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Yayıcı Köken Ö, Şekeroğlu B, Şanlıdağ B, Sarı Yanartaş M, Yılmaz A. Focality in childhood absence epilepsy. Neurol Res 2024; 46:626-633. [PMID: 38643974 DOI: 10.1080/01616412.2024.2339114] [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: 10/06/2023] [Accepted: 03/31/2024] [Indexed: 04/23/2024]
Abstract
BACKGROUND AND PURPOSE Childhood absence epilepsy (CAE) has a typical electroencephalography (EEG) pattern of generalized 3 Hz spike and wave discharges (SWD). Focal interictal discharges were also documented in a small number of documents. The aim was to investigate the amplitudes of interictal 3 Hz SWD within the 1st second in drug-naïve CAE patients. In this way, areas with maximal electronegativity at the beginning of clinically generalized discharges will be documented. METHODS The EEG records of children with drug-naïve CAE were evaluated retrospectively by two child neurologists first for 3 Hz SWD. Then, a machine-learning model evaluated the amplitudes of 3 Hz in the 1st second of SWD. Maximum electronegativity areas were documented and classified as focal, bilateral, and generalized. RESULTS One hundred and twelve 3 Hz SWD were evaluated in 11 patients. Among discharges within the 1st second, maximum electronegativity areas were documented as focal for 44 (39.2%), bilateral for 8 (7.1%), generalized for 60 (53.5%). Among focal electronegativity areas, mostly right central, left occipital and midline parietal areas were documented in 12 (10.7%), 7 (6.2%), and 6 (5.3%), respectively. Eight (7.1%) of the maximum electronegativity areas were detected bilaterally, of which 7 (6.2%) originated from the frontopolar areas. CONCLUSIONS Focal maximal electronegativity areas were frequently observed in drug-naïve CAE patients, comprising approximately half of non-generalized discharges. Focal discharges might be misleading in diagnosis. Focal areas within the brain may be responsible for and contribute to absence seizures that appear bilaterally symmetrical and generalized clinically. Although its clinical implication is unknown, this warrants further study.
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Affiliation(s)
- Özlem Yayıcı Köken
- Faculty of Medicine, Department of Pediatric Neurology, Akdeniz University, Antalya, Turkey
| | - Boran Şekeroğlu
- Artificial Intelligence Engineering, Near East University, Nicosia, Cyprus
- DESAM Institute, Near East University, Nicosia, Cyprus
| | - Burçin Şanlıdağ
- Faculty of Medicine, Department of Pediatric Neurology, Near East University, Nicosia, Cyprus
| | - Mehpare Sarı Yanartaş
- Faculty of Medicine, Department of Pediatric Neurology, Akdeniz University, Antalya, Turkey
| | - Arzu Yılmaz
- Ministry of Health, Ankara Research and Training Hospital, Department of Pediatric Neurology, Ankara, Turkey
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Özçelik EU, Çokar Ö, Demirbilek V. Pretreatment electroencephalographic features in patients with childhood absence epilepsy. Neurophysiol Clin 2022; 52:280-289. [PMID: 35953417 DOI: 10.1016/j.neucli.2022.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 07/11/2022] [Accepted: 07/12/2022] [Indexed: 10/15/2022] Open
Abstract
OBJECTIVE To analyze the ictal and interictal electroencephalographic (EEG) features in newly diagnosed childhood absence epilepsy (CAE) and determine the association between seizure onset topography, interictal focal spike-wave discharges (FSWDs) and accompanying clinical features of absence seizures. METHODS The authors searched the EEG database for a definite diagnosis of CAE according to ILAE 2017 criteria. Video-EEGs of untreated pediatric patients during sleep and wakefulness were evaluated retrospectively. RESULTS The study included 47 patients (25 males, 22 females). Interictal FSWDs were observed in 49% of patients with CAE during wakefulness and in 85.1% during sleep (p = 0.001). Interictal FSWDs were most frequently observed in the frontal regions (awake: 34%; asleep: 74.5%), followed by the posterior temporoparietooccipital region (awake: 21.2%; asleep: 36.1%), and the centrotemporal region (awake: 6.4%; asleep: 8.5%). Eleven patients (23.4%) had polyspikes during sleep. Both bilateral symmetric and asymmetric seizure onset were noted in 32%, whereas focal seizure onset was observed in 14.9% of the patients. Absence seizures with and without motor components were seen in 72.3% and 61.7% of patients, respectively, and in 33% of patients both occurred. There were no associations between the existence of interictal FSWDs, focal/asymmetric seizure onset, and absence seizures with and/or without motor components. CONCLUSION Asymmetric and/or focal seizure onset, interictal FSWDs, and absence seizures with motor components are commonly observed in drug-naive CAE. This study found no association between seizure onset topography, interictal FSWDs, and semiological features of absence seizures.
