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Nair PP, Menon RN, Radhakrishnan A, Cherian A, Abraham M, Vilanilam G, Kesavadas C, Thomas B, Alexander A, Thomas SV. Is 'burned-out hippocampus' syndrome a distinct electro-clinical variant of MTLE-HS syndrome? Epilepsy Behav 2017; 69:53-58. [PMID: 28235654 DOI: 10.1016/j.yebeh.2017.01.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 12/28/2016] [Accepted: 01/06/2017] [Indexed: 11/30/2022]
Abstract
AIM To study the clinical, electrophysiological and imaging characteristics of patients with unilateral mesial temporal lobe epilepsy (MTLE) with contralateral ictal onset on scalp EEG, viz. 'burned-out hippocampus' syndrome (MTLE-BHS). METHODS MTLE-BHS was defined as TLE with unilateral hippocampal sclerosis (HS) without any dual pathology on MRI and contralateral ictal onset on scalp EEG, unlike in classical hippocampal sclerosis (HS). Consecutive "MTLE-BHS" patients evaluated at our Centre for Comprehensive Epilepsy Care from January 2005 to July 2014 were studied. Twenty-five cases of classic MTLE-HS operated during the same period were also analyzed for comparison. RESULTS Seventeen patients were diagnosed to have MTLE-BHS. Mean age of seizure onset was 9.5±7.7years and the mean duration of epilepsy was18.2±7.3years. Epigastric aura was more common in MTLE-HS and fear, secondary generalized seizures and temporal polar changes on MRI were more prevalent in the MTLE-BHS subgroup. In the latter group, five (29%) exhibited seizure semiology and 2 (12%) had interictal discharges discordant to the side of MTS. Eight (47%) patients in the MTLE-BHS sub-group had normal medial temporal volume on Scheltens scale. Eight patients among MTLE-BHS underwent surgery (4 following intracranial monitoring that localized to the side of HS) with Engel class I outcome at 1year follow-up in 6 and Engel class II outcome in 2. CONCLUSION Attenuation of ipsilateral fast ictal rhythms on scalp EEG as well as neocortical changes are likely to be deterministic factors for MTLE-BHS as opposed to the severity of hippocampal atrophy. Considering good post-operative outcomes, intracranial monitoring for surgical selection is not mandatory in MTLE-BHS despite discordant semiology and ictal onset, in the presence of inter-ictal, functional imaging and neuropsychology data concordant to the side of HS.
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Affiliation(s)
- Pradeep P Nair
- Dept. of Neurology, Jawaharlal Institute of Post Graduate Medical Education & Research, Puducherry 605006, India
| | - Ramshekhar N Menon
- R Madhavan Nayar Centre for Comprehensive Epilepsy Care, Department of Neurology, SreeChitraTirunal Institute for Medical Sciences and Technology, Thiruvananthapuram 695011, India.
| | - Ashalatha Radhakrishnan
- R Madhavan Nayar Centre for Comprehensive Epilepsy Care, Department of Neurology, SreeChitraTirunal Institute for Medical Sciences and Technology, Thiruvananthapuram 695011, India
| | - Ajit Cherian
- R Madhavan Nayar Centre for Comprehensive Epilepsy Care, Department of Neurology, SreeChitraTirunal Institute for Medical Sciences and Technology, Thiruvananthapuram 695011, India
| | - Mathew Abraham
- R Madhavan Nayar Centre for Comprehensive Epilepsy Care, Department of Neurology, SreeChitraTirunal Institute for Medical Sciences and Technology, Thiruvananthapuram 695011, India
| | - George Vilanilam
- R Madhavan Nayar Centre for Comprehensive Epilepsy Care, Department of Neurology, SreeChitraTirunal Institute for Medical Sciences and Technology, Thiruvananthapuram 695011, India
| | - C Kesavadas
- R Madhavan Nayar Centre for Comprehensive Epilepsy Care, Department of Neurology, SreeChitraTirunal Institute for Medical Sciences and Technology, Thiruvananthapuram 695011, India
| | - Bejoy Thomas
- R Madhavan Nayar Centre for Comprehensive Epilepsy Care, Department of Neurology, SreeChitraTirunal Institute for Medical Sciences and Technology, Thiruvananthapuram 695011, India
| | - Aley Alexander
- R Madhavan Nayar Centre for Comprehensive Epilepsy Care, Department of Neurology, SreeChitraTirunal Institute for Medical Sciences and Technology, Thiruvananthapuram 695011, India
| | - Sanjeev V Thomas
- R Madhavan Nayar Centre for Comprehensive Epilepsy Care, Department of Neurology, SreeChitraTirunal Institute for Medical Sciences and Technology, Thiruvananthapuram 695011, India
