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Daquin G, Bonini F. The landscape of drug resistant absence seizures in adolescents and adults: Pathophysiology, electroclinical spectrum and treatment options. Rev Neurol (Paris) 2024; 180:256-270. [PMID: 38413268 DOI: 10.1016/j.neurol.2023.11.010] [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: 10/02/2023] [Revised: 11/17/2023] [Accepted: 11/21/2023] [Indexed: 02/29/2024]
Abstract
The persistence of typical absence seizures (AS) in adolescence and adulthood may reduce the quality of life of patients with genetic generalized epilepsies (GGEs). The prevalence of drug resistant AS is probably underestimated in this patient population, and treatment options are relatively scarce. Similarly, atypical absence seizures in developmental and epileptic encephalopathies (DEEs) may be unrecognized, and often persist into adulthood despite improvement of more severe seizures. These two seemingly distant conditions, represented by typical AS in GGE and atypical AS in DEE, share at least partially overlapping pathophysiological and genetic mechanisms, which may be the target of drug and neurostimulation therapies. In addition, some patients with drug-resistant typical AS may present electroclinical features that lie in between the two extremes represented by these generalized forms of epilepsy.
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Affiliation(s)
- G Daquin
- Epileptology and Cerebral Rythmology, AP-HM, Timone hospital, Marseille, France
| | - F Bonini
- Epileptology and Cerebral Rythmology, AP-HM, Timone hospital, Marseille, France; Aix Marseille Univ, Inserm, INS, Inst Neurosci Syst, Marseille, France.
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El Youssef N, Marchi A, Bartolomei F, Bonini F, Lambert I. Sleep and epilepsy: A clinical and pathophysiological overview. Rev Neurol (Paris) 2023; 179:687-702. [PMID: 37598088 DOI: 10.1016/j.neurol.2023.07.006] [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: 07/14/2023] [Revised: 07/28/2023] [Accepted: 07/29/2023] [Indexed: 08/21/2023]
Abstract
The interaction between sleep and epilepsy is complex. A better understanding of the mechanisms linking sleep and epilepsy appears increasingly important as it may improve diagnosis and therapeutic strategies in patients with epilepsy. In this narrative review, we aim to (i) provide an overview of the physiological and pathophysiological processes linking sleep and epilepsy; (ii) present common sleep disorders in patients with epilepsy; (iii) discuss how sleep and sleep disorders should be considered in new therapeutic approaches to epilepsy such as neurostimulation; and (iv) present the overall nocturnal manifestations and differential diagnosis between epileptic seizures and parasomnia.
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Affiliation(s)
- N El Youssef
- AP-HM, Timone hospital, Sleep Unit, Epileptology and Cerebral Rhythmology, Marseille, France
| | - A Marchi
- AP-HM, Timone hospital, Sleep Unit, Epileptology and Cerebral Rhythmology, Marseille, France
| | - F Bartolomei
- AP-HM, Timone hospital, Sleep Unit, Epileptology and Cerebral Rhythmology, Marseille, France; Aix-Marseille University, Inserm, Inst Neurosci Syst (INS), Marseille, France
| | - F Bonini
- AP-HM, Timone hospital, Sleep Unit, Epileptology and Cerebral Rhythmology, Marseille, France; Aix-Marseille University, Inserm, Inst Neurosci Syst (INS), Marseille, France
| | - I Lambert
- AP-HM, Timone hospital, Sleep Unit, Epileptology and Cerebral Rhythmology, Marseille, France; Aix-Marseille University, Inserm, Inst Neurosci Syst (INS), Marseille, France.