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Affiliation(s)
- Emel Ur Özçelik
- Istanbul University, Cerrahpaşa School of Medicine, Departments of Neurology and Childhood Neurology, Istanbul, Türkiye; Istanbul Health and Technology University, Faculty of Health Sciences, Department of Ergotherapy, Istanbul, Türkiye.
| | - Özlem Çokar
- University of Health Sciences, Hamidiye School of Medicine, Haseki Educational and Research Hospital, Department of Neurology, Istanbul, Türkiye
| | - Veysi Demirbilek
- Istanbul University, Cerrahpaşa School of Medicine, Departments of Neurology and Childhood Neurology, Istanbul, Türkiye
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Fauser S, Cloppenborg T, Polster T, Specht U, Woermann FG, Bien CG. Genetic generalized epilepsies with frontal lesions mimicking migratory disorders on the epilepsy monitoring unit. Epilepsia Open 2020; 5:176-189. [PMID: 32524043 PMCID: PMC7278548 DOI: 10.1002/epi4.12385] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 02/05/2020] [Accepted: 02/11/2020] [Indexed: 11/08/2022] Open
Abstract
Objective Some patients with genetic generalized epilepsy (GGE) may present with ambiguous and atypical findings and even focal brain abnormalities. Correct diagnosis may therefore be difficult. Methods We retrospectively collected six patients investigated on the epilepsy monitoring unit with MRI abnormalities mimicking focal cortical dysplasia (FCD-like) or heterotopias, but with semiology and EEG features of GGE. We compared them to four additional patients with GGE and nonmigratory abnormalities. Results All six patients presented with frontal MRI lesions: radial ("transmantle," n = 4), cortical-subcortical (n = 1), and periventricular heterotopia (n = 1). Five had positive family histories. Semiologic lateralizing signs compatible with the lesion were seen in four. Five patients had 3/s spike-wave complexes, with an asymmetric appearance in three. Regional EEG changes matched with the side of the abnormality in three patients. Invasive EEG (n = 2) or postoperative outcomes (n = 3) argued against an ictogenic role of the MRI abnormalities. Histology showed mild malformation of cortical development, but no focal cortical dysplasia. The six patients were finally diagnosed with juvenile myoclonic epilepsy (n = 2), juvenile absence epilepsy (n = 2), or GGE not further specified (nfs, n = 2). Compared to these patients, the other four (final diagnoses: childhood absence epilepsy, n = 1; perioral myoclonia with absences, n = 1; and GGE nfs, n = 2) had no lateralizing EEG findings. Significance Patients with GGE may have coincidental MRI abnormalities. These cases are challenging as frontal epilepsy and GGE can present with similar semiologies. GGE with coincidental FCD-like lesions/heterotopias is in particular difficult to diagnose as patients have more lateralizing features (in semiology and EEG) than those with tumors. A detailed noninvasive presurgical evaluation may be justified. We point out red flags that may help to distinguish GGE from frontal epilepsy, even in the presence of brain abnormalities: 3/s spike waves (even if asymmetric), changing lateralizing signs at different times, and a positive family history hinting at GGE.