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Connell P, Bayat A, Joshi S, Koubeissi MZ. Acute and spontaneous seizure onset zones in the intraperitoneal kainic acid model. Epilepsy Behav 2017; 68:66-70. [PMID: 28109992 DOI: 10.1016/j.yebeh.2016.12.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 12/16/2016] [Accepted: 12/17/2016] [Indexed: 11/15/2022]
Abstract
OBJECTIVE Hippocampal monitoring is often used in the intraperitoneal kainic acid (KA) seizure model for detection and quantification of early ictal activity. Here, we investigated extra-hippocampal seizure onset zones (SOZs) in this model. METHODS Eight male Sprague Dawley rats implanted with depth electrodes were continuously recorded during intraperitoneal KA injections until status epilepticus (SE) was induced. Another group of four rats was monitored chronically up to two weeks after emergence of spontaneous recurrent seizures. All rats had hippocampal electrodes. Other sampled brain regions included, among others, the claustrum, piriform cortex, and orbital cortex. Seizures recorded with video-EEG were visually analyzed. RESULTS In the 58 seizures recorded during KA injections, the SOZ was extrahippocampal in 7 (12%), diffuse in 29 (50%), and hippocampal in 22 (38%). Of the 14 spontaneous seizures recorded, none were solely extrahippocampal, 10 (71%) were diffuse, and 4 (29%) were of hippocampal onset. All extra-hippocampal seizures propagated to the hippocampus within 4 to 50s (mean=14, n=7). No distinctive semiological manifestations correlated with the SOZs. SIGNIFICANCE We conclude that seizures can have multifocal SOZs in the KA model. This finding is important to consider when using this model, among other purposes, to screen for new therapies, study pharmacoresistance, or investigate comorbidities of epilepsy.
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Affiliation(s)
- Phillip Connell
- Department of Neurology, George Washington University, 2150 Pennsylvania Avenue NW, Washington, DC 20037, USA
| | - Arezou Bayat
- Department of Neurology, George Washington University, 2150 Pennsylvania Avenue NW, Washington, DC 20037, USA
| | - Sweta Joshi
- Department of Neurology, George Washington University, 2150 Pennsylvania Avenue NW, Washington, DC 20037, USA
| | - Mohamad Z Koubeissi
- Department of Neurology, George Washington University, 2150 Pennsylvania Avenue NW, Washington, DC 20037, USA.
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Gollwitzer S, Scott CA, Farrell F, Bell GS, de Tisi J, Walker MC, Wehner T, Sander JW, Hamer HM, Diehl B. The long-term course of temporal lobe epilepsy: From unilateral to bilateral interictal epileptiform discharges in repeated video-EEG monitorings. Epilepsy Behav 2017; 68:17-21. [PMID: 28109984 DOI: 10.1016/j.yebeh.2016.12.027] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 12/19/2016] [Accepted: 12/19/2016] [Indexed: 11/26/2022]
Abstract
INTRODUCTION Bilateral interictal epileptiform discharges (IED) and ictal patterns are common in temporal lobe epilepsy (TLE) and have been associated with decreased chances of seizure freedom after epilepsy surgery. It is unclear whether secondary epileptogenesis, although demonstrated in experimental models, exists in humans and may account for progression of epilepsy. MATERIAL AND METHODS We reviewed consecutive video-EEG recordings from 1992 to 2014 repeated at least two years apart (mean interval 6.14years) in 100 people diagnosed with TLE. RESULTS Ictal EEG patterns and IED remained restricted to one hemisphere in 36 people (group 1), 46 exhibited bilateral abnormalities from the first recording (group 2), 18 progressed from unilateral to bilateral EEG pathology over time (group 3). No significant differences between the three groups were seen with respect to age at epilepsy onset, duration, or underlying pathology. Extra-temporal IED during the first EEG recording were associated with an increased risk of developing bilateral epileptiform changes over time (hazard ratio 3.67; 95% CI 1.4, 9.4). CONCLUSION Our findings provide some support of progression in TLE and raise the possibility of secondary epileptogenesis in humans. The development of an independent contra-lateral epileptogenic focus is known to be associated with a less favorable surgical outcome. We defined reliable EEG markers for an increased risk of progression to more widespread or independent bitemporal epileptogenicity at an early stage, thus allowing for individualized pre-surgical counselling.
