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Marinelli I, Walker JJ, Seneviratne U, D’Souza W, Cook MJ, Anderson C, Bagshaw AP, Lightman SL, Woldman W, Terry JR. Circadian distribution of epileptiform discharges in epilepsy: Candidate mechanisms of variability. PLoS Comput Biol 2023; 19:e1010508. [PMID: 37797040 PMCID: PMC10581478 DOI: 10.1371/journal.pcbi.1010508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 10/17/2023] [Accepted: 09/10/2023] [Indexed: 10/07/2023] Open
Abstract
Epilepsy is a serious neurological disorder characterised by a tendency to have recurrent, spontaneous, seizures. Classically, seizures are assumed to occur at random. However, recent research has uncovered underlying rhythms both in seizures and in key signatures of epilepsy-so-called interictal epileptiform activity-with timescales that vary from hours and days through to months. Understanding the physiological mechanisms that determine these rhythmic patterns of epileptiform discharges remains an open question. Many people with epilepsy identify precipitants of their seizures, the most common of which include stress, sleep deprivation and fatigue. To quantify the impact of these physiological factors, we analysed 24-hour EEG recordings from a cohort of 107 people with idiopathic generalized epilepsy. We found two subgroups with distinct distributions of epileptiform discharges: one with highest incidence during sleep and the other during day-time. We interrogated these data using a mathematical model that describes the transitions between background and epileptiform activity in large-scale brain networks. This model was extended to include a time-dependent forcing term, where the excitability of nodes within the network could be modulated by other factors. We calibrated this forcing term using independently-collected human cortisol (the primary stress-responsive hormone characterised by circadian and ultradian patterns of secretion) data and sleep-staged EEG from healthy human participants. We found that either the dynamics of cortisol or sleep stage transition, or a combination of both, could explain most of the observed distributions of epileptiform discharges. Our findings provide conceptual evidence for the existence of underlying physiological drivers of rhythms of epileptiform discharges. These findings should motivate future research to explore these mechanisms in carefully designed experiments using animal models or people with epilepsy.
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Affiliation(s)
- Isabella Marinelli
- Centre for Systems Modelling and Quantitative Biomedicine, University of Birmingham, Birmingham, United Kingdom
| | - Jamie J. Walker
- EPSRC Centre for Predictive Modelling in Healthcare, University of Exeter, Exeter, United Kingdom
| | - Udaya Seneviratne
- Department of Neurosciences, Monash Health, Clayton, Australia
- Department of Neuroscience, St. Vincent’s Hospital, University of Melbourne, Melbourne, Australia
| | - Wendyl D’Souza
- Department of Medicine, St. Vincent’s Hospital, University of Melbourne, Melbourne, Australia
| | - Mark J. Cook
- Department of Neuroscience, St. Vincent’s Hospital, University of Melbourne, Melbourne, Australia
| | - Clare Anderson
- School of Psychological Sciences and Turner Institute for Brain and Mental Health, Monash University, Clayton, Australia
- Centre for Human Brain Health, University of Birmingham, Birmingham, United Kingdom
| | - Andrew P. Bagshaw
- Centre for Human Brain Health, University of Birmingham, Birmingham, United Kingdom
| | - Stafford L. Lightman
- Bristol Medical School: Translational Health Sciences, University of Bristol, Bristol, United Kingdom
| | - Wessel Woldman
- Centre for Systems Modelling and Quantitative Biomedicine, University of Birmingham, Birmingham, United Kingdom
| | - John R. Terry
- Centre for Systems Modelling and Quantitative Biomedicine, University of Birmingham, Birmingham, United Kingdom
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Sekimoto M, Kato M, Muramatsu R, Onuma T. Cognitive dysfunction in drug-naïve late-onset temporal lobe epilepsy. Epilepsy Behav 2023; 146:109356. [PMID: 37499577 DOI: 10.1016/j.yebeh.2023.109356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Revised: 07/02/2023] [Accepted: 07/07/2023] [Indexed: 07/29/2023]
Abstract
OBJECTIVES To evaluate cognitive functions including memory in middle-aged and elderly patients with antiseizure drug-naïve late-onset temporal lobe epilepsy (TLE). METHODS We performed assessments with the Wechsler Adult Intelligence Scale-III (WAIS-III) and Wechsler Memory Scale-Revised (WMS-R) in 26 antiseizure drug-naïve patients with late-onset TLE, in comparison to 30 healthy subjects. We investigated the relationships between these cognitive function scores and clinical characteristics, seizure frequency, and frequency of interictal epileptic discharges (IEDs). RESULTS Patients with epilepsy had a significantly lower score than healthy controls in the verbal intelligence quotient (IQ), the performance IQ, and full-scale IQ in intelligence testing. Patients showed significantly decrease in the verbal memory scores, visual memory scores, general memory scores, and delayed recall scores compared with those in the control subjects. Delayed recall scores were significantly negatively correlated with recent seizure frequency and the total IEDs count per minute, but not with age of onset or duration of illness. SIGNIFICANCE Patients with antiseizure drug-naïve late-onset TLE displayed cognitive deficits including the domains of memory by using standard clinical neuropsychological test. Patients with late-onset epilepsy need to be considered for cognitive dysfunction at the time of diagnosis of TLE because they may have their daily life and work affected not only by epileptic seizures but also by cognitive deficits. Appearance of seizures and EEG abnormalities may affect the memory function in patients with late-onset TLE.