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Affiliation(s)
- Susanne Fauser
- Epilepsy Center Bethel Krankenhaus Mara Bielefeld Germany
| | | | - Tilman Polster
- Epilepsy Center Bethel Krankenhaus Mara Bielefeld Germany
| | - Ulrich Specht
- Epilepsy Center Bethel Krankenhaus Mara Bielefeld Germany
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Gulati P, Jain P, Qashqari H, Bradbury L, Cooper P, Otsubo H, Whitney R. Peri-oral myoclonia with absences with multiple facial and upper body myoclonia: Overlap epilepsy syndrome. J Clin Neurosci 2018; 54:135-137. [PMID: 29907391 DOI: 10.1016/j.jocn.2018.06.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 06/04/2018] [Indexed: 10/14/2022]
Abstract
A 17-years old girl presented with an 8-year history of absences with peri-oral twitching, eyelid twitching and head nodding, with poor response to anti-epileptic drugs. Video EEG revealed ictal and inter-ictal generalized spike wave discharges, and absences with peri-oral (predominant), eyelid, neck and shoulder myoclonia. There was also prominent eye closure sensitivity. Conundrums regarding epilepsy syndrome classification and pathophysiology are discussed.
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Affiliation(s)
- Pratima Gulati
- Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada.
| | - Puneet Jain
- Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada.
| | - Hebah Qashqari
- Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada.
| | - Laura Bradbury
- Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada.
| | - Pamela Cooper
- Community Pediatric Neurologist, Stouffville, Ontario, Canada.
| | - Hiroshi Otsubo
- Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada.
| | - Robyn Whitney
- Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada.
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Martín-López D, Jiménez-Jiménez D, Cabañés-Martínez L, Selway RP, Valentín A, Alarcón G. The Role of Thalamus Versus Cortex in Epilepsy: Evidence from Human Ictal Centromedian Recordings in Patients Assessed for Deep Brain Stimulation. Int J Neural Syst 2017; 27:1750010. [DOI: 10.1142/s0129065717500101] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Background: The onset of generalized seizures is a long debated subject in epilepsy. The relative roles of cortex and thalamus in initiating and maintaining the different seizure types are unclear. Objective: The purpose of the study is to estimate whether the cortex or the centromedian thalamic nucleus is leading in initiating and maintaining seizures in humans. Methods: We report human ictal recordings with simultaneous thalamic and cortical electrodes from three patients without anesthesia being assessed for deep brain stimulation (DBS). Patients 1 and 2 had idiopathic generalized epilepsy whereas patient 3 had frontal lobe epilepsy. Visual inspection was combined with nonlinear correlation analysis. Results: In patient 1, seizure onset was bilateral cortical and the belated onset of leading thalamic discharges was associated with an increase in rhythmicity of discharges, both in thalamus and cortex. In patient 2, we observed bilateral independent interictal discharges restricted to the thalamus. However, ictal onset was diffuse, with discharges larger in the cortex even though they were led by the thalamus. In patient 3, seizure onset was largely restricted to frontal structures, with belated lagging thalamic involvement. Conclusion: In human generalized seizures, the thalamus may become involved early or late in the seizure but, once it becomes involved, it leads the cortex. In contrast, in human frontal seizures the thalamus gets involved late in the seizure and, once it becomes involved, it lags behind the cortex. In addition, the centromedian nucleus of the thalamus is capable of autonomous epileptogenesis as suggested by the presence of independent focal unilateral epileptiform discharges restricted to thalamic structures. The thalamus may also be responsible for maintaining the rhythmicity of ictal discharges.