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Affiliation(s)
- Stephanie Gollwitzer
- NIHR University College London Hospitals Biomedical Research Centre, UCL Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom; Epilepsy Center, Department of Neurology, University Hospital Erlangen, Erlangen, Germany.
| | - Catherine A Scott
- NIHR University College London Hospitals Biomedical Research Centre, UCL Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom
| | - Fiona Farrell
- NIHR University College London Hospitals Biomedical Research Centre, UCL Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom; Epilepsy Society, Chalfont St Peter SL9 0RJ, United Kingdom
| | - Gail S Bell
- NIHR University College London Hospitals Biomedical Research Centre, UCL Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom; Epilepsy Society, Chalfont St Peter SL9 0RJ, United Kingdom
| | - Jane de Tisi
- NIHR University College London Hospitals Biomedical Research Centre, UCL Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom
| | - Matthew C Walker
- NIHR University College London Hospitals Biomedical Research Centre, UCL Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom
| | - Tim Wehner
- NIHR University College London Hospitals Biomedical Research Centre, UCL Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom
| | - Josemir W Sander
- NIHR University College London Hospitals Biomedical Research Centre, UCL Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom; Epilepsy Society, Chalfont St Peter SL9 0RJ, United Kingdom; Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, The Netherlands
| | - Hajo M Hamer
- Epilepsy Center, Department of Neurology, University Hospital Erlangen, Erlangen, Germany
| | - Beate Diehl
- NIHR University College London Hospitals Biomedical Research Centre, UCL Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom
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Hippocampal atrophy on MRI is predictive of histopathological patterns and surgical prognosis in mesial temporal lobe epilepsy with hippocampal sclerosis. Epilepsy Res 2016; 128:169-175. [DOI: 10.1016/j.eplepsyres.2016.10.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 10/04/2016] [Accepted: 10/24/2016] [Indexed: 01/19/2023]
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Abstract
SummaryIntroduction.Medial temporal lobe epilepsy (MTLE) is the most frequent form of epilepsy in adulthood. It is classified as local/regional epilepsy. However, there is increasing evidence of the involvement of both temporal lobes and this provides abundant arguments to question this view, and consider MTLE as one of the typical bilateral system epilepsies.Aim.To provide a contemporary review of medial temporal lobe epilepsy, discussing the bilateral aspects, with reference to epilepsy surgery.Methods.A literature review and a resume of the author’s own experiences with MTLE patients.Results.Recent electrophysiological and neuroimaging data provide convincing data supporting that MTLE is a bilateral disease. The uni-and bilateral features form a continuum and the participation rate of the two temporal lobes determine course and surgical perspective of the individual patient.Conclusions.The contradictory data of invasive presurgical evaluations of MTLE patients suggest that there need to identify further indicatory markers of bilaterality and thus change the presurgical evaluation from the non-invasive towards the invasive ways. The mechanisms of the interrelationship between the two temporal lobes in MTLE warrants further research.
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Schiecke K, Pester B, Piper D, Benninger F, Feucht M, Leistritz L, Witte H. Nonlinear Directed Interactions Between HRV and EEG Activity in Children With TLE. IEEE Trans Biomed Eng 2016; 63:2497-2504. [DOI: 10.1109/tbme.2016.2579021] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Comparative Lateralizing Ability of Multimodality MRI in Temporal Lobe Epilepsy. DISEASE MARKERS 2016; 2016:5923243. [PMID: 27974864 PMCID: PMC5126436 DOI: 10.1155/2016/5923243] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 09/27/2016] [Accepted: 10/20/2016] [Indexed: 11/25/2022]
Abstract
Purpose. The objective is to compare lateralizing ability of three quantitative MR (qMRI) modalities to depict changes of hippocampal architecture with clinical entities in temporal lobe epilepsy. Methods. We evaluated 14 patients with clinical and EEG proven diagnosis of unilateral TLE and 15 healthy volunteers. T1-weighted 3D dataset for volumetry, single-voxel 1H MR spectroscopy (MRS), and diffusion tensor imaging (DTI) were performed for bilateral hippocampi of all subjects. Results. Individual volumetric measurements provided accurate lateralization in 85% of the patients, spectroscopy in 57%, and DTI in 57%. Higher lateralization ratios were acquired combining volumetry-spectroscopy (85%), spectroscopy-DTI (85%), and volumetry-DTI (100%). Significantly decreased NAA/(Cho+Cr) ratios (p = 0.002) and increased FA (p = 0.001) values were obtained in ipsilateral to epileptogenic hippocampus. Duration of epilepsy and FA values showed a significant negative correlation (p = 0.016, r = −0.847). The history of febrile convulsion associated with ipsilateral increased ADC values (p = 0.015, r = 0.851) and reduced NAA/(Cho+Cr) ratios (p = 0.047, r = −761). Conclusion. Volumetry, MRS, and DTI studies provide complementary information of hippocampal pathology. For lateralization of epileptogenic focus and preoperative examination, volumetry-DTI combination may be indicative of diagnostic accuracy.