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Nair KP, Salaka RJ, Srikumar BN, Kutty BM, Rao BSS. Enriched environment rescues impaired sleep-wake architecture and abnormal neural dynamics in chronic epileptic rats. Neuroscience 2022; 495:97-114. [DOI: 10.1016/j.neuroscience.2022.05.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Revised: 05/12/2022] [Accepted: 05/19/2022] [Indexed: 11/16/2022]
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Giacomini T, Luria G, D’Amario V, Croci C, Cataldi M, Piai M, Nobile G, Bruni O, Consales A, Mancardi MM, Nobili L. On the role of REM sleep microstructure in suppressing interictal spikes in Electrical Status Epilepticus during Sleep. Clin Neurophysiol 2022; 136:62-68. [DOI: 10.1016/j.clinph.2022.01.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 01/04/2022] [Accepted: 01/07/2022] [Indexed: 11/26/2022]
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Pellegrino G, Hedrich T, Sziklas V, Lina JM, Grova C, Kobayashi E. How cerebral cortex protects itself from interictal spikes: The alpha/beta inhibition mechanism. Hum Brain Mapp 2021; 42:3352-3365. [PMID: 34002916 PMCID: PMC8249896 DOI: 10.1002/hbm.25422] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 03/05/2021] [Indexed: 11/10/2022] Open
Abstract
Interactions between interictal epileptiform discharges (IEDs) and distant cortical regions subserve potential effects on cognition of patients with focal epilepsy. We hypothesize that "healthy" brain areas at a distance from the epileptic focus may respond to the interference of IEDs by generating inhibitory alpha and beta oscillations. We predict that more prominent alpha-beta oscillations can be found in patients with less impaired neurocognitive profile. We performed a source imaging magnetoencephalography study, including 41 focal epilepsy patients: 21 with frontal lobe epilepsy (FLE) and 20 with mesial temporal lobe epilepsy. We investigated the effect of anterior (i.e., frontal and temporal) IEDs on the oscillatory pattern over posterior head regions. We compared cortical oscillations (5-80 Hz) temporally linked to 3,749 IEDs (1,945 frontal and 1,803 temporal) versus an equal number of IED-free segments. We correlated results from IED triggered oscillations to global neurocognitive performance. Only frontal IEDs triggered alpha-beta oscillations over posterior head regions. IEDs with higher amplitude triggered alpha-beta oscillations of higher magnitude. The intensity of posterior head region alpha-beta oscillations significantly correlated with a better neuropsychological profile. Our study demonstrated that cerebral cortex protects itself from IEDs with generation of inhibitory alpha-beta oscillations at distant cortical regions. The association of more prominent oscillations with a better cognitive status suggests that this mechanism might play a role in determining the cognitive resilience in patients with FLE.
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Affiliation(s)
- Giovanni Pellegrino
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Tanguy Hedrich
- Department of Biomedical Engineering, Multimodal Functional Imaging Lab, McGill University, Montreal, Quebec, Canada
| | - Viviane Sziklas
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Jean-Marc Lina
- Departement de Genie Electrique, Ecole de Technologie Superieure, Montreal, Quebec, Canada.,Centre De Recherches En Mathematiques, Montreal, Quebec, Canada
| | - Christophe Grova
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada.,Department of Biomedical Engineering, Multimodal Functional Imaging Lab, McGill University, Montreal, Quebec, Canada.,Centre De Recherches En Mathematiques, Montreal, Quebec, Canada.,Department of Physics and PERFORM Centre, Concordia University, Montreal, Quebec, Canada
| | - Eliane Kobayashi
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
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Goyal M, Mishra P, Jaseja H. Significance of rapid eye movement sleep in the comorbidity of obstructive sleep apnea and epilepsy. Med Hypotheses 2020; 144:109949. [PMID: 32534338 DOI: 10.1016/j.mehy.2020.109949] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Accepted: 06/02/2020] [Indexed: 02/08/2023]
Affiliation(s)
- Manish Goyal
- Department of Physiology, AIIMS Bhubaneswar, Odisha, India.
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Yuan X, Sun M. The value of rapid eye movement sleep in the localization of epileptogenic foci for patients with focal epilepsy. Seizure 2020; 81:192-197. [PMID: 32854037 DOI: 10.1016/j.seizure.2020.06.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 05/06/2020] [Accepted: 06/04/2020] [Indexed: 11/26/2022] Open
Abstract
PURPOSE Our aim was to investigate the value of rapid eye movement (REM) during prolonged scalp video-electroencephalography (VEEG) in the localization of epileptogenic foci for patients with focal epilepsy. METHOD We retrospectively studied a total of 59 patients with focal epilepsy and 31 of 59 received surgery. We assessed localization of interictal epileptiform discharges (IEDs) during REM, non-rapid eye movement sleep (NREM) and wakefulness to compare with the localization of ictal EEG, clinical semiology, magnetic resonance imaging (MRI) and positron emission tomography (PET) and stereo-electroencephalogram (SEEG). We graded postoperative follow-up outcome according to Engel criteria to further verify the accuracy of localization of epileptogenic foci in REM-IEDs. NREM-IEDs and Wakefulness-IEDs. Stepwise multiple logistic regression was carried out to assess for independent association of good prognosis with REM accurate localization, temporal lobe epilepsy and MRI accurate localization. RESULTS Clinical semiology was concordant to REM-IEDs in 40 patients (72.7 %), NREM-IEDs in 27 (49.1 %), and Wakefulness-IEDs in 25 (45.5 %). MRI lesion was concordant with REM-IEDs in 35 patients (81.4 %), Wakefulness-IEDs in 26 (60.5 %), and NREM-IEDs in 25 (58.1 %). PET localization was concordant with REM-IEDs in 20 patients (76.9 %), Wakefulness-IEDs and NREM-IEDs in 11 (42.3 %). SEEG localization was concordant with REM-IEDs in 15 patients (65.2 %), Wakefulness-IEDs in 10 (43.5 %), and NREM-IEDs in 8 (34.8 %). Thirty-one patients received surgery, and 30 (96.8 %) of them achieved good seizure control (Engel I-III). The surgical site was concordant with REM-IEDs in 23 (74.2 %), Wakefulness-IEDs and NREM-IEDs in 14 (45.2 %). In addition, the accuracy of REM-IEDs localization in temporal epilepsy (90 %) was higher than that extra-temporal epilepsy (45.5 %). REM accurate localization of epileptogenic foci was an independent factor contributing to good prognosis (P = 0.025, OR = 12.368). CONCLUSIONS Compared with NREM-IEDs and Wakefulness-IEDs, REM-IEDs had most value for localization of epileptogenic foci in patients with focal epilepsy. REM-IEDs- accurate localization of epileptogenic foci was an independent factor contributing to good prognosis for postsurgical patients with focal epilepsy.