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Affiliation(s)
- David Martín-López
- Department of Clinical Neurophysiology, Kingston Hospital NHS FT, London, UK
- Department of Clinical Neurophysiology, St George’s University Hospitals NHS FT, London, UK
- Department of Basic and Clinical Neuroscience, King’s College London, Institute of Psychiatry, Psychology and Neuroscience, London, UK
- Departamento de Fisiología, Facultad de Medicina, Universidad Complutense, Madrid, Spain
| | - Diego Jiménez-Jiménez
- Department of Basic and Clinical Neuroscience, King’s College London, Institute of Psychiatry, Psychology and Neuroscience, London, UK
- Department of Clinical Neurophysiology, King’s College Hospital NHS FT, London, UK
- Universidad San Francisco de Quito, School of Medicine, Quito, Ecuador
| | | | - Richard P. Selway
- Department of Neurosurgery, King’s College Hospital NHS FT, London, UK
| | - Antonio Valentín
- Department of Basic and Clinical Neuroscience, King’s College London, Institute of Psychiatry, Psychology and Neuroscience, London, UK
- Departamento de Fisiología, Facultad de Medicina, Universidad Complutense, Madrid, Spain
- Department of Clinical Neurophysiology, King’s College Hospital NHS FT, London, UK
| | - Gonzalo Alarcón
- Department of Basic and Clinical Neuroscience, King’s College London, Institute of Psychiatry, Psychology and Neuroscience, London, UK
- Departamento de Fisiología, Facultad de Medicina, Universidad Complutense, Madrid, Spain
- Department of Clinical Neurophysiology, King’s College Hospital NHS FT, London, UK
- Comprehensive Epilepsy Center Neuroscience Institute, Academic Health Systems, Hamad Medical Corporation, Doha, Qatar
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Karimzadeh F, Modarres Mousavi SM, Ghadiri T, Jafarian M, Soleimani M, Sadeghi SM, Mesgari M, Joghataei MT, Gorji A. The Modulatory Effect of Metabotropic Glutamate Receptor Type-1α on Spike-Wave Discharges in WAG/Rij Rats. Mol Neurobiol 2016; 54:846-854. [PMID: 26780454 DOI: 10.1007/s12035-016-9692-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 01/05/2016] [Indexed: 02/06/2023]
Abstract
Modulatory function of metabotropic glutamate type 1 (mGlu1) receptors plays a crucial role in the pathophysiology of some neurological disorders, including schizophrenia and epilepsy. In this study, the expression of mGlu1α receptors in the thalamic nuclei was assessed during development of absence seizures in the WAG/Rij rats, a valid genetic animal model of absence epilepsy. In addition, the effect of pharmacological modulation of mGlu1α receptors in the laterodorsal (LD) nucleus of the thalamus on the characteristic features of bioelectrical brain activities in the WAG/Rij rats was assessed. The expression of mGlu1α receptors in the LD was assessed in four experimental groups of both WAG/Rij and Wistar rats with 2 and 6 months of age. Agonist and antagonist of mGlu1α receptors were infused in LD in the six months old WAG/Rij (epileptic) rats. The protein level of mGlu1α receptors in the thalamus of the 6-month-old WAG/Rij rats was lower than non-epileptic animals. In addition, the distribution of mGlu1α receptors in different thalamic nuclei was lower in the 6-month-old WAG/Rij compared to age-matched Wistar rats. The gene expression of mGlu1α receptor was also significantly lower in 6-month-old WAG/Rij rats in the LD compared to other animal groups. The microinjection of mGlu1α receptors agonist and antagonist in the LD reduced the duration of spike-wave discharges (SWDs) and increased the amplitude and duration of SWDs, respectively, in 6-month-old WAG/Rij rats. The alterations of mGlu1α receptors expression in the thalamus of epileptic WAG/Rij rats as well as its modulatory effects in the generation of SWDs suggest the potential of mGlu1 receptors as a therapeutic target in absence epilepsy.
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Affiliation(s)
- Fariba Karimzadeh
- Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran.,Shefa Neuroscience Research Center, Khatam Alanbia Hospital, Tehran, Iran
| | | | - Tahereh Ghadiri
- Shefa Neuroscience Research Center, Khatam Alanbia Hospital, Tehran, Iran
| | - Maryam Jafarian
- Shefa Neuroscience Research Center, Khatam Alanbia Hospital, Tehran, Iran
| | - Mansoureh Soleimani
- Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Shahin Mohammad Sadeghi
- Department of Plastic and Reconstructive Surgery, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Masoud Mesgari
- Klinik und Poliklinik für Neurochirurgie, Westfälische Wilhelms-Universität Münster, Münster, Germany.,Klinik und Poliklinik für Neurologie, Westfälische Wilhelms-Universität Münster, Münster, Germany.,Epilepsy Research Center, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | | | - Ali Gorji
- Shefa Neuroscience Research Center, Khatam Alanbia Hospital, Tehran, Iran. .,Klinik und Poliklinik für Neurochirurgie, Westfälische Wilhelms-Universität Münster, Münster, Germany. .,Klinik und Poliklinik für Neurologie, Westfälische Wilhelms-Universität Münster, Münster, Germany. .,Epilepsy Research Center, Westfälische Wilhelms-Universität Münster, Münster, Germany.
