in the EMU. The bathroom area in an EMU is highly prone for falls due to the need for patient privacy. Syncope is a physiologic non-epileptic event with high prevalence in general population and is a potential cause for fall. It is also reported in people diagnosed with epilepsy. We report a case of vasovagal syncope (VVS) associated with injury in a young female during long-term video EEG recording in our EMU facility. We also briefly address concerns for identifying patients at risk for syncope and its prevention. A multidisciplinary team including EEG technologists can play a vital role in educating patients and caretakers about the risk factors of syncopal fall and its preventive measures.
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Affiliation(s)
- Rajesh P Poothrikovil
- Department of Clinical PhysiologySultan Qaboos University Hospital, Muscat, Sultanate of Oman
| | - Talal Al Mashaikhi
- Department of Clinical PhysiologySultan Qaboos University Hospital, Muscat, Sultanate of Oman
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Siddiqi AZ, Blackmore D, Siddiqi ZA. "Complex" Vasovagal Syncope: A Zebra Among Horses. Front Neurol 2021; 11:550982. [PMID: 33391141 PMCID: PMC7772312 DOI: 10.3389/fneur.2020.550982] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 10/08/2020] [Indexed: 11/23/2022] Open
Abstract
Background: Vasovagal syncope (VVS) occurs due to cerebral hypoperfusion from a fall in blood pressure, with accompanying bradycardia in most cases. Seizure and/or asystole may accompany VVS, though their prediction within the VVS cohort remains elusive. Objective: To further characterize VVS and to find predictive features of “complex” VVS (defined as VVS associated with seizures and/or asystole). Methods: We reviewed medical records of all patients who were referred for orthostatic intolerance and had a definite VVS during the head-up tilt table testing (HUTT). The following variables were recorded: cardiovascular indices during HUTT, autonomic testing results, and semiology of asystole and/or seizure when present. Simple frequency and correlation analysis were performed using the ANOVA. Results: A total of 78 independent VVS were recorded in 60 patients of which 24% were not preceded by presyncope. Vasodepressor (45%) and mixed (38%) VVS were the most prevalent types. Eighteen (23%) were complex VVS; five had an associated seizure (SySz), nine were accompanied by asystole (SyAs), and four had both (SySzAs). Males were significantly more likely to have complex VVS. Mean asystole duration was somewhat longer in the SyAsSz group. The severity of bradycardia significantly correlated with complex VVS and was a predictor of SySz. Autonomic abnormalities were frequent but did not distinguish the two VVS subgroups. Seizures had multiple distinguishing features from those typically associated with epileptic seizures. Conclusions: The underlying pathophysiologic mechanisms of complex VVS remain unclear, but the severity of cerebral hypoperfusion due to bradycardia likely plays a key role in seizure generation.
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Affiliation(s)
- Anwer Zohaib Siddiqi
- Division of Neurology, Department of Medicine, University of Alberta, Edmonton, AB, Canada
| | - Derrick Blackmore
- Division of Neurology, Department of Medicine, University of Alberta, Edmonton, AB, Canada
| | - Zaeem Azfer Siddiqi
- Division of Neurology, Department of Medicine, University of Alberta, Edmonton, AB, Canada
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Vaksmann G, Bouzguenda I, Lamblin MD. The slow-flat-slow sequence in malignant vasovagal syncope. Ann Pediatr Cardiol 2020; 14:128-129. [PMID: 33679080 PMCID: PMC7918025 DOI: 10.4103/apc.apc_105_20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 08/30/2020] [Accepted: 09/21/2020] [Indexed: 11/04/2022] Open
Abstract
We present the electroencephalographic and electrocardiographic tracing obtained in an 8-year old boy who experienced malignant vasovagal syncope during the recording. This tracing illustrates the highly specific "slow-flat-slow" sequence described in cases of syncope induced by severe cerebral hypoperfusion.
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Affiliation(s)
- Guy Vaksmann
- Department of Pediatric Cardiology, Hôpital Privé de La Louvière, Lille, France
| | - Ivan Bouzguenda
- Department of Pediatric Cardiology, Hôpital Privé de La Louvière, Lille, France
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Aebi MR, Bourdillon N, Meziane HB, Nicol E, Barral J, Millet GP, Bron D. Cardiovascular and Cerebral Responses During a Vasovagal Reaction Without Syncope. Front Neurosci 2019; 13:1315. [PMID: 31920485 PMCID: PMC6914691 DOI: 10.3389/fnins.2019.01315] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 11/25/2019] [Indexed: 01/29/2023] Open
Abstract
This clinical case report presents synchronous physiological data from an individual in whom a spontaneous vasovagal reaction occurred without syncope. The physiological data are presented for three main phases: Baseline (0–200 s), vasovagal reaction (200–600 s), and recovery period (600–1200 s). The first physiological changes occurred at around 200 s, with a decrease in blood pressure, peak in heart rate and vastus lateralis tissue oxygenation, and a drop in alpha power. The vasovagal reaction was associated with a progressive decrease in blood pressure, heart rate and cerebral oxygenation, whilst the mean middle cerebral artery blood flow velocity and blood oxygen saturation remained unchanged. Heart rate variability parameters indicated significant parasympathetic activation with a decrease in sympathetic tone and increased baroreflex sensitivity. The total blood volume and tissue oxygenation index (TOI) dropped in the brain but slightly increased in the vastus lateralis, suggesting cerebral hypoperfusion with blood volume pooling in the lower body part. Cerebral hypoperfusion during the vasovagal reaction was associated with electroencephalography (EEG) flattening (i.e., decreased power in beta and theta activity) followed by an EEG high-amplitude “slow” phase (i.e., increased power in theta activity). The subject developed signs and symptoms of pre-syncope with EEG flattening and slowing during prolonged periods of symptomatic hypotension, but did not lose consciousness.