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Affiliation(s)
- Xiao Yuan
- Shanxi Medical University, Taiyuan City, Shanxi Province, 030001, China
| | - Meizhen Sun
- The First Hospital of Shanxi Medical University, Taiyuan City, Shanxi Province, 030001, China.
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Şanlıdağ B, Köken ÖY, Temel EÜ, Arhan E, Aydın K, Serdaroğlu A. Benign epilepsy with centrotemporal spikes: Is there a thalamocortical network dysfunction present? Seizure 2020; 79:44-48. [PMID: 32416566 DOI: 10.1016/j.seizure.2020.04.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 04/10/2020] [Accepted: 04/12/2020] [Indexed: 10/24/2022] Open
Abstract
INTRODUCTION Benign epilepsy of childhood with centrotemporal spikes (BECTS) is one of the most frequently seen epileptic syndromes in childhood. It is characterized by centrotemporal spikes (CTS) on electroencephalography (EEG) that are typically activated by drowsiness and stage N2 sleep. The location, frequency, and amplitude of the spikes may vary in different EEG records of the same patient, supporting the presence of a global pathology rather than a focal one. Despite the well-known relation between BECTS and stage N2 sleep, the results of sleep studies have been diverse and have mainly focused on sleep cycles. The characteristics of sleep spindles in the interictal periods have not been studied well. METHODS A retrospective study involving patients with BECTS who were admitted to the Gazi University, Faculty of Medicine, Department of Pediatric Neurology from January 2017 to October 2018 was conducted herein. Patients with BECTS and age-matched controls who had stage N2 sleep records of 10 min were enrolled for spindle amplitude (peak-to-peak difference in spindle voltage), frequency (number of waveforms per second), and duration and density (number of spindle bursts/minute of stage N2 sleep). RESULTS A total of 30 children with BECTS and 20 age-matched healthy peers were enrolled in the study. There were no significant differences between the age and sex of the patients. Statistically significant lower mean values of the amplitude, and duration and density of the spindle activity were observed in patients with BECTS when compared to the controls (P: 0.034, P: 0.016, and 0.020, respectively). Additionally, the risk of epilepsy was found to increase by 1.9 %, by the decrease of the mean amplitude of the spindles by 1 mV when compared to control group. CONCLUSION The interictal records of stage N2 sleep differed in the patients with BECTS when compared to the controls. Findings related to the stage N2 sleep of the present study may suggest a network problem involving the thalamus and thalamocortical pathways in patients with BECTS.
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Affiliation(s)
- Burçin Şanlıdağ
- Department of Pediatric Neurology, Medical Faculty of Near East University, Nicosia, Cyprus.
| | - Özlem Yayıcı Köken
- Department of Pediatric Neurology, SBU, Dr. Sami Ulus Research and Training Hospital, Ankara, Turkey.
| | - Esra Ülgen Temel
- Department of Pediatric Neurology, Medical Faculty of Gazi University, Ankara, Turkey.
| | - Ebru Arhan
- Department of Pediatric Neurology, Medical Faculty of Gazi University, Ankara, Turkey.
| | - Kürşad Aydın
- Department of Pediatric Neurology, Medical Faculty of Medipol University, İstanbul, Turkey.
| | - Ayşe Serdaroğlu
- Department of Pediatric Neurology, Medical Faculty of Gazi University, Ankara, Turkey.
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Broutian A, Belyakova-Bodina A, Dolgova S, Pushkar T, Abramova A. Interictal epileptiform activity in sleep and wakefulness in patients with temporal lobe epilepsy. BULLETIN OF RUSSIAN STATE MEDICAL UNIVERSITY 2019. [DOI: 10.24075/brsmu.2019.073] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sleep is an important activator of epileptiform activity, with epileptiform discharge (ED) probability varying among sleep stages. The aim of our study was to analyze the association between epileptiform activity and sleep stages or wakefulness in adults with temporal discharges. We analyzed 32 long-term overnight EEG recordings. All focal discharges were marked, and the entire sleep was staged. Absolute general epileptiform discharge index (EDI), defined as a ratio of total ED number to the full recording time in hours, as well as absolute EDIs for REM, N1, N2 and N3 stages were calculated. The majority of patients (28) had the highest EDI in N3. EDI increased significantly while sleep progressed to deeper stages, reaching its peak in N3. In REM sleep, EDI sharply declined (p < 0.01) reaching the levels of wakefulness. Increasing synchronization of cortical neurons is thought to be the major mechanism of EDI rise in NREM sleep. Hence, N3 seems to be the most sensitive stage to capture EDs, which highlights the importance of deep sleep recording in patients with temporal epilepsy.
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Coelli S, Maggioni E, Rubino A, Campana C, Nobili L, Bianchi AM. Multiscale Functional Clustering Reveals Frequency Dependent Brain Organization in Type II Focal Cortical Dysplasia With Sleep Hypermotor Epilepsy. IEEE Trans Biomed Eng 2019; 66:2831-2839. [PMID: 30716026 DOI: 10.1109/tbme.2019.2896893] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVE A multiscale functional clustering approach is proposed to investigate the organization of the epileptic networks during different sleep stages and in relation with the occurrence of seizures. METHOD Stereo-electroencephalographic signals from seven pharmaco-resistant epileptic patients (focal cortical dysplasia type II) were analyzed. The discrete wavelet transform provided a multiscale framework on which a data-driven functional clustering procedure was applied, based on multivariate measures of integration and mutual information. The most interacting functional clusters (FCs) within the sampled brain areas were extracted. RESULTS FCs characterized by strongly integrated activity were observed mostly in the beta and alpha frequency bands, immediately before seizure onset and in deep sleep stages. These FCs generally included the electrodes from the epileptogenic zone. Furthermore, repeatable patterns were found across ictal events in the same patient. CONCLUSION In line with previous studies, our findings provide evidence of the important role of beta and alpha activity in seizures generation and support the relation between epileptic activity and sleep stages. SIGNIFICANCE Despite the small number of subjects included in the study, the present results suggest that the proposed multiscale functional clustering approach is a useful tool for the identification of the frequency-dependent mechanisms underlying seizure generation.