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El Youssef N, Jegou A, Makhalova J, Naccache L, Bénar C, Bartolomei F. Consciousness alteration in focal epilepsy is related to loss of signal complexity and information processing. Sci Rep 2022; 12:22276. [PMID: 36566285 PMCID: PMC9789957 DOI: 10.1038/s41598-022-25861-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Accepted: 12/06/2022] [Indexed: 12/25/2022] Open
Abstract
Alteration of awareness is a main feature of focal epileptic seizures. In this work, we studied how the information contained in EEG signals was modified during temporal lobe seizures with altered awareness by using permutation entropy (PE) as a measure of the complexity of the signal. PE estimation was performed in thirty-six seizures of sixteen patients with temporal lobe epilepsy who underwent SEEG recordings. We tested whether altered awareness (based on the Consciousness Seizure Score) was correlated with a loss of signal complexity. We estimated global changes in PE as well as regional changes to gain insight into the mechanisms associated with awareness impairment. Our results reveal a positive correlation between the decrease of entropy and the consciousness score as well as the existence of a threshold on entropy that could discriminate seizures with no alteration of awareness from seizures with profound alteration of awareness. The loss of signal complexity was diffuse, extending bilaterally and to the associative cortices, in patients with profound alteration of awareness and limited to the temporal mesial structures in patients with no alteration of awareness. Thus PE is a promising tool to discriminate between the different subgroups of awareness alteration in TLE.
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Affiliation(s)
- Nada El Youssef
- grid.411266.60000 0001 0404 1115APHM, Timone Hospital, Epileptology and Cerebral Rhythmology, Marseille, France
| | - Aude Jegou
- grid.5399.60000 0001 2176 4817Aix Marseille Univ, INSERM, INS, Inst Neurosci Syst, Marseille, France
| | - Julia Makhalova
- grid.411266.60000 0001 0404 1115APHM, Timone Hospital, Epileptology and Cerebral Rhythmology, Marseille, France ,grid.411266.60000 0001 0404 1115APHM, Timone Hospital, CEMEREM, Marseille, France
| | - Lionel Naccache
- grid.50550.350000 0001 2175 4109APHP, Departments of Neurology & Clinical Neurophysiology Pitié Salpêtrière Hospital, Paris, France
| | - Christian Bénar
- grid.5399.60000 0001 2176 4817Aix Marseille Univ, INSERM, INS, Inst Neurosci Syst, Marseille, France
| | - Fabrice Bartolomei
- grid.411266.60000 0001 0404 1115APHM, Timone Hospital, Epileptology and Cerebral Rhythmology, Marseille, France ,grid.5399.60000 0001 2176 4817Aix Marseille Univ, INSERM, INS, Inst Neurosci Syst, Marseille, France ,grid.411266.60000 0001 0404 1115Service d’Epileptologie et de Rythmologie Cérébrale, Hôpital Timone, 264 Rue Saint-Pierre, 13005 Marseille, France
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Focal seizures producing loss of wakefulness without ictal asystole: Does temporal lobe syncope exist? Epilepsy Res 2022; 186:107015. [DOI: 10.1016/j.eplepsyres.2022.107015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 08/14/2022] [Accepted: 08/27/2022] [Indexed: 11/19/2022]
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Pruvost-Robieux E, Marchi A, Martinelli I, Bouchereau E, Gavaret M. Evoked and Event-Related Potentials as Biomarkers of Consciousness State and Recovery. J Clin Neurophysiol 2022; 39:22-31. [PMID: 34474424 PMCID: PMC8715993 DOI: 10.1097/wnp.0000000000000762] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
SUMMARY The definition of consciousness has been the subject of great interest for many scientists and philosophers. To better understand how evoked potentials may be identified as biomarkers of consciousness and recovery, the different theoretical models sustaining neural correlates of consciousness are reviewed. A multimodal approach can help to better predict clinical outcome in patients presenting with disorders of consciousness. Evoked potentials are inexpensive and easy-to-implement bedside examination techniques. Evoked potentials are an integral part of prognostic evaluation, particularly in cases of cognitive motor dissociation. Prognostic criteria are well established in postanoxic disorders of consciousness, especially postcardiac arrest but are less well determined in other etiologies. In the early examination, bilateral absence of N20 in disorder of consciousness patients is strongly associated with unfavorable outcome (i.e., death or unresponsive wakefulness syndrome) especially in postanoxic etiologies. This predictive value is lower in other etiologies and probably also in children. Both N20 and mismatch negativity are proven outcome predictors for acute coma. Many studies have shown that mismatch negativity and P3a are characterized by a high prognostic value for awakening, but some patients presenting unresponsive wakefulness syndrome also process a P3a. The presence of long-latency event-related potential components in response to stimuli is indicative of a better recovery. All neurophysiological data must be integrated within a multimodal approach combining repeated clinical evaluation, neuroimaging, functional imaging, biology, and neurophysiology combining passive and active paradigms.