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Tsai MH, Vaughan DN, Perchyonok Y, Fitt GJ, Scheffer IE, Berkovic SF, Jackson GD. Hippocampal malrotation is an anatomic variant and has no clinical significance in MRI-negative temporal lobe epilepsy. Epilepsia 2016; 57:1719-1728. [DOI: 10.1111/epi.13505] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/25/2016] [Indexed: 11/28/2022]
Affiliation(s)
- Meng-Han Tsai
- Department of Medicine; Epilepsy Research Centre; Austin Health; University of Melbourne; Heidelberg Victoria Australia
- Department of Neurology; Kaohsiung Chang Gung Memorial Hospital; Kaohsiung Taiwan
- Department of Nursing; Meiho University; Pingtung Taiwan
| | - David N. Vaughan
- Department of Neurology; Austin Health; Florey Institute of Neuroscience and Mental Health; Melbourne Victoria Australia
| | - Yuliya Perchyonok
- Department of Radiology; Austin Hospital; Melbourne Victoria Australia
| | - Greg J. Fitt
- Department of Radiology; Austin Hospital; Melbourne Victoria Australia
| | - Ingrid E. Scheffer
- Department of Medicine; Epilepsy Research Centre; Austin Health; University of Melbourne; Heidelberg Victoria Australia
- Department of Neurology; Austin Health; Florey Institute of Neuroscience and Mental Health; Melbourne Victoria Australia
- Department of Paediatrics; Royal Children's Hospital; University of Melbourne; Melbourne Victoria Australia
| | - Samuel F. Berkovic
- Department of Medicine; Epilepsy Research Centre; Austin Health; University of Melbourne; Heidelberg Victoria Australia
- Department of Radiology; Austin Hospital; Melbourne Victoria Australia
| | - Graeme D. Jackson
- Department of Neurology; Austin Health; Florey Institute of Neuroscience and Mental Health; Melbourne Victoria Australia
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Souirti Z, Sghir A, Belfkih R, Messouak O. Focal drug-resistant epilepsy: Progress in care and barriers, a Morroccan perspective. J Clin Neurosci 2016; 34:276-280. [PMID: 27566950 DOI: 10.1016/j.jocn.2016.08.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 08/01/2016] [Indexed: 11/26/2022]
Abstract
INTRODUCTION The aim of this study is to determine the clinical, paraclinical, therapeutic and outcome aspects of drug resistant patients with epilepsy in our region and consequently to discuss methods that may improve the management of these patients. PATIENTS AND METHODS This paper presents a retrospective study of 25 adult patients that were followed for focal drug resistant epilepsy in epileptology unit of the University Hospital of Fez, Morocco. RESULTS This study recorded 25 patients including 48% of males and 52% of females. The mean age of patients was 24years-old. Hippocampal sclerosis was present in 28.5% of patients (7 cases); brain malformations were found in 19% of patients (5 cases); tumors were found in 24% of patients (6 cases); post-traumatic, post-surgical and anoxic-ischemic lesions were found in 28.5% of patients (7 cases). Resective epilepsy surgery was performed in 28,5% of patients (7 cases). Post surgical outcome was good for 5/7 patients (Engel I and II). CONCLUSION The clinical characteristics, etiologies and clinical course of medically refractory focal epilepsy in our region are similar to that reported in the global literature. We also demonstrated a long delay between onset of seizures and surgery (15years range 8-34years) and barriers to epilepsy surgery.