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Giuliano L, Uccello D, Fatuzzo D, Mainieri G, Zappia M, Sofia V. Electroclinical findings of minor motor events during sleep in temporal lobe epilepsy. Epilepsia 2017; 58:1261-1267. [DOI: 10.1111/epi.13770] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/26/2017] [Indexed: 01/18/2023]
Affiliation(s)
- Loretta Giuliano
- Department of Medical and Surgical Sciences and Advanced Technologies “G.F. Ingrassia”; University of Catania; Catania Italy
| | - Denise Uccello
- Department of Medical and Surgical Sciences and Advanced Technologies “G.F. Ingrassia”; University of Catania; Catania Italy
| | - Daniela Fatuzzo
- Department of Medical and Surgical Sciences and Advanced Technologies “G.F. Ingrassia”; University of Catania; Catania Italy
| | - Greta Mainieri
- Department of Medical and Surgical Sciences and Advanced Technologies “G.F. Ingrassia”; University of Catania; Catania Italy
| | - Mario Zappia
- Department of Medical and Surgical Sciences and Advanced Technologies “G.F. Ingrassia”; University of Catania; Catania Italy
| | - Vito Sofia
- Department of Medical and Surgical Sciences and Advanced Technologies “G.F. Ingrassia”; University of Catania; Catania Italy
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Frauscher B, von Ellenrieder N, Dubeau F, Gotman J. EEG desynchronization during phasic REM sleep suppresses interictal epileptic activity in humans. Epilepsia 2016; 57:879-88. [PMID: 27112123 PMCID: PMC4949560 DOI: 10.1111/epi.13389] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/21/2016] [Indexed: 01/25/2023]
Abstract
Objective Rapid eye movement (REM) sleep has a suppressing effect on epileptic activity. This effect might be directly related to neuronal desynchronization mediated by cholinergic neurotransmission. We investigated whether interictal epileptiform discharges (IEDs) and high frequency oscillations—a biomarker of the epileptogenic zone—are evenly distributed across phasic and tonic REM sleep. We hypothesized that IEDs are more suppressed during phasic REM sleep because of additional cholinergic drive. Methods Twelve patients underwent polysomnography during long‐term combined scalp‐intracerebral electroencephalography (EEG) recording. After sleep staging in the scalp EEG, we identified segments of REM sleep with rapid eye movements (phasic REM) and segments of REM sleep without rapid eye movements (tonic REM). In the intracerebral EEG, we computed the power in frequencies <30 Hz and from 30 to 500 Hz, and marked IEDs, ripples (>80 Hz) and fast ripples (>250 Hz). We grouped the intracerebral channels into channels in the seizure‐onset zone (SOZ), the exclusively irritative zone (EIZ), and the normal zone (NoZ). Results Power in frequencies <30 Hz was lower during phasic than tonic REM sleep (p < 0.001), most likely reflecting increased desynchronization. IEDs, ripples and fast ripples, were less frequent during phasic than tonic REM sleep (phasic REM sleep: 39% of spikes, 35% of ripples, 18% of fast ripples, tonic REM sleep: 61% of spikes, 65% of ripples, 82% of fast ripples; p < 0.001). In contrast to ripples in the epileptogenic zone, physiologic ripples were more abundant during phasic REM sleep (phasic REM sleep: 73% in NoZ, 30% in EIZ, 28% in SOZ, tonic REM sleep: 27% in NoZ, 70% in EIZ, 72% in SOZ; p < 0.001). Significance Phasic REM sleep has an enhanced suppressive effect on IEDs, corroborating the role of EEG desynchronization in the suppression of interictal epileptic activity. In contrast, physiologic ripples were increased during phasic REM sleep, possibly reflecting REM‐related memory consolidation and dreaming.
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Affiliation(s)
- Birgit Frauscher
- Montreal Neurological Institute and Hospital, McGill University, Montreal, Québec, Canada.,Department of Medicine and Center for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada
| | - Nicolás von Ellenrieder
- Montreal Neurological Institute and Hospital, McGill University, Montreal, Québec, Canada.,CONICET - LEICI, National University of La Plata, La Plata, Argentina
| | - François Dubeau
- Montreal Neurological Institute and Hospital, McGill University, Montreal, Québec, Canada
| | - Jean Gotman
- Montreal Neurological Institute and Hospital, McGill University, Montreal, Québec, Canada
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Gelinas JN, Khodagholy D, Thesen T, Devinsky O, Buzsáki G. Interictal epileptiform discharges induce hippocampal-cortical coupling in temporal lobe epilepsy. Nat Med 2016; 22:641-8. [PMID: 27111281 PMCID: PMC4899094 DOI: 10.1038/nm.4084] [Citation(s) in RCA: 170] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 03/14/2016] [Indexed: 12/15/2022]
Abstract
Interactions between the hippocampus and cortex are critical for memory. Interictal epileptiform discharges (IEDs) identify epileptic brain regions and can impair memory, but how they interact with physiological patterns of network activity is mostly undefined. We show in a rat model of temporal lobe epilepsy that spontaneous hippocampal IEDs correlate with impaired memory consolidation and are precisely coordinated with spindle oscillations in the prefrontal cortex during NREM sleep. This coordination surpasses the normal physiological ripple-spindle coupling and is accompanied by decreased ripple occurrence. IEDs also induce spindles during REM sleep and wakefulness, behavioral states that do not naturally express these oscillations, by generating a cortical ‘DOWN’ state. We confirm a similar correlation of temporofrontal IEDs with spindles over anatomically restricted cortical regions in a pilot clinical examination of four subjects with focal epilepsy. These findings imply that IEDs may impair memory via misappropriation of physiological mechanisms for hippocampal-cortical coupling, suggesting a target to treat memory impairment in epilepsy.