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Dugan P, Carlson C, Bluvstein J, Chong DJ, Friedman D, Kirsch HE. Auras in generalized epilepsy. Neurology 2014; 83:1444-9. [PMID: 25230998 DOI: 10.1212/wnl.0000000000000877] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE We studied the frequency of auras in generalized epilepsy (GE) using a detailed semistructured diagnostic interview. METHODS In this cross-sectional study, participants with GE were drawn from the Epilepsy Phenome/Genome Project (EPGP). Responses to the standardized diagnostic interview regarding tonic-clonic (grand mal) seizures were then examined. This questionnaire initially required participants to provide their own description of any subjective phenomena before their "grand mal seizures." Participants who provided answers to these questions were considered to have an aura. All participants were then systematically queried regarding a list of specific symptoms occurring before grand mal seizures, using structured (closed-ended) questions. RESULTS Seven hundred ninety-eight participants with GE were identified, of whom 530 reported grand mal seizures. Of these, 112 (21.3%) reported auras in response to the open-ended question. Analysis of responses to the closed-ended questions suggested that 341 participants (64.3%) experienced at least one form of aura. CONCLUSIONS Auras typically associated with focal epilepsy were reported by a substantial proportion of EPGP subjects with GE. This finding may support existing theories of cortical and subcortical generators of GE with variable spread patterns. Differences between responses to the open-ended question and closed-ended questions may also reflect clinically relevant variation in patient responses to history-taking and surveys. Open-ended questions may underestimate the prevalence of specific types of auras and may be in part responsible for the underrecognition of auras in GE. In addition, structured questions may influence participants, possibly leading to a greater representation of symptoms.
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Affiliation(s)
- Patricia Dugan
- From the Department of Neurology (P.D., J.B., D.J.C., D.F.), New York University Langone Medical Center, New York; Department of Neurology (C.C.), Medical College of Wisconsin, Milwaukee; and Department of Neurology (H.E.K.), University of California, San Francisco.
| | - Chad Carlson
- From the Department of Neurology (P.D., J.B., D.J.C., D.F.), New York University Langone Medical Center, New York; Department of Neurology (C.C.), Medical College of Wisconsin, Milwaukee; and Department of Neurology (H.E.K.), University of California, San Francisco
| | - Judith Bluvstein
- From the Department of Neurology (P.D., J.B., D.J.C., D.F.), New York University Langone Medical Center, New York; Department of Neurology (C.C.), Medical College of Wisconsin, Milwaukee; and Department of Neurology (H.E.K.), University of California, San Francisco
| | - Derek J Chong
- From the Department of Neurology (P.D., J.B., D.J.C., D.F.), New York University Langone Medical Center, New York; Department of Neurology (C.C.), Medical College of Wisconsin, Milwaukee; and Department of Neurology (H.E.K.), University of California, San Francisco
| | - Daniel Friedman
- From the Department of Neurology (P.D., J.B., D.J.C., D.F.), New York University Langone Medical Center, New York; Department of Neurology (C.C.), Medical College of Wisconsin, Milwaukee; and Department of Neurology (H.E.K.), University of California, San Francisco
| | - Heidi E Kirsch
- From the Department of Neurology (P.D., J.B., D.J.C., D.F.), New York University Langone Medical Center, New York; Department of Neurology (C.C.), Medical College of Wisconsin, Milwaukee; and Department of Neurology (H.E.K.), University of California, San Francisco
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Visual cortex hyperexcitability in idiopathic generalized epilepsies with photosensitivity: a TMS pilot study. Epilepsy Behav 2013; 27:301-6. [PMID: 23518608 DOI: 10.1016/j.yebeh.2013.02.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2012] [Revised: 02/11/2013] [Accepted: 02/13/2013] [Indexed: 11/22/2022]
Abstract