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Affiliation(s)
- Zouhayr Souirti
- Department of Neurology, University Hospital of Fez, Morocco; Clinical Neuroscience Laboratory, Faculty of Medicine, University of Fez, Morocco; Sleep Medicine Center, University Hospital of Fez, Morocco.
| | - Ahmed Sghir
- Department of Neurology, University Hospital of Fez, Morocco
| | - Rachid Belfkih
- Department of Neurology, University Hospital of Fez, Morocco
| | - Ouafae Messouak
- Department of Neurology, University Hospital of Fez, Morocco; Clinical Neuroscience Laboratory, Faculty of Medicine, University of Fez, Morocco
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Gupta A. Normal, Variant, Funny Looking or Atypical Hippocampus: What Does It Have to Do With Epilepsy? Epilepsy Curr 2016; 16:251-3. [PMID: 27582665 PMCID: PMC4988072 DOI: 10.5698/1535-7511-16.4.251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Davis MC, Broadwater DR, Mathews WH, Paige AL, DeWolfe JL, Elgavish RA, Riley KO, Ver Hoef LW. Statistical modeling of ICEEG features that determine resection planning. Clin Neurol Neurosurg 2016; 147:18-23. [PMID: 27249656 DOI: 10.1016/j.clineuro.2016.05.017] [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: 07/28/2015] [Revised: 02/18/2016] [Accepted: 05/16/2016] [Indexed: 11/26/2022]
Abstract
OBJECT The interpretation of intracranial EEG (ICEEG) recordings is a complex balance of the significance of specific rhythms and their relative timing to seizure onset. Ictal and interictal findings are evaluated in light of findings from cortical stimulation of eloquent cortex to determine the area of resection. PATIENTS AND METHODS Patients with ICEEG electrodes and subsequent surgical resection were retrospectively identified. Only the first 15s of ictal activity, which was divided into five 3-s epochs, was considered. Every electrode in each patient was considered a separate observation in a logistic regression model to predict whether the cortex under a given electrode was included in the planned resection. RESULTS 19 included patients had a total of 37 unique seizures. Recordings from a total of 1306 electrodes were analyzed. The strongest predictors of resection of cortex underlying a given electrode was the presence of low-voltage fast activity in Epoch 1, rhythmic spikes in Epoch 1, interictal paroxysmal fast activity, and low-voltage fast activity in Epoch 2. High-amplitude beta spikes and rhythmic slow waves were also significant predictors in Epoch 1. Interictal spikes had a higher odds ratio of affecting the planned resection if described as "continuous" or "very frequent". The presence of motor or language cortex were the strongest negative predictors of resecting underlying cortex. CONCLUSIONS Here we describe a novel model of ictal and interictal patterns significantly associated with the inclusion of cortex underlying a given ICEEG electrode in the surgical resection plan.
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Affiliation(s)
- Matthew C Davis
- Department of Neurosurgery, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Devin R Broadwater
- University of Alabama at Birmingham School of Medical, Birmingham, AL, United States.
| | - Winn H Mathews
- School of Medicine, University of South Alabama, Mobile, AL, United States
| | - A Lebron Paige
- UAB Epilepsy Center, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Jennifer L DeWolfe
- UAB Epilepsy Center, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Ro A Elgavish
- UAB Epilepsy Center, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Kristen O Riley
- Department of Neurosurgery, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Lawrence W Ver Hoef
- UAB Epilepsy Center, University of Alabama at Birmingham, Birmingham, AL, United States
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Griguoli M, Sgritta M, Cherubini E. Presynaptic BK channels control transmitter release: physiological relevance and potential therapeutic implications. J Physiol 2016; 594:3489-500. [PMID: 26969302 DOI: 10.1113/jp271841] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 03/02/2016] [Indexed: 12/14/2022] Open
Abstract
BK channels are large conductance potassium channels characterized by four pore-forming α subunits, often co-assembled with auxiliary β and γ subunits to regulate Ca(2+) sensitivity, voltage dependence and gating properties. Abundantly expressed in the CNS, they have the peculiar characteristic of being activated by both voltage and intracellular calcium rise. The increase in intracellular calcium via voltage-dependent calcium channels (Cav ) during spiking triggers conformational changes and BK channel opening. This narrows the action potential and induces a fast after-hyperpolarization that shuts calcium channels. The tight coupling between BK and Cav channels at presynaptic active zones makes them particularly suitable for regulating calcium entry and neurotransmitter release. While in most synapses, BK channels exert a negative control on transmitter release under basal conditions, in others they do so only under pathological conditions, serving as an emergency brake to protect against hyperactivity. In particular cases, by interacting with other channels (i.e. limiting the activation of the delayed rectifier and the inactivation of Na(+) channels), BK channels induce spike shortening, increase in firing rate and transmitter release. Changes in transmitter release following BK channel dysfunction have been implicated in several neurological disorders including epilepsy, schizophrenia, fragile X syndrome, mental retardation and autism