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Affiliation(s)
- Jennifer N Gelinas
- The Neuroscience Institute, New York University, School of Medicine, New York, New York, USA
| | - Dion Khodagholy
- The Neuroscience Institute, New York University, School of Medicine, New York, New York, USA
| | - Thomas Thesen
- Department of Neurology, Comprehensive Epilepsy Center, New York University, School of Medicine, New York, New York, USA
| | - Orrin Devinsky
- Department of Neurology, Comprehensive Epilepsy Center, New York University, School of Medicine, New York, New York, USA
| | - György Buzsáki
- The Neuroscience Institute, New York University, School of Medicine, New York, New York, USA.,Center for Neural Science, New York University, School of Medicine, New York, New York, USA
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Gibbs SA, Proserpio P, Terzaghi M, Pigorini A, Sarasso S, Lo Russo G, Tassi L, Nobili L. Sleep-related epileptic behaviors and non-REM-related parasomnias: Insights from stereo-EEG. Sleep Med Rev 2016; 25:4-20. [DOI: 10.1016/j.smrv.2015.05.002] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 04/13/2015] [Accepted: 05/07/2015] [Indexed: 10/23/2022]
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Delil S, Senel GB, Demiray DY, Yeni N. The role of sleep electroencephalography in patients with new onset epilepsy. Seizure 2015; 31:80-3. [DOI: 10.1016/j.seizure.2015.07.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2015] [Revised: 07/15/2015] [Accepted: 07/16/2015] [Indexed: 10/23/2022] Open
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Arbasino C, Calorio F, d’Orsi G, Marchioni E, Tartara E, Marchese D, Rustioni V, Moglia A, Galimberti CA. Interictal spiking in adult newly-diagnosed focal epilepsy of unknown cause: The effect of age. Clin Neurophysiol 2015; 126:1498-504. [DOI: 10.1016/j.clinph.2014.10.155] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 09/26/2014] [Accepted: 10/27/2014] [Indexed: 11/29/2022]
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17
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Tezer FI, Rémi J, Erbil N, Noachtar S, Saygi S. A reduction of sleep spindles heralds seizures in focal epilepsy. Clin Neurophysiol 2014; 125:2207-2211. [DOI: 10.1016/j.clinph.2014.03.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 02/25/2014] [Accepted: 03/04/2014] [Indexed: 11/16/2022]
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Carotenuto M, Parisi P, Esposito M, Cortese S, Elia M. Sleep alterations in children with refractory epileptic encephalopathies: a polysomnographic study. Epilepsy Behav 2014; 35:50-3. [PMID: 24802904 DOI: 10.1016/j.yebeh.2014.03.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2014] [Revised: 03/08/2014] [Accepted: 03/10/2014] [Indexed: 11/17/2022]
Abstract
Data on the relationship between sleep disturbances and refractory epileptic encephalopathies (EEs) are scarce. Our aim was to assess, by means of nocturnal polysomnography, if children with EEs present with objective alterations in sleep organization. Twenty-three children with EEs (12 males; mean age: 8.7±1.4years) and 40 healthy controls (22 males; mean age: 8.8±1.1years) underwent an overnight full polysomnography (PSG). Relative to controls, children with EEs showed a significant reduction in all PSG parameters related to sleep duration time in bed (TIB-min p<0.001), total sleep time (TST-min p<0.001), and sleep percentage (SPT-min p<0.001), as well as significantly higher REM latency (FRL-min p<0.001), rate in stage shifting (p=0.005), and number of awakenings/hour (p=0.002). Relative to controls, children with EEs also showed significant differences in respiratory parameters (AHI/h p<0.001, ODI/h p<0.001, SpO2% p<0.001, SpO2 nadir% p<0.001) and a higher rate of periodic limb movements (PLMs% p<0.001). Our findings suggest that sleep evaluation could be considered mandatory in children with refractory epileptic encephalopathy in order to improve the clinical management and the therapeutic strategies.
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Affiliation(s)
- Marco Carotenuto
- Clinic of Child and Adolescent Neuropsychiatry, Department of Mental Health, Physical and Preventive Medicine, Second University of Naples, Via Sergio Pansini 5, 80131 Naples, Italy.
| | - Pasquale Parisi
- Child Neurology, Pediatric Headache & Sleep Disorders Centre, Chair of Pediatrics, NESMOS Department, Faculty of Medicine and Psychology, "Sapienza University", Via Di Grottarossa 1035-1039, 00189 Rome, Italy.
| | - Maria Esposito
- Clinic of Child and Adolescent Neuropsychiatry, Department of Mental Health, Physical and Preventive Medicine, Second University of Naples, Via Sergio Pansini 5, 80131 Naples, Italy.
| | - Samuele Cortese
- Cambridge University Hospitals NHS Foundation Trust, Cambridge CB2 0QQ, UK.
| | - Maurizio Elia
- Oasi Institute for Research on Mental Retardation and Brain Aging (IRCCS), Via Conte Ruggiero 73, 94018 Troina (EN), Italy.
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Why are seizures rare in rapid eye movement sleep? Review of the frequency of seizures in different sleep stages. EPILEPSY RESEARCH AND TREATMENT 2013; 2013:932790. [PMID: 23853720 PMCID: PMC3703322 DOI: 10.1155/2013/932790] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Accepted: 05/16/2013] [Indexed: 12/25/2022]
Abstract
Since the formal characterization of sleep stages, there have been reports that seizures may preferentially occur in certain phases of sleep. Through ascending cholinergic connections from the brainstem, rapid eye movement (REM) sleep is physiologically characterized by low voltage fast activity on the electroencephalogram, REMs, and muscle atonia. Multiple independent studies confirm that, in REM sleep, there is a strikingly low proportion of seizures (~1% or less). We review a total of 42 distinct conventional and intracranial studies in the literature which comprised a net of 1458 patients. Indexed to duration, we found that REM sleep was the most protective stage of sleep against focal seizures, generalized seizures, focal interictal discharges, and two particular epilepsy syndromes. REM sleep had an additional protective effect compared to wakefulness with an average 7.83 times fewer focal seizures, 3.25 times fewer generalized seizures, and 1.11 times fewer focal interictal discharges. In further studies REM sleep has also demonstrated utility in localizing epileptogenic foci with potential translation into postsurgical seizure freedom. Based on emerging connectivity data in sleep, we hypothesize that the influence of REM sleep on seizures is due to a desynchronized EEG pattern which reflects important connectivity differences unique to this sleep stage.