BACKGROUND The current understanding of the mechanisms underlying photosensitivity is still limited, although most studies point to a hyperexcitability of the visual cortex. METHODS Using transcranial magnetic stimulation, we determined the resting motor threshold (rMT) and the phosphene threshold (PT) in 33 patients with IGEs (8 with photosensitivity) compared with 12 healthy controls. RESULTS Eleven controls (92%) reported phosphenes compared with fifteen (46%) patients with idiopathic generalized epilepsy (p=0.015). Phosphenes were reported more frequently among patients with epilepsy with photosensitivity (87.5%) than in patients with active epilepsy without photosensitivity (30.8%) (p=0.038) and patients with epilepsy in remission without photosensitivity (33.3%) (p=0.054); no differences were found between patients with epilepsy with photosensitivity and controls (p=0.648). Resting motor threshold and phosphene threshold were significantly higher among patients with epilepsy (active epilepsy or epilepsy in remission without photosensitivity) compared to healthy controls (p<0.01). Conversely, patients with active epilepsy and photosensitivity had significantly lower values than controls (p=0.03). CONCLUSIONS The marked decrease in PT and the high phosphene prevalence in patients with IGE with photosensitivity indicate a regional hyperexcitability of the primary visual cortex. Results of this study also suggest that the PT may serve as a biomarker for excitability in patients with IGE and photosensitivity.
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Koutroumanidis M, Tsiptsios D, Kokkinos V, Kostopoulos GK. Focal and generalized EEG paroxysms in childhood absence epilepsy: topographic associations and distinctive behaviors during the first cycle of non-REM sleep. Epilepsia 2012; 53:840-9. [PMID: 22360352 DOI: 10.1111/j.1528-1167.2012.03424.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE To better understand the nature of the focal spike-wave discharges (FSWDs) and focally led generalized spike-wave discharges (GSWDs) in typical childhood absence epilepsy (CAE) and by implication their nosologic and taxonomic significance. METHODS Twenty-four abnormal video-electroencephalography (EEG) studies from 13 consecutive children with CAE and good response to appropriate antiepileptic drugs (AEDs) were analyzed. We studied the association between the topography of absence onset and the ictal automatisms, and the topographic correlation between FSWDs and GSWDs and their respective behavior during hyperventilation and the different states of phasic and nonphasic non-rapid eye movement (NREM) sleep. GSWDs were considered as of "focal" onset if a lead-in could be visibly recognized at a paper speed of 60 mm/s, and were classified by their topography. KEY FINDINGS (1) Multifocal absences occurred in 10 children; anterior onset was noted in 81 absences (73.6%) from 12 children and posterior in 18 (16.4%) from 7 children; there was no association between topography of absence onset and ictal automatisms; (2) FSWDs occurred in 85% of children and were multifocal in 73% of them; 85% of FSWDs were anterior and 14% posterior; (3) there was good topographic association between FSWDs and the leading spike of GSWDs of "focal" onset in all children with FSWDs; (4) both FSWDs and GSWDs increased during hyperventilation; (5) FSWDs occurred mainly during noncyclical NREM sleep and during periods of reduced vigilance of cyclical NREM sleep, whereas GSWDs occurred during the periods of enhanced vigilance of NREM sleep; GSWDs occurred significantly more frequently than FSWDs at the transition from reduced to enhanced vigilance of NREM sleep. SIGNIFICANCE Our findings suggest that in CAE focal EEG paroxysms reflect a system of multifocal nonlocalizing electrically unstable cortical areas that under the facilitatory influence of exogenous or endogenous factors like sleep instability can foster a corticothalamic response of sufficient strength to generate 3-Hz GSWDs that are conditionally sustainable and potentially ictal. FSWDs can be viewed as incomplete forms of the GSWDs; together they define the EEG identity of idiopathic "generalized" epileptogenesis.
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Affiliation(s)
- Michalis Koutroumanidis
- Department of Clinical Neurophysiology and Epilepsies, Guy's & St Thomas' NHS Foundation Trust, London, United Kingdom.