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Affiliation(s)
- Estelle Pruvost-Robieux
- Neurophysiology Department, GHU Paris Psychiatry & Neurosciences, Sainte Anne, Paris, France
- Paris University, Paris, France
| | - Angela Marchi
- Neurophysiology Department, GHU Paris Psychiatry & Neurosciences, Sainte Anne, Paris, France
| | - Ilaria Martinelli
- Department of Neurosciences, St. Agostino-Estense Hospital, Azienda Ospedaliero, Universitaria di Modena, Modena, Italy;
| | - Eléonore Bouchereau
- Department of Anesthesiology and intensive care, GHU Paris Psychiatry & Neurosciences, Sainte Anne, Paris, France; and
| | - Martine Gavaret
- Neurophysiology Department, GHU Paris Psychiatry & Neurosciences, Sainte Anne, Paris, France
- Paris University, Paris, France
- INSERM UMR 1266, Paris, France
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Abstract
Impaired consciousness during seizures severely affects quality of life for people with
epilepsy but the mechanisms are just beginning to be understood. Consciousness is thought
to involve large-scale brain networks, so it is puzzling that focal seizures often impair
consciousness. Recent work investigating focal temporal lobe or limbic seizures in human
patients and experimental animal models suggests that impaired consciousness is caused by
active inhibition of subcortical arousal mechanisms. Focal limbic seizures exhibit
decreased neuronal firing in brainstem, basal forebrain, and thalamic arousal networks,
and cortical arousal can be restored when subcortical arousal circuits are stimulated
during seizures. These findings open the possibility of restoring arousal and
consciousness therapeutically during and following seizures by thalamic neurostimulation.
When seizures cannot be stopped by existing treatments, targeted subcortical stimulation
may improve arousal and consciousness, leading to improved safety and better psychosocial
function for people with epilepsy.
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Affiliation(s)
- Hal Blumenfeld
- Departments of Neurology, Neuroscience, Neurosurgery, Yale University School of Medicine, New Haven, CT, USA
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Impaired awareness in mesial temporal lobe epilepsy: Network analysis of foramen ovale and scalp EEG. Clin Neurophysiol 2021; 132:3084-3094. [PMID: 34717226 DOI: 10.1016/j.clinph.2021.09.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 08/11/2021] [Accepted: 09/01/2021] [Indexed: 11/22/2022]
Abstract
OBJECTIVE We use co-registration of foramen-ovale and scalp-EEG to investigate network alterations in temporal-lobe epilepsy during focal seizures without (aura) or with impairment of awareness (SIA). METHODS One aura and one SIA were selected from six patients. Temporal dynamic among 4 epochs, as well as the differences between aura and SIA, were analyzed through partial directed coherence and graph theory-based indices of centrality. RESULTS Regarding the auras temporal evolution, fronto-parietal (FP) regions showed decreased connectivity with respect to the interictal period, in both epileptogenic (EH) and non-epileptogenic hemisphere (nEH). During SIAs, temporal dynamic showed more changes than auras: centrality of mesial temporal (mT) regions changes during all conditions, and nEH FP centrality showed the same dynamic trend of the aura (decreased centrality), until the last epoch, close to the impaired awareness, when showed increased centrality. Comparing SIA with aura, in proximity of impaired awareness, increased centrality was found in all the regions, except in nEH mT. CONCLUSIONS Our findings suggested that the impairment of awareness is related to network alterations occurring first in neocortical regions and when awareness is still retained. SIGNIFICANCE The analysis of 'hub' alteration can represent a suitable biomarker for scalp EEG-based prediction of awareness impairment.