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Poblano A, Haro R, Angel-Alavez G. Catamenial-sleep epilepsy: A case report. Sleep Biol Rhythms 2013. [DOI: 10.1111/sbr.12014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Adrián Poblano
- Clinic of Sleep Disorders at General Hospital of Mexico; School of Medicine; National University of México (UNAM); Mexico City; México
| | - Reyes Haro
- Clinic of Sleep Disorders at General Hospital of Mexico; School of Medicine; National University of México (UNAM); Mexico City; México
| | - Gerson Angel-Alavez
- Clinic of Sleep Disorders at General Hospital of Mexico; School of Medicine; National University of México (UNAM); Mexico City; México
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“Ectopic” theta oscillations and interictal activity during slow-wave state in the R6/1 mouse model of Huntington's disease. Neurobiol Dis 2012; 48:409-17. [DOI: 10.1016/j.nbd.2012.07.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 07/12/2012] [Accepted: 07/17/2012] [Indexed: 01/29/2023] Open
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Pereira AM, Bruni O, Ferri R, Palmini A, Nunes ML. The impact of epilepsy on sleep architecture during childhood. Epilepsia 2012; 53:1519-25. [DOI: 10.1111/j.1528-1167.2012.03558.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Bruni O, Novelli L, Mallucci A, Corte MD, Romeo A, Ferri R. Benign Rolandic and Occipital Epilepsies of Childhood. Sleep Med Clin 2012. [DOI: 10.1016/j.jsmc.2011.12.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Abstract
When the brain is awake, neurons in the cerebral cortex fire irregularly and the electroencephalogram (EEG) displays low amplitude, high frequency fluctuations. After falling asleep, neurons start oscillating between ON periods, when they fire as during wake, and OFF periods, when they stop firing altogether, and the EEG displays high amplitude slow waves. But what happens to neuronal firing after a long period of wake? We show here in freely behaving rats that, after prolonged wake, cortical neurons can go briefly “OFF line” as they do in sleep, accompanied by slower waves in the local EEG. Strikingly, neurons often go OFF line in one cortical area and not in another. During these periods of “local sleep”, whose incidence increases with wake duration, rats appear awake, active, and display a wake EEG. However, they are progressively impaired in a sugar pellet reaching task. Thus, though both the EEG and behavior indicate wakefulness, local populations of neurons in the cortex may be falling asleep, with negative consequences on performance.
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Bruni O, Novelli L, Luchetti A, Zarowski M, Meloni M, Cecili M, Villa M, Ferri R. Reduced NREM sleep instability in benign childhood epilepsy with centro-temporal spikes. Clin Neurophysiol 2010; 121:665-71. [PMID: 20097604 DOI: 10.1016/j.clinph.2009.12.027] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2009] [Revised: 12/17/2009] [Accepted: 12/20/2009] [Indexed: 01/04/2023]
Abstract
OBJECTIVE To analyze sleep architecture and NREM sleep instability by means of the cyclic alternating pattern (CAP) in children with benign epilepsy with rolandic spikes (BERS). METHODS Ten children with BERS, drug free at the time of the study and 10 age-matched normal controls were included in this study. Sleep was visually scored for sleep architecture and CAP using standard criteria. RESULTS Sleep architecture in BERS showed only few significant differences vs. controls with a reduction of total sleep time, sleep efficiency, and REM sleep percentage. CAP analysis revealed several significant differences: reduced total CAP rate, mainly in sleep stage 2, and reduced EEG slow oscillations and arousals during stages N1 and N2. CONCLUSIONS Sleep architecture is not importantly affected in BERS but CAP analysis reveals a decrease of NREM instability, mainly in sleep stage 2. Since there is a spindle-related spike activation in BERS, we speculate that the decrease of CAP and of EEG slow oscillations and arousals might be linked with the inhibitory action of spindling activity and spikes on arousals. SIGNIFICANCE CAP analysis discloses sleep structure abnormalities in children with BERS not shown by the classical sleep scoring. Spike activity and CAP A1 subtypes seem to be mutually exclusive probably because centro-temporal spikes disturb the physiological synchronization mechanisms needed for the generation of slow-wave components of CAP.
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Affiliation(s)
- Oliviero Bruni
- Pediatric Sleep Center, Department Developmental Neurology and Psychiatry, Sapienza University, Rome, Italy.
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Fenoglio-Simeone KA, Wilke JC, Milligan HL, Allen CN, Rho JM, Maganti RK. Ketogenic diet treatment abolishes seizure periodicity and improves diurnal rhythmicity in epileptic Kcna1-null mice. Epilepsia 2009; 50:2027-34. [PMID: 19490051 DOI: 10.1111/j.1528-1167.2009.02163.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Seizures are known to perturb circadian rhythms in humans as well as in animal models of epilepsy. However, it is unknown whether treatment of the underlying epilepsy restores normal biologic rhythms. We asked whether: (1) seizure activity is characterized by diurnal rhythmicity, (2) chronically epileptic mice exhibit impaired rest-activity rhythms, and (3) treatment with the anticonvulsant ketogenic diet (KD) improves such perturbations. METHODS Chronically epileptic Kcna1-null mice were fed either a standard diet (SD) or KD for 4 weeks and subjected to continuous video-EEG (electroencephalography) and actigraphy monitoring for 3-5 days to assess seizure activity and rest-activity cycles. RESULTS Seizure activity in Kcna1-null mice demonstrated diurnal rhythmicity, peaking at zeitgeber (ZT)2.30 +/- 1.52. Rest-activity rhythms of epileptic mice were significantly disrupted. Whereas locomotor activity for wild-type mice peaked at ZT15.45 +/- 0.28 (ZT14:26-ZT16:51), peak activity of epileptic mice was more unpredictable, occurring over a 12.4 h range (ZT06:33-ZT18:57). In six of nine epileptic mice, peak activity was delayed to ZT17.42 +/- 0.38, whereas peak activity was advanced to ZT10.00 +/- 1.26 in the remaining mice. Treatment with the KD abolished seizure periodicity and restored the rest-activity rhythm to values resembling those of wild-type mice (i.e., activity peaking at ZT16.73 +/- 0.67). CONCLUSIONS Kcna1-null mice experience seizures with 24-h periodicity and impaired circadian behavior. KD reduces the number and periodicity of seizures and restores normal behavioral rhythms, suggesting that this nonpharmacologic therapy may benefit biologic rhythm disturbances in epileptic patients.