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10
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Mariani E, Rossi LN, Vajani S. Interictal paroxysmal EEG abnormalities in childhood absence epilepsy. Seizure 2011; 20:299-304. [DOI: 10.1016/j.seizure.2010.12.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Revised: 12/16/2010] [Accepted: 12/27/2010] [Indexed: 11/29/2022] Open
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11
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Vaudano AE, Laufs H, Kiebel SJ, Carmichael DW, Hamandi K, Guye M, Thornton R, Rodionov R, Friston KJ, Duncan JS, Lemieux L. Causal hierarchy within the thalamo-cortical network in spike and wave discharges. PLoS One 2009; 4:e6475. [PMID: 19649252 PMCID: PMC2715100 DOI: 10.1371/journal.pone.0006475] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Accepted: 06/25/2009] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Generalised spike wave (GSW) discharges are the electroencephalographic (EEG) hallmark of absence seizures, clinically characterised by a transitory interruption of ongoing activities and impaired consciousness, occurring during states of reduced awareness. Several theories have been proposed to explain the pathophysiology of GSW discharges and the role of thalamus and cortex as generators. In this work we extend the existing theories by hypothesizing a role for the precuneus, a brain region neglected in previous works on GSW generation but already known to be linked to consciousness and awareness. We analysed fMRI data using dynamic causal modelling (DCM) to investigate the effective connectivity between precuneus, thalamus and prefrontal cortex in patients with GSW discharges. METHODOLOGY AND PRINCIPAL FINDINGS We analysed fMRI data from seven patients affected by Idiopathic Generalized Epilepsy (IGE) with frequent GSW discharges and significant GSW-correlated haemodynamic signal changes in the thalamus, the prefrontal cortex and the precuneus. Using DCM we assessed their effective connectivity, i.e. which region drives another region. Three dynamic causal models were constructed: GSW was modelled as autonomous input to the thalamus (model A), ventromedial prefrontal cortex (model B), and precuneus (model C). Bayesian model comparison revealed Model C (GSW as autonomous input to precuneus), to be the best in 5 patients while model A prevailed in two cases. At the group level model C dominated and at the population-level the p value of model C was approximately 1. CONCLUSION Our results provide strong evidence that activity in the precuneus gates GSW discharges in the thalamo-(fronto) cortical network. This study is the first demonstration of a causal link between haemodynamic changes in the precuneus -- an index of awareness -- and the occurrence of pathological discharges in epilepsy.
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Affiliation(s)
- Anna E Vaudano
- Department of Neurology, Policlinico Umberto I, University of Rome La Sapienza, Rome, Italy
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12
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Hughes JR. Absence seizures: a review of recent reports with new concepts. Epilepsy Behav 2009; 15:404-12. [PMID: 19632158 DOI: 10.1016/j.yebeh.2009.06.007] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Revised: 06/02/2009] [Accepted: 06/07/2009] [Indexed: 02/01/2023]
Abstract
Absence seizures with bilateral spike-wave (SW) complexes at 3Hz are divided into the childhood form, with onset at around 6 years of age, and the juvenile form, with onset usually at 12 years of age. These seizures typically last 9-12s and, at times, are activated by hyperventilation and occasionally by photic stimulation. Generalized tonic-clonic (GTC) seizures may also occur, especially in the juvenile form. There may be cognitive changes, in addition to linguistic and behavioral problems. Possible mechanisms for epileptogenesis may involve GABAergic systems, but especially T-calcium channels. The thalamus, especially the reticular nucleus, plays a major role, as does the frontal cortex, mainly the dorsolateral and orbital frontal areas, to the extent that some investigators have concluded that absence seizures are not truly generalized, but rather have selective cortical networks, mainly ventromesial frontal areas and the somatosensory cortex. The latter network is a departure from the more popular concept of a generalized epilepsy. Between the "centrencephalic" and "corticoreticular" theories, a "unified" theory is presented. Proposed genes include T-calcium channel gene CACNA1H, likely a susceptible gene in the Chinese Han population and a contributory gene in Caucasians. Electroencephalography has revealed an interictal increase in prefrontal activity, essential for the buildup of the ictal SW complexes maximal in that region. Infraslow activity can also be seen during ictal SW complexes. For treatment, counter to common belief, ethosuximide may not increase GTC seizures, as it reduces low-threshold T-calcium currents in thalamic neurons. Valproic acid and lamotrigine are also first-line medications. In addition, zonisamide and levetiracetam can be very helpful in absence epilepsy.