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Affiliation(s)
- Mathias R Aebi
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland.,Aeromedical Center (AeMC), Swiss Air Force, Dübendorf, Switzerland
| | - Nicolas Bourdillon
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Hadj B Meziane
- Institute of Psychology, Faculty of Social and Political Sciences, University of Lausanne, Lausanne, Switzerland
| | - Edward Nicol
- Aviation Medicine Clinical Service, RAF Centre of Aviation Medicine, RAF Henlow, Bedfordshire, United Kingdom
| | - Jérôme Barral
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Grégoire P Millet
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Denis Bron
- Aeromedical Center (AeMC), Swiss Air Force, Dübendorf, Switzerland
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Heyer GL, Held T, Islam MP. Quantitative electroencephalography characteristics of tilt-induced neurally-mediated syncope among youth. Clin Neurophysiol 2019; 130:752-758. [DOI: 10.1016/j.clinph.2019.02.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 01/05/2019] [Accepted: 02/13/2019] [Indexed: 01/08/2023]
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14
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Ninni S, Kouakam C, Szurhaj W, Baille G, Klug D, Lacroix D, Derambure P. Usefulness of head-up tilt test combined with video electroencephalogram to investigate recurrent unexplained atypical transient loss of consciousness. Arch Cardiovasc Dis 2019; 112:82-94. [PMID: 30600217 DOI: 10.1016/j.acvd.2018.08.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 08/17/2018] [Indexed: 11/28/2022]
Abstract
BACKGROUND Convulsive syncope and epileptic seizure share many similar clinical features. Early diagnosis is critical for choosing the appropriate management strategy. AIM Our aim was to evaluate the diagnostic yield of an innovative diagnostic strategy - combined head-up tilt test (HUT)/video electroencephalogram (EEG) monitoring - in patients with unexplained seizure-like transient loss of consciousness (T-LOC). METHODS Combined HUT/video EEG was performed in patients with unexplained atypical T-LOC with both syncope and seizure characteristics remaining undiagnosed after a first-line investigation. T-LOC diagnosis was achieved in case of reproduction of usual symptoms. Events were classified as vasovagal, psychogenic or epilepsy. The link between EEG abnormalities and T-LOC was determined by an epilepsy specialist. Clinical follow-up was performed to assess T-LOC recurrence. RESULTS Hundred and one consecutive patients were prospectively enrolled (median age 26 [19; 46] years; 72% female) and underwent combined HUT/video EEG between 2007 and 2015. Antiepileptic drugs were being prescribed in 42% of patients. Combined HUT/video EEG was diagnostic in 67% of patients, leading to diagnosis of vasovagal syncope in 59 patients and psychogenic pseudosyncope in nine cases. Antiepileptic drugs were discontinued in 18 patients without epilepsy. Independent predictors of a definitive diagnosis were the presence of prodromal symptoms (odds ratio 5.97, 95% confidence interval 1.37-26; P=0.017) and a history of myoclonic jerks during T-LOC (odds ratio 4.36, 95% confidence interval 1.71-11.15; P=0.002). CONCLUSIONS Combined HUT/video EEG is useful for investigating recurrent unexplained atypical seizure-like T-LOC, especially in patients with a history of myoclonic jerks or with documented interictal non-specific EEG abnormalities.
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Affiliation(s)
- Sandro Ninni
- Clinique cardiologique, Institut Cœur-Poumon, CHRU de Lille, boulevard du Professeur-Jules-Leclercq, 59037 Lille, France.
| | - Claude Kouakam
- Clinique cardiologique, Institut Cœur-Poumon, CHRU de Lille, boulevard du Professeur-Jules-Leclercq, 59037 Lille, France
| | - William Szurhaj
- Service de neurophysiologie clinique, hôpital Roger-Salengro, CHRU de Lille, avenue du Professeur-Emile-Laine, 59037 Lille, France
| | - Guillaume Baille
- Service de neurophysiologie clinique, hôpital Roger-Salengro, CHRU de Lille, avenue du Professeur-Emile-Laine, 59037 Lille, France
| | - Didier Klug
- Clinique cardiologique, Institut Cœur-Poumon, CHRU de Lille, boulevard du Professeur-Jules-Leclercq, 59037 Lille, France
| | - Dominique Lacroix
- Clinique cardiologique, Institut Cœur-Poumon, CHRU de Lille, boulevard du Professeur-Jules-Leclercq, 59037 Lille, France
| | - Philippe Derambure
- Service de neurophysiologie clinique, hôpital Roger-Salengro, CHRU de Lille, avenue du Professeur-Emile-Laine, 59037 Lille, France
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Joo BE, Koo DL, Yim HR, Park J, Seo DW, Kim JS. Seizure-like activities in patients with head-up tilt test-induced syncope. Medicine (Baltimore) 2018; 97:e13602. [PMID: 30572468 PMCID: PMC6320058 DOI: 10.1097/md.0000000000013602] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The purpose of this study was to assess the prevalence and the characteristics of seizure-like activities during head-up tilt test (HUT)-induced syncope, in patients with suspected vasovagal syncope (VVS). We also evaluated the differences in hemodynamic parameters between patients with and without seizure-like activities.A total of 71 patients with suspected VVS, who showed syncope during HUT between October 2010 and May 2013, were analyzed. Electrocardiogram and hemodynamic parameters were continuously monitored during HUT. We also performed video recording of patients during HUT to identify eyeball deviation or seizure-like limb movements.In all, 47 patients (66.2%) showed seizure-like activities at the time of syncope during HUT, 14 patients presented eyeball deviation, without abnormal limb movements, and 33 patients showed abnormal limb movements, such as myoclonic or tonic-clonic activities, as well as eyeball deviation. Upon comparison of the 2 groups with or without seizure-like activities, patients showing seizure-like activities presented a significantly lower heart rate at the time of syncope in HUT (38.51 ± 16.81 vs 49.67 ± 20.12, P < .05). Also, upon comparison within patients showing seizure-like activities, the patients who showed abnormal limb movements with eyeball deviation demonstrated a significantly lower systolic blood pressure and cardiac output at the time of syncope (34.30 ± 12.24 vs 49.00 ± 14.14, P < .05; 0.58 ± 0.40 vs 1.32 ± 0.97, P < .05).Seizure-like activities were observed in high percentage in about 66% of patients during HUT-induced syncope. The occurrence of seizure-like activities was associated with more severe transient hemodynamic changes, such as lower heart rate, systolic blood pressure, and cardiac output at the time of the HUT-induced syncope.
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Affiliation(s)
- Byung-Euk Joo
- Department of Neurology, Myongji Hospital, Hanyang University College of Medicine, Gyeonggi-do
| | - Dae Lim Koo
- Department of Neurology, Seoul Metropolitan Government Boramae Medical Center, Seoul National University College of Medicine
| | - Hye Ran Yim
- Division of Cardiology, Department of Medicine, Heart Stroke Vascular Institute
| | - Jungwae Park
- Division of Cardiology, Department of Medicine, Heart Stroke Vascular Institute
| | - Dae-Won Seo
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - June Soo Kim
- Division of Cardiology, Department of Medicine, Heart Stroke Vascular Institute
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17
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2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope: Executive summary. Heart Rhythm 2017; 14:e218-e254. [DOI: 10.1016/j.hrthm.2017.03.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Indexed: 01/05/2023]
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18
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Shen WK, Sheldon RS, Benditt DG, Cohen MI, Forman DE, Goldberger ZD, Grubb BP, Hamdan MH, Krahn AD, Link MS, Olshansky B, Raj SR, Sandhu RK, Sorajja D, Sun BC, Yancy CW. 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope: A report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Heart Rhythm 2017; 14:e155-e217. [PMID: 28286247 DOI: 10.1016/j.hrthm.2017.03.004] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Indexed: 12/26/2022]
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19
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Shen WK, Sheldon RS, Benditt DG, Cohen MI, Forman DE, Goldberger ZD, Grubb BP, Hamdan MH, Krahn AD, Link MS, Olshansky B, Raj SR, Sandhu RK, Sorajja D, Sun BC, Yancy CW. 2017 ACC/AHA/HRS Guideline for the Evaluation and Management of Patients With Syncope: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. J Am Coll Cardiol 2017; 70:620-663. [PMID: 28286222 DOI: 10.1016/j.jacc.2017.03.002] [Citation(s) in RCA: 105] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Heyer GL, Schmittauer C, Islam MP. The Clinical and Electroencephalographic Spectrum of Tilt-Induced Syncope and "Near Syncope" in Youth. Pediatr Neurol 2016; 62:27-33. [PMID: 27436539 DOI: 10.1016/j.pediatrneurol.2016.05.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 05/13/2016] [Accepted: 05/14/2016] [Indexed: 10/21/2022]
Abstract
BACKGROUND The aim of the study was to characterize the clinical and electroencephalographic (EEG) patterns associated with tilt-induced reflex syncope and delayed orthostatic hypotension without syncope in youth. METHODS We conducted a prospective observational study of 95 patients referred to a pediatric neurology clinic for head-upright tilt testing. Clinical signs, symptoms, video EEG, and continuous blood pressure and heart rate were monitored. RESULTS Eighty patients had reflex syncope, and 15 had delayed-onset hypotension without syncope. The mean age was 15.3 (standard deviation ±2.3) years; 75 (78.9%) were female. All patients with hypotension only had corresponding signs and symptoms; 13 (86.7%) had corresponding EEG slowing. The duration of EEG slowing with hypotension far exceeded the presyncope interval from onset of slowing to loss of consciousness among patients with syncope (P < 0.001). Although prior near-syncope and presyncope episodes were reported commonly in both groups, patients with delayed hypotension without syncope were less likely to have experienced loss of consciousness during episodes of orthostatic intolerance (P < 0.001). Patients with syncope had either slow-flat-slow (n = 23) or slow-only (n = 57) EEG patterns. Compared to those with slow-only EEG patterns, patients with the slow-flat-slow pattern had greater rates of asystole (P < 0.001), myoclonic movements (P < 0.001), facial grimace (P = 0.003), vocalizations (P = 0.002), and arm flexion (P < 0.001) or extension (P = 0.006) during tilt-induced syncope. CONCLUSIONS Among otherwise healthy youth, orthostatic signs and symptoms vary across the spectrum of tilt-induced reflex syncope and delayed hypotension without syncope. Delayed hypotension without syncope may represent the poorly defined phenomenon of "near syncope" in some patients.
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Affiliation(s)
- Geoffrey L Heyer
- Division of Pediatric Neurology, Nationwide Children's Hospital, Columbus, Ohio; Department of Pediatrics, The Ohio State University, Columbus, Ohio; Department of Neurology, The Ohio State University, Columbus, Ohio.
| | | | - Monica P Islam
- Division of Pediatric Neurology, Nationwide Children's Hospital, Columbus, Ohio; Department of Pediatrics, The Ohio State University, Columbus, Ohio; Department of Neurology, The Ohio State University, Columbus, Ohio
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21
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Sweat patterns differ between tilt-induced reflex syncope and tilt-induced anxiety among youth. Clin Auton Res 2016; 26:295-302. [DOI: 10.1007/s10286-016-0368-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 06/21/2016] [Indexed: 11/27/2022]
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22
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Blanc JJ, Benditt DG. Vasovagal Syncope: Hypothesis Focusing on Its Being a Clinical Feature Unique to Humans. J Cardiovasc Electrophysiol 2016; 27:623-9. [PMID: 26840192 DOI: 10.1111/jce.12945] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 01/06/2016] [Accepted: 01/25/2016] [Indexed: 11/28/2022]
Abstract
Humans live primarily in the upright position; as a result, there is a constant struggle between gravity and needed supply of blood flow to the brain. In certain circumstances brain blood supply may become temporarily insufficient, resulting in syncope. Among the numerous causes of syncope in humans, vasovagal syncope (VVS) is by far the most common. However, despite intensive research, many aspects of the pathophysiology of VVS remain unknown; among these, one of the least well understood is the basis for why VVS is restricted, among vertebrates, to Homo sapiens. In this manuscript we review proposals that have been offered in an attempt to address the issue of the origin of VVS and, although highly speculative, we suggest a new hypothesis (the "brain theory") to try to address the question of why humans, to the exclusion of other species, remain susceptible to VVS. This theory suggests that VVS evolved to offer protection to the brain's functional integrity under certain conditions of severe threat. Although seemingly a disadvantageous evolutionary adaptation, the faint causes the body to take on a gravitationally neutral position, and thereby provides a better chance of restoring brain blood supply and preserving long-term brain function.
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Affiliation(s)
| | - David G Benditt
- The Cardiac Arrhythmia Center, University of Minnesota Medical School, Minneapolis, Minnesota, USA
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Abstract
In the investigation of psychogenic nonepileptic seizures (PNES), the main differential diagnoses are between convulsive PNES and tonic-clonic seizures, between swoon PNES and syncope, and between pseudoabsence PNES and absence seizures. For the best diagnostic certainty, events must be captured, ideally using video-electroencephalogram (EEG), including an electrocardiographic channel. The "video" part of video-EEG allows EEG changes (or lack of them) to be interpreted in the appropriate clinical context. When the diagnosis is based on less good data (e.g., video alone or EEG alone), then the limitations and constraints of the tests should borne in mind, and a lesser degree of certainty must be accepted. Tests such as serum prolactin (PRL) level and postictal EEG should be regarded as adjunctive rather than definitive. Excluding additional epilepsy with a good probability is not possible using investigations alone. In particular, one standard interictal EEG recording is of little value in excluding additional epilepsy, though multiple or prolonged recordings may offer additional sensitivity.
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Affiliation(s)
- R Duncan
- Department of Neurology, University of Otago and Department of Neurology, Christchurch Hospital, Christchurch, New Zealand.
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Zyśko D, Fedorowski A, Nilsson D, Rudnicki J, Gajek J, Melander O, Sutton R. Tilt testing results are influenced by tilt protocol. Europace 2015; 18:1108-12. [DOI: 10.1093/europace/euv262] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 07/09/2015] [Indexed: 11/14/2022] Open
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Rangel I, Freitas J, Correia AS, Sousa A, Lebreiro A, de Sousa C, Maciel MJ, Azevedo E. The usefulness of the head-up tilt test in patients with suspected epilepsy. Seizure 2014; 23:367-70. [PMID: 24636722 DOI: 10.1016/j.seizure.2014.02.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2013] [Revised: 02/07/2014] [Accepted: 02/09/2014] [Indexed: 12/20/2022] Open
Abstract
PURPOSE It is estimated that approximately 20-30% of patients diagnosed with epilepsy have been misdiagnosed, and neurocardiogenic syncope (NCS) might frequently be the real cause of transient loss of consciousness (TLOC) episodes. We assessed the role of the head-up tilt test (HUTT) in patients previously diagnosed with refractory epilepsy to evaluate the ability of this test to correctly diagnose patients with NCS. METHOD We retrospectively analysed the clinical records of 107 consecutive patients with a previous diagnosis of refractory epilepsy that were taking antiepileptic drugs and who were referred for HUTT between January 2000 and December 2010. During the subsequent follow-up, we recorded the treatments performed and the recurrence of symptoms. RESULTS Complete follow-up data were available for 94 (88%) patients, and the mean follow-up period was 80±36 months. The HUTT was positive in 54% of patients. Thirty-one (33%) patients were misdiagnosed with epilepsy, and 20 (21%) patients had a dual diagnosis of NCS and epilepsy. The recurrence of TLOC was reported in 55% of the patients, but it was significantly lower in the misdiagnosed group (42% versus 64%; P=0.039). CONCLUSION NCS is an important cause of epilepsy misdiagnosis. The HUTT is often critical for making an accurate diagnosis and subsequently selecting the appropriate treatment for patients presenting with TLOC. The diagnostic overlap between epilepsy and NCS is not uncommon, suggesting that electroencephalographic monitoring during a HUTT may play an important role in diagnosing patients with recurrent, undiagnosed TLOC episodes.
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Affiliation(s)
- Inês Rangel
- Cardiology Department, São João Hospital Center, Porto, Portugal; Faculty of Medicine of Porto University, Porto, Portugal.
| | - João Freitas
- Cardiology Department, São João Hospital Center, Porto, Portugal; Faculty of Medicine of Porto University, Porto, Portugal
| | - Ana Sofia Correia
- Cardiology Department, São João Hospital Center, Porto, Portugal; Faculty of Medicine of Porto University, Porto, Portugal
| | - Alexandra Sousa
- Cardiology Department, São João Hospital Center, Porto, Portugal; Faculty of Medicine of Porto University, Porto, Portugal
| | - Ana Lebreiro
- Cardiology Department, São João Hospital Center, Porto, Portugal; Faculty of Medicine of Porto University, Porto, Portugal
| | - Carla de Sousa
- Cardiology Department, São João Hospital Center, Porto, Portugal; Faculty of Medicine of Porto University, Porto, Portugal
| | - Maria Júlia Maciel
- Cardiology Department, São João Hospital Center, Porto, Portugal; Faculty of Medicine of Porto University, Porto, Portugal
| | - Elsa Azevedo
- Neurology Department, São João Hospital Center, Porto, Portugal; Faculty of Medicine of Porto University, Porto, Portugal
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Solbiati M, Sheldon R. Syncope: how the EEG helps in understanding clinical findings. Brain 2014; 137:309-11. [DOI: 10.1093/brain/awt363] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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van Dijk JG, Thijs RD, van Zwet E, Tannemaat MR, van Niekerk J, Benditt DG, Wieling W. The semiology of tilt-induced reflex syncope in relation to electroencephalographic changes. Brain 2013; 137:576-85. [DOI: 10.1093/brain/awt332] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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28
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Broestl L, Cornes S, Dubal DB. Reversible Suppression of Electrocerebral Activity. Neurohospitalist 2013; 3:229-30. [DOI: 10.1177/1941874413485588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Lauren Broestl
- Department of Neurology, University of California, San Francisco, CA, USA
| | - Susannah Cornes
- Department of Neurology, University of California, San Francisco, CA, USA
| | - Dena B. Dubal
- Department of Neurology, University of California, San Francisco, CA, USA
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Bozorgi A, Chung S, Kaffashi F, Loparo KA, Sahoo S, Zhang GQ, Kaiboriboon K, Lhatoo SD. Significant postictal hypotension: expanding the spectrum of seizure-induced autonomic dysregulation. Epilepsia 2013; 54:e127-30. [PMID: 23758665 PMCID: PMC3769446 DOI: 10.1111/epi.12251] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/15/2013] [Indexed: 11/30/2022]
Abstract
Periictal autonomic dysregulation is best studied using a "polygraphic" approach: electroencephalography ([EEG]), 3-channel electrocardiography [ECG], pulse oximetry, respiration, and continuous noninvasive blood pressure [BP]), which may help elucidate agonal pathophysiologic mechanisms leading to sudden unexpected death in epilepsy (SUDEP). A number of autonomic phenomena have been described in generalized tonic-clonic seizures (GTCS), the most common seizure type associated with SUDEP, including decreased heart rate variability, cardiac arrhythmias, and changes in skin conductance. Postictal generalized EEG suppression (PGES) has been identified as a potential risk marker of SUDEP, and PGES has been found to correlate with post-GTCS autonomic dysregulation in some patients. Herein, we describe a patient with a GTCS in whom polygraphic measurements were obtained, including continuous noninvasive blood pressure recordings. Significant postictal hypotension lasting >60 s was found, which closely correlated with PGES duration. Similar EEG changes are well described in hypotensive patients with vasovagal syncope and a similar vasodepressor phenomenon, and consequent cerebral hypoperfusion may account for the PGES observed in some patients after a GTCS. This further raises the possibility that profound, prolonged, and irrecoverable hypotension may comprise one potential SUDEP mechanism.
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Affiliation(s)
- Alireza Bozorgi
- Epilepsy Center, Neurological Institute, University Hospitals Case Medical Center, Cleveland, Ohio 44106, USA
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So J, Shin WJ, Shim JH. A cardiovascular collapse occurred in the beach chair position for shoulder arthroscopy under general anesthesia -A case report-. Korean J Anesthesiol 2013; 64:265-7. [PMID: 23560195 PMCID: PMC3611079 DOI: 10.4097/kjae.2013.64.3.265] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Revised: 05/30/2012] [Accepted: 06/05/2012] [Indexed: 11/16/2022] Open
Abstract
The occurrence of severe hypotension and bradycardia, following placing to the beach chair position from supine during general anesthesia for repair of tendon injury of the rotator cuff of shoulder in a healthy 50 year-old man was described. The Bezold-Jarisch reflex, which is known to inhibit cardiovascular reflex and composed of three kinds of symptoms such as vasodilation, bradycardia and hypotension, has been reported mainly in peripheral nerve block, and may occur during orthostasis, hypovolemia, hemorrhage, supine inferior vena cava compression in pregnancy, interscalene block for shoulder surgery in the sitting position and so on. The bradycardia and hypotension can be more aggravated when causative elements overlaps each other. Anticholinergics and vasopressor were injected intravenously, and position of the patient was changed to the supine position immediately resulting in a normal vital signs dramatically.
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Affiliation(s)
- Jihyun So
- Department of Anesthesiology and Pain Medicine, College of Medicine, Hanyang University, Guri, Korea
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Sarrigiannis PG, Randall M, Kandler RH, Grunewald RA, Harkness K, Reuber M. Stretch syncope: reflex vasodepressor faints easily mistaken for epilepsy. Epilepsy Behav 2011; 20:450-3. [PMID: 21324752 DOI: 10.1016/j.yebeh.2010.12.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Accepted: 12/09/2010] [Indexed: 11/30/2022]
Abstract
The pathophysiology of stretch syncope is demonstrated through the clinical, electrophysiological, and hemodynamic findings in three patients. Fifty-seven attacks were captured by video/EEG monitoring. Simultaneous EEG, transcranial (middle cerebral artery) doppler, and continuous arterial pressure measurements were obtained for at least one typical attack of each patient. They all experienced a compulsion to precipitate their attacks. Episodes started with a stereotyped phase of stretching associated with neck torsion and breath holding, followed by a variable degree of loss of consciousness and asymmetric, recurrent facial and upper limb jerks in the more prolonged episodes. Significant sinus tachycardia coincided with the phase of stretching and was followed within 9-16 seconds by rhythmic generalized slow wave abnormalities on the EEG in attacks with impairment of consciousness. Transcranial doppler studies showed a dramatic drop in cerebral perfusion in the middle cerebral arteries during the episodes. The combination of the stereotyped semiology of the attacks, the pseudofocal myoclonic jerking, and the rhythmic generalized slow wave EEG abnormalities with the tachycardia make differential diagnosis from epilepsy challenging.
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Song PS, Kim JS, Park J, Yim HR, Huh J, Kim JH, On YK. Seizure-like activities during head-up tilt test-induced syncope. Yonsei Med J 2010; 51:77-81. [PMID: 20046517 PMCID: PMC2799981 DOI: 10.3349/ymj.2010.51.1.77] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Revised: 04/27/2009] [Accepted: 05/15/2009] [Indexed: 11/27/2022] Open
Abstract
PURPOSE Some patients with neurally mediated reflex syncope may be misdiagnosed as epilepsy because myoclonic jerky movements are observed during syncope. The seizure-like activities during the head-up tilt test (HUT) have been rarely reported. The purpose of this study was to assess the characteristics of these seizure-like activities and evaluate whether there are differences in the clinical characteristics and hemodynamic parameters of patients with neurally mediated reflex syncope with and without seizure-like activities during HUT-induced syncope. MATERIALS AND METHODS The medical records of 1,383 consecutive patients with a positive HUT were retrospectively reviewed, and 226 patients were included in this study. RESULTS Of 226 patients, 13 (5.75%) showed seizure-like activities, with 5 of these (2.21%) having multifocal myoclonic jerky movements, 5 (2.21%) having focal seizure-like activity involving one extremity, and 3 (1.33%) having upward deviation of eye ball. Comparison of patients with and without seizure-like activities revealed no significant differences in terms of clinical variables and hemodynamic parameters during HUT. CONCLUSION Seizure-like activities occurred occasionally during HUT-induced syncope in patients with neurally mediated reflex syncope. The seizure-like activities during HUT might not be related to the severity of the syncopal episodes or hemodynamic changes during HUT.
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Affiliation(s)
- Pil Sang Song
- Department of Medicine, Cardiac and Vascular Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - June Soo Kim
- Department of Medicine, Cardiac and Vascular Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Jungwae Park
- Department of Medicine, Cardiac and Vascular Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Hye Ran Yim
- Department of Medicine, Cardiac and Vascular Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - June Huh
- Department of Pediatrics, Cardiac and Vascular Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Jun Hyung Kim
- Department of Internal Medicine, Chungnam National University School of Medicine, Daejeon, Korea
| | - Young Keun On
- Department of Medicine, Cardiac and Vascular Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
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Martinez-Fernandez E, García FB, Gonzalez-Marcos JR, Peralta AG, Garcia AG, Deya AM. Clinical and electroencephalographic features of carotid sinus syncope induced by internal carotid artery angioplasty. AJNR Am J Neuroradiol 2008; 29:269-72. [PMID: 17974603 DOI: 10.3174/ajnr.a0823] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Carotid sinus syncope may occur acutely during internal carotid artery angioplasty (CA). We performed this study to investigate the clinical, electroencephalographic (EEG), and hemodynamic features of carotid sinus syncope induced by CA. MATERIALS AND METHODS Between 1992 and 2003, clinical, EEG, and cardiovascular monitoring was performed in 359 consecutive patients undergoing CA. RESULTS Carotid sinus reaction (CSR) and syncope occurred in 62.7% and 18.6% of the procedures, respectively. CSR and syncopal spells were classified into cardioinhibitory, vasodepressor, and mixed type. Syncope occurred more frequently in patients with cardioinhibitory CSR (P < .001). The odds ratios for the risk of syncope in patients with cardioinhibitory CSR and vasodepressor/mixed CSR were 6.9 and 1.4, respectively. Sixty-one patients had cardioinhibitory syncope; 7 had the vasodepressor/mixed type. Thirteen spells were not related to cardiovascular disturbances. This last syncope subtype was significantly associated with brain hemodynamic disturbances, including a decrease in cerebral vasoreactivity (P = .04) and the absence of function of both communicating arteries (P = .03). Convulsive movements resembling supplementary sensorimotor seizures occurred in 79% of patients who experienced syncopal spells. EEG changes were more prominent in patients with cardioinhibitory syncope. CONCLUSIONS Syncope occurs frequently in patients undergoing CA and can be misdiagnosed as seizures. The most frequent mechanism was a cardioinhibitory response. Cerebral hemodynamic disturbances may play a crucial role in the pathophysiology of syncope with normal sinus rhythm and normotension. Moreover, direct depression of the CNS following carotid sinus distension is likely to be involved.
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Affiliation(s)
- E Martinez-Fernandez
- Department of Neurology, Hospitales Universitarios Virgen del Rocio, Seville, Spain.
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Benedek K, Pálinkás A, Abrahám G, Beniczky S, Vécsei L, Rudas L. Pseudosyncope and pseudoseizure. Orv Hetil 2007; 148:1231-6. [PMID: 17588857 DOI: 10.1556/oh.2007.28001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A syncope gyakori kórkép, mely jelentős terheket ró az egészségügyre. Bár diagnosztikus eszközeink fejlődnek, az esetek egy kis hányadában az eszméletvesztés pontos oka az alapos kivizsgálás ellenére is rejtve marad. Az ismeretlen eredetű syncopék csoportjába tartozik a pszichogén álsyncope, mely – szemben a valódi syncopéval – nem jár az agyi keringés átmeneti zavarával. Az álsyncope valójában a konverziós betegség egyik megnyilvánulása, és mint ilyen, számos jellegzetességében osztozik az álgörcsrohammal. Az utóbbira ugyancsak jellemző, hogy a rohamok alatt hiányoznak a görcstevékenység jellegzetes neurológiai és EEG-manifesztációi. A két megjelenési forma esetenként ugyanazon betegben váltakozva léphet fel. Közleményünkben egy álsyncopékat és álgörcsrohamokat egyaránt produkáló beteg történetét mutatjuk be. Az eset kapcsán áttekintjük az álsyncope irodalmát, és felhívjuk a figyelmet az interdiszciplináris diagnosztikus megközelítés szerepére.
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Affiliation(s)
- Krisztina Benedek
- Szegedi Tudományegyetem, Szent-Györgyi Albert Orvos- és Gyógyszerésztudományi Centrum, Altalános Orvostudományi Kar Neurológiai Klinika, Szeged
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Fang SC, Chan HL, Chen WH. Approximate entropy analysis of electroencephalogram in vasovagal syncope on tilt table test. CONFERENCE PROCEEDINGS : ... ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL CONFERENCE 2007; 2006:590-2. [PMID: 17271745 DOI: 10.1109/iembs.2004.1403226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Thirty vasovagal attacks on sublingual nitroglycerin stressed tilting test were selected. By the method of shifting window along the continuous EEG signals the linear (spectral power and coherence) and nonlinear (approximate entropy) EEG features of the whole course in the tilt table test were demonstrated. Of all the EEG parameters approximate entropy is a more sensitive index in clarifying stages of various degree of tilting stress and in identifying the syncopal transient.
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Affiliation(s)
- S C Fang
- Dept. of Neurology, Shin-Kong WHS Memorial Hospital, Taipei, Taiwan
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Haubrich C, Kohnke A, Kloetzsch C, Moeller-Hartmann W, Diehl RR. Bilateral vertebral artery disease: transcranial Doppler assessment of the hemodynamic vulnerability to changes in posture. ULTRASOUND IN MEDICINE & BIOLOGY 2006; 32:1485-91. [PMID: 17045868 DOI: 10.1016/j.ultrasmedbio.2006.06.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2006] [Revised: 06/01/2006] [Accepted: 06/08/2006] [Indexed: 05/12/2023]
Abstract
Posture changes may cause hemodynamic ischemic events, particularly in severe vertebrobasilar artery disease. It may be difficult and not without risk to prove this vulnerability to changes in posture during angiography. Therefore, TCD monitoring with passive tilting (PT) was used to evaluate cerebral hemodynamics distally to severe bilateral vertebral artery disease (BVAD). PCA flow velocity changes and dynamic cerebral autoregulation (DCA) were analyzed in supine and upright position. Despite a significant autoregulatory deficit distally to BVAD, the posterior cerebral blood supply seemed to be sufficiently maintained as long as systemic blood pressure changes were within normal limits. Posterior cerebral flow velocities, however, were significantly diminished when PT detected a systemic hypotension in upright position. This study proves the feasibility to combine PT and TCD monitoring of the PCA in patients with BVAD. In vertebrobasilar artery disease, the examination of spontaneous and tilt-induced autoregulatory responses could support the evaluation of a risk for hemodynamic ischemia.
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Mecarelli O, Pulitano P, Vicenzini E, Vanacore N, Accornero N, De Marinis M. Observations on EEG patterns in neurally-mediated syncope: an inspective and quantitative study. Neurophysiol Clin 2004; 34:203-7. [PMID: 15639129 DOI: 10.1016/j.neucli.2004.09.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2004] [Accepted: 09/06/2004] [Indexed: 11/18/2022] Open
Abstract
We performed an observational EEG study in 43 patients with neurally-mediated syncope in basal condition and during hyperventilation (HV), and compared it with 32 healthy controls. On blind analysis at rest, EEG was classified as normal in 47% of patients (vs. 94% of controls, P < 0.001). More abundant and pronounced delta-theta activities and alpha slowing were found in patients than in control subjects on both visual inspection and quantitative spectral analysis. During prolonged HV, the EEG remained normal in 21% of patients only. Slow activities became more evident in patients than in control subjects, and intermittent rhythmic delta activity appeared in 40% of syncopal patients. These "pseudoparoxysmal" EEG changes differed from the common slowings induced by HV in adult subjects and were not observed in our control subjects. Moreover, these distinctive EEG changes, a common finding in syncopal patients, could not be confused with epileptiform activity of any kind. Further studies will clarify the pathophysiology of these EEG modifications.
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Affiliation(s)
- O Mecarelli
- Department of Neurological Sciences, La Sapienza University, Viale Regina Elena, 336, 00161 Rome, Italy.
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Szufladowicz E, Maniewski R, Kozluk E, Zbiec A, Nosek A, Walczak F. Near-infrared spectroscopy in evaluation of cerebral oxygenation during vasovagal syncope. Physiol Meas 2004; 25:823-36. [PMID: 15382824 DOI: 10.1088/0967-3334/25/4/004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Near-infrared spectroscopy (NIRS) offers a non-invasive, real-time monitoring of cerebral oxygenation. This method is based on the oxygenation and the light wavelength dependent absorption of near-infrared light by tissue chromophores, e.g. oxyhaemoglobin and deoxyhaemoglobin. The objective of the present study was the application of NIRS for evaluation of the brain function during vasovagal syncope (VVS). The VVS is a clinical syndrome affecting ca 3.5% of the population and for which the widely used diagnostic examination in this disease entity is the head-up tilt table test (HUT). In this study 69 patients with a history of VVS were examined using HUT. In 42 patients VVS was provoked. Results of the examination have shown that the changes in cerebral oxygenation measured by the NIRS technique are distinctly visible before the syncope. A gradual decrease of oxyhaemoglobin followed by its sudden drop was observed in all the VVS patients. Changes in the oxyhaemoglobin concentration measured by NIRS were observed on average 3.3 min before the syncope. They preceded the presyncope symptoms about 1.3 min (p < 0.005), the blood pressure and heart rate drop 2.2 min (p < 0.0001) and the arterial blood saturation 2.6 min (p < 0.00001).
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Affiliation(s)
- E Szufladowicz
- National Institute of Cardiology, Alpejska 42, 04-628 Warsaw, Poland
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Schondorf R, Stein R, Roberts R, Benoit J, Cupples W. Dynamic cerebral autoregulation is preserved in neurally mediated syncope. J Appl Physiol (1985) 2001; 91:2493-502. [PMID: 11717210 DOI: 10.1152/jappl.2001.91.6.2493] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To test whether cerebral autoregulation is impaired in patients with neurally mediated syncope (NMS), we evaluated 15 normal subjects and 37 patients with recurrent NMS. Blood pressure (BP), heart rate, and cerebral blood velocity (CBV) (transcranial Doppler) were recorded at rest and during 80 degrees head-up tilt (HUT). Static cerebral autoregulation as assessed from the change in cerebrovascular resistance during HUT was the same in NMS and controls. Properties of dynamic cerebral autoregulation were inferred from transfer gain, coherence, and phase of the relationship between BP and CBV estimated from filtered data segments (0.02-0.8 Hz). During the 3 min preceding syncope, dynamic cerebral autoregulation of subjects with NMS did not differ from that of controls nor did it change over the course of HUT in patients with NMS or in control subjects. Dynamic cerebral autoregulation was also unaffected by the degree of orthostatic intolerance as inferred from latency to onset of syncope. We conclude that cerebral autoregulation in patients with recurrent syncope does not differ from that of normal control subjects.
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Affiliation(s)
- R Schondorf
- Autonomic Reflex Laboratory, Department of Neurology, McGill University, Montreal, Quebec, Canada H3T 1E2.
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Abstract
Many of the primary symptoms of orthostatic intolerance (fatigue, diminished concentration) as well as some of the premonitory symptoms of neurally mediated syncope (NMS) are thought to be due to cerebral hypoperfusion. Transcranial Doppler measurements of middle cerebral artery blood velocity (CBV) is at present the only technique for assessing rapid changes in cerebral blood flow, and hence for evaluating dynamic cerebral autoregulation. However, controversies exist regarding data interpretation. At syncope, during the collapse of blood pressure (BP), diastolic CBV diminishes, whereas systolic CBV is maintained. Some consider this increase in CBV pulsatility to be indicative of a paradoxical increase in cerebrovascular resistance (CVR) prior to syncope. Others note that mean CBV decreases much less than does mean BP, implying that cerebral autoregulatory mechanisms are intact and functioning at syncope. Similarly, there is no evidence of impaired dynamic cerebral autoregulation, as measured by standard linear transfer-function analysis, in patients with NMS. Some patients with exaggerated postural tachycardia (POTS) have been found to have an excessive decrease in CBV during head-up tilt. Controversy exists as to whether this decrease results from an excessive sympathetic outflow to the cerebral vasculature or from hyperventilation. However, many other equally symptomatic patients with a similar hemodynamic profile of exaggerated tachycardia during head-up tilt have normal CBV changes during this maneuver and have normal dynamic cerebral autoregulation as determined by transfer-function analysis. Whether these discrepancies reflect different pathologies in patients with POTS is currently unknown.
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Affiliation(s)
- R Schondorf
- Autonomic Reflex Laboratory, Department of Neurology, McGill University, Sir Mortimer B. Davis Jewish General Hospital, Montreal, Quebec, Canada H3T 1E2.
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Ammirati F, Colivicchi F, Santini M. Effects of intravenous etilefrine in neurocardiogenic syncope induced by head-up tilt testing. Am J Cardiol 2000; 86:472-4. [PMID: 10946050 DOI: 10.1016/s0002-9149(00)00972-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- F Ammirati
- Heart Disease Department, S. Filippo Neri Hospital, Rome, Italy
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