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Affiliation(s)
- Kristina A Fenoglio-Simeone
- Barrow Neurological Institute and St. Joseph's Medical Center, Neurology Research, Phoenix, Arizona 85013, USA
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Non-REM sleep influences results of fMRI studies in epilepsy. Neurosci Lett 2008; 443:61-6. [DOI: 10.1016/j.neulet.2008.07.044] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2007] [Revised: 06/05/2008] [Accepted: 07/04/2008] [Indexed: 11/23/2022]
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Myatchin I, Lagae L. Sleep spindle abnormalities in children with generalized spike-wave discharges. Pediatr Neurol 2007; 36:106-11. [PMID: 17275662 DOI: 10.1016/j.pediatrneurol.2006.09.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2006] [Revised: 08/29/2006] [Accepted: 09/25/2006] [Indexed: 10/23/2022]
Abstract
This study investigated sleep and sleep spindle parameters in children with primary generalized spike-and-wave discharges (untreated primary generalized group, nine patients; treated primary generalized group, six patients) and compared these with an age- and sex-matched nonepileptic control group (n = 47). In the untreated primary generalized group, stage 2 onset was significantly shorter, with less spindles in stage 2. In the last stage 2 period of the night, significantly less fast frequency spindles were observed, indicating abnormal dynamics of sleep architecture. In the treated group, sleep patterns were comparable to that of the control group. The data indicate sleep architecture dysfunctions in children with generalized spike-and-wave discharges. These dysfunctions could account for the frequently encountered sleep problems in children with primary generalized epilepsy.
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Affiliation(s)
- Ivan Myatchin
- University Hospitals KULeuven, Division Pediatric Neurology, Leuven, Belgium
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PASTOR J, DELAPRIDA L, HERNANDO V, SOLA R. Voltage sources in mesial temporal lobe epilepsy recorded with foramen ovale electrodes. Clin Neurophysiol 2006; 117:2604-14. [PMID: 17029955 DOI: 10.1016/j.clinph.2006.07.311] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2005] [Revised: 07/13/2006] [Accepted: 07/26/2006] [Indexed: 11/28/2022]
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Foldvary-Schaefer N, Grigg-Damberger M. Sleep and epilepsy: what we know, don't know, and need to know. J Clin Neurophysiol 2006; 23:4-20. [PMID: 16514348 DOI: 10.1097/01.wnp.0000206877.90232.cb] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Long-term video-EEG and, more recently, video-polysomnography, have provided the means to confirm and expand on the interconnections between sleep and epilepsy. Some of these relationships have become firmly established. When one of the authors (N.F.S.) presented part of this paper at a symposium on the Future of Sleep in Neurology at an American Clinical Neurophysiology Society annual meeting in 2004, the purpose was to summarize what we know, don't know, and need to know about the effects of sleep on epilepsy and epilepsy on sleep. Here we seek to summarize some of the more firmly established relationships between sleep and epilepsy and identify intriguing associations that require further elucidation.
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Clemens Z, Janszky J, Clemens B, Szucs A, Halász P. Factors affecting spiking related to sleep and wake states in temporal lobe epilepsy (TLE). Seizure 2005; 14:52-7. [PMID: 15642501 DOI: 10.1016/j.seizure.2004.09.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The aim of the study was to investigate the influence of different clinical factors on spiking during sleep and wakefulness in temporal lobe epilepsy. The study included 38 temporal lobe epilepsy (TLE) patients who underwent long-term electroencephalography (EEG) monitoring. In addition to traditional sleep scoring, waking was subdivided into eyes opened (WEO) and eyes closed (WEC) states. The following spike measures were investigated: spiking rates for each state, mean spike rate, spiking stability across wake and sleep states and relative spike density for each state. These measures were investigated according to clinical variables, such as age, age at epilepsy onset, duration of epilepsy, seizure frequency, the presence of secondarily generalised tonic-clonic (SGTC) seizures and the data on epileptogenic lesions based on MRI. Spiking rates during most states and spiking stability showed a significant positive correlation with epilepsy duration. Relative spike density during sleep stage NREM3,4 significantly increased with age at epilepsy onset. Relative spike density during WEC was significantly higher in the presence of hippocampal sclerosis (HS). Spiking rate during REM was significantly higher if a patient had SGTC seizures. Our data provide evidence that different aspects of spiking are associated with different aspects of TLE. We suggest that spike behaviour analysis offer new aspects both for diagnosis and research.
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Affiliation(s)
- Zsófia Clemens
- Országos Pszichiátriai és Neurológiai Intézet, I. Neurológia, H-1021 Budapest, Huvösvölgyi út 116, Hungary.
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Clemens Z, Janszky J, Szucs A, Békésy M, Clemens B, Halász P. Interictal epileptic spiking during sleep and wakefulness in mesial temporal lobe epilepsy: a comparative study of scalp and foramen ovale electrodes. Epilepsia 2003; 44:186-92. [PMID: 12558572 DOI: 10.1046/j.1528-1157.2003.27302.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To assess distribution of temporal lobe spikes across different states of sleep and wakefulness in simultaneous scalp and foramen ovale (Fo) recordings. METHODS The study included 12 patients with mesial temporal lobe epilepsy (MTLE). As part of their presurgical evaluation, patients underwent long-term video-EEG monitoring with combined scalp and foramen ovale electrodes (FoEs). In addition to traditional sleep scoring, waking was subdivided into eyes-opened and eyes-closed states, and rapid-eye-movement (REM) sleep was divided into phasic and tonic states. Spike counts were carried out visually for scalp and FoEs, and spiking rates were determined for each state. A ratio between FoE and scalp spiking rates also was calculated for each state. RESULTS Scalp spiking showed a significant increase during NREM3,4, whereas FoE spiking increased during NREM2. The scalp/FoE ratio significantly increased during NREM3,4. A significant difference in spiking rate also was found between phasic and tonic REM states as well as between waking with eyes opened and closed in FoE recordings. CONCLUSIONS Our data provide evidence of a discrepancy in spike distribution across different states of sleep and waking monitored by scalp and FoE recordings. We suggest that these discrepancies may reflect differences in archicortical and neocortical spike synchronization.
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Affiliation(s)
- Zsófia Clemens
- Department of Neurology, Epilepsy Center, National Institute of Psychiatry and Neurology, Budapest, Hungary.
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Nobili L, Baglietto MG, Beelke M, De Carli F, De Negri E, Gaggero R, Rosadini G, Veneselli E, Ferrillo F. Distribution of epileptiform discharges during nREM sleep in the CSWSS syndrome: relationship with sigma and delta activities. Epilepsy Res 2001; 44:119-28. [PMID: 11325568 DOI: 10.1016/s0920-1211(01)00191-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
PURPOSE The EEG pattern of epilepsy with continuous spike-waves during slow wave sleep (CSWSS) is characterized by an almost continuous activation of spike-and-slow-wave complexes during nREM sleep with a marked reduction of EEG abnormalities during REM sleep and the awake state. Experimental studies indicate that normal sleep oscillations that during nREM sleep lead to the appearance of spindles and delta waves on scalp EEG might develop into paroxysmal synchronization. Spectral analysis enables the quantitative description of the dynamics of delta (Delta Activity, DA, 0.5-4.5 Hz) and sigma activity (SA, 12-16 Hz) and can be used to assess the relationship between SA, DA and epileptiform discharges (EDs) during sleep. METHODS We analyzed the EDs distribution during sleep in five children affected by CSWSS. We used a model of the evolution of power of DA and SA to which the time series of EDs could be fitted. RESULTS We found a high and positive correlation between EDs and SA. DA resulted negatively correlated with EDs. CONCLUSION Our data suggest that neural mechanisms involved in the generation of sleep spindles facilitate EDs production in the CSWSS syndrome. Such a mechanism seems to be an age related phenomenon shared by other epileptic syndromes of childhood.
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Affiliation(s)
- L Nobili
- Center of Sleep Medicine, DISMR, University of Genoa, Genoa, Italy.
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Ferrillo F, Beelke M, Nobili L. Sleep EEG synchronization mechanisms and activation of interictal epileptic spikes. Clin Neurophysiol 2000; 111 Suppl 2:S65-73. [PMID: 10996557 DOI: 10.1016/s1388-2457(00)00404-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE The temporal course of sleep interictal epileptic discharges (IEDs) has been studied focusing their relationship with the temporal course of the main sleep-EEG frequency bands that is thought to reflect the action of different synchronization neural mechanisms. The existence of a mutually exclusive mechanism between spindles and delta waves should be reflected in a mutually exclusive facilitation of IEDs activation by slow wave activity (SWA) and sigma activity (SA) during synchronized NREM sleep. METHODS We reanalyzed data from 19 children and 15 adult patients affected by different partial epileptic syndromes. The temporal series of SWA, SA and theta band (TB), derived from spectral analysis, were obtained from a spike-free and pathologic alteration-free derivation, controlateral to the most active lead, where the IEDs count was performed. Relationships between SA, SWA and TB and time series of IEDs were tested by means of correlation techniques after data normalization. RESULTS A positive correlation of spike distribution with SWA time course has been found in the majority of adults. Only a few adult patients showed IEDs that were correlated with SA or TB. Conversely SA was shown to be positively correlated with spiking in many different epileptic syndromes of childhood. Moreover, in the contest of the NREM sleep cycle an inverse relationship between the SWA and SA mode of spike activation has been detected. CONCLUSIONS Overall results give evidence that 3 main rhythmic spectral components that characterize sleep EEG can exert positive influences on IEDs production. Our studies demonstrate that within NREM sleep the facilitating influences on IEDs production exerted separately by either spindle activity or delta synchronization mechanisms can be detected. Moreover, a mutually exclusive mechanism between SA and SWA oscillations is detectable in the opposite relationship of the correlation between IEDs and the two bands in the central part of the NREM cycle.
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Affiliation(s)
- F Ferrillo
- Center of Sleep Medicine, Chair of Neurophysiopathology, DISMR, University of Genoa, Genoa, Italy.
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Beelke M, Nobili L, Baglietto MG, De Carli F, Robert A, De Negri E, Ferrillo F. Relationship of sigma activity to sleep interictal epileptic discharges: a study in children affected by benign epilepsy with occipital paroxysms. Epilepsy Res 2000; 40:179-86. [PMID: 10863145 DOI: 10.1016/s0920-1211(00)00131-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
INTRODUCTION By applying spectral analysis techniques we recently showed that Interictal Epileptic Discharges (IEDs) are modulated by sleep spindle synchronization mechanisms (sigma activity, SA, 12. 0-16.0 Hz). This finding applies to both benign epilepsy of childhood with rolandic spikes (BECRS), to symptomatic epilepsy of childhood strongly activated by sleep and to the Landau-Kleffner syndrome. These results are quite different from those found in adult partial epileptic patients where slow wave activity (SWA, 0. 5-4.5 Hz) plays the main role in the modulation of IEDs during sleep. This finding could suggest that the activation of IEDs by spindle activities could be an age-related feature of epilepsy. In order to verify this hypothesis we studied a group of epileptic children performing a polysomnographic study on five patients with BEOP strongly activated by sleep. METHODS We performed overnight continuous EEG-polysomnographic studies in five patients (mean age 6. 0+/-2.5). The IEDs count was performed on the most active occipital lead. The temporal series of SWA and SA values, derived from spectral analysis, were obtained from a spike-free central, controlateral lead. Relationships between SA, SWA and time series of IEDs were tested by means of correlation techniques after data normalization. RESULTS Our results revealed a significantly higher correlation between IEDs and SA with respect to SWA in all subjects, in total sleep time. When the analysis was limited only to NREM sleep the correlation between sigma and IEDs was even more impressive. CONCLUSIONS Data suggest that also in BEOP the spindle generating mechanism modulates the IEDs during sleep. This mechanism seems to be an age-dependent phenomenon with no relation whatsoever either with the type of epilepsy or with the brain region.
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Affiliation(s)
- M Beelke
- Center of Sleep Medicine, DISMR, University of Genoa, Genoa, Italy.
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