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Dheer P, Pati S, Chowdhury KK, Majumdar KK. Enhanced gamma band mutual information is associated with impaired consciousness during temporal lobe seizures. Heliyon 2021; 6:e05769. [PMID: 33409386 PMCID: PMC7773881 DOI: 10.1016/j.heliyon.2020.e05769] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 07/24/2020] [Accepted: 12/14/2020] [Indexed: 11/24/2022] Open
Abstract
Background Epileptic seizures are characterized by aberrant synchronization. We hypothesized that higher synchronization across the seizure onset zone (SOZ) channels during a temporal lobe seizure contributes to impaired consciousness. New method All symmetric bivariate synchronization measures were extended to multivariate measure by a principal component analysis (PCA) based technique. A novel nonparametric method has been proposed to test the statistical significance between increased synchronization across the seizure onset zone (SOZ) channels and reduced consciousness. Results Increased synchronization in the gamma band towards seizure termination significantly contributes to impaired consciousness (p < 0.1). Synchronization reaches its peak in the extratemporal region (frontal lobe) ahead of the temporal region (p < 0.05). Synchronization is prominent in beta and gamma bands by most methods and it is more in the second half of seizure duration than in the first (p < 0.05). Conclusions Mutual information is the only synchronization measure out of the six that we studied, whose increase can be associated with the loss of consciousness in a statistically significant way.
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Affiliation(s)
- Puneet Dheer
- Systems Science and Informatics Unit, Indian Statistical Institute, 8th Mile, Mysore Road, Bangalore, India, 560059
| | - Sandipan Pati
- UAB Epilepsy Center, Department of Neurology, University of Alabama at Birmingham, CIRC 312, 1719 6th Avenue South, Birmingham, AL, 35294, USA
| | - Kalyan Kumar Chowdhury
- Statistical Quality Control Unit, Indian Statistical Institute, 8th Mile, Mysore Road, Bangalore, 560059, India
| | - Kaushik Kumar Majumdar
- Systems Science and Informatics Unit, Indian Statistical Institute, 8th Mile, Mysore Road, Bangalore, India, 560059
- Corresponding author.
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Northoff G, Lamme V. Neural signs and mechanisms of consciousness: Is there a potential convergence of theories of consciousness in sight? Neurosci Biobehav Rev 2020; 118:568-587. [PMID: 32783969 DOI: 10.1016/j.neubiorev.2020.07.019] [Citation(s) in RCA: 81] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 07/03/2020] [Accepted: 07/16/2020] [Indexed: 11/18/2022]
Abstract
Various theories for the neural basis of consciousness have been proposed, suggesting a diversity of neural signs and mechanisms. We ask to what extent this diversity is real, or whether many theories share the same basic ideas with a potential for convergence towards a more unified theory of the neural basis of consciousness. For that purpose, we review and compare the various neural signs, measures, and mechanisms proposed in the different theories. We demonstrate that different theories focus on neural signs and measures of distinct aspects of neural activity including stimulus-related, prestimulus, and resting state activity as well as on distinct features of consciousness. Therefore, the various mechanisms proposed in the different theories may, in part, complement each other. Together, we provide insight into the shared basis and convergences (and, in part, discrepancies) of the different theories of consciousness. We conclude that the different theories concern distinct aspects of both neural activity and consciousness which, as we suppose, may be integrated and nested within the brain's overall temporo-spatial dynamics.
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Affiliation(s)
- Georg Northoff
- Mental Health Center, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China; Mind, Brain Imaging and Neuroethics, Institute of Mental Health Research, University of Ottawa, Ottawa, Canada; Centre for Research Ethics & Bioethics, University of Uppsala, Uppsala, Sweden.
| | - Victor Lamme
- Amsterdam Brain and Cognition (ABC), Department of Psychology, University of Amsterdam, the Netherlands
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