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Affiliation(s)
- John R Hughes
- Department of Neurology, University of Illinois Medical Center (M/C 796), 912 South Wood Street, Chicago, IL 60612, USA.
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Chassagnon S, Hawko CS, Bernasconi A, Gotman J, Dubeau F. Coexistence of symptomatic focal and absence seizures: video-EEG and EEG-fMRI evidence of overlapping but independent epileptogenic networks. Epilepsia 2009; 50:1821-6. [PMID: 19453711 DOI: 10.1111/j.1528-1167.2009.02092.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The distinction between typical absences and hypomotor seizures in patients having frontal lesions is difficult. In focal epilepsy, generalized-like interictal discharges can reflect either a coexistent generalized epileptic trait or a secondary bilateral synchrony. Using combined measures of the EEG and blood oxygenation level dependent (BOLD) activity, we studied a 50-year-old patient with both absence-like and symptomatic focal motor seizures. Focal activity induced activation in the lesional area and deactivation in the contralateral central cortex. Generalized spike-and-wave discharges (GSWDs) resulted also in perilesional activation, and multifocal symmetrical cortical and thalamic activations, and deactivation in associative cortical areas. Although the central cortex was involved during both types of epileptic activity, electroencephalography (EEG)-functional magnetic resonance imaging (fMRI) revealed distinct neuronal networks at the time of the focal or generalized discharges, allowing a clear-cut differentiation of the generators. Whether the patient had distinct epileptic syndromes or distinct electrographic patterns from the lesional trigger remains debatable.
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Affiliation(s)
- Serge Chassagnon
- Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada
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Pulsipher DT, Seidenberg M, Guidotti L, Tuchscherer VN, Morton J, Sheth RD, Hermann B. Thalamofrontal circuitry and executive dysfunction in recent-onset juvenile myoclonic epilepsy. Epilepsia 2009; 50:1210-9. [PMID: 19183226 DOI: 10.1111/j.1528-1167.2008.01952.x] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE Thalamofrontal abnormalities have been identified in chronic primary generalized epilepsy, specifically in juvenile myoclonic epilepsy (JME). These regions also underlie executive functioning, although their relationship has yet to be examined in JME. This study examined the relationship between thalamic and frontal volumes and executive function in recent-onset JME compared to healthy control subjects and recent-onset benign childhood epilepsy with centrotemporal spikes (BCECTS), a syndrome not typically associated with thalamocortical or executive dysfunction. METHODS Twenty children with recent-onset JME were compared to 51 healthy controls and 12 children with BCECTS using quantitative magnetic resonance imaging (MRI) and measures of executive abilities. Quantitative thalamic and frontal volumes were obtained through semi-automated software. Subtests from the Delis-Kaplan Executive Function System (D-KEFS) and the Behavior Rating Inventory of Executive Function (BRIEF) were used to measure executive function. RESULTS Executive functions were impaired in JME subjects compared to control and BCECTS subjects. Subjects with JME had significantly smaller thalamic volumes and more frontal cerebrospinal fluid (CSF) than control and BCECTS subjects. Thalamic and frontal volumes were significantly related to executive functioning in the JME group, but not in the other two groups. DISCUSSION Children with JME have significant executive dysfunction associated with significantly smaller thalami and more frontal CSF. Children with recent-onset BCECTS do not display the same pattern. Frontal and thalamic volumes appear to mediate the relationship between executive functioning and brain structure in JME.
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Affiliation(s)
- Dalin T Pulsipher
- Department of Psychology, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois 60064, USA.
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Sitnikova E, van Luijtelaar G. Electroencephalographic Characterization of Spike-Wave Discharges in Cortex and Thalamus in WAG/Rij Rats. Epilepsia 2007. [DOI: 10.1111/j.1528-1167.2007.01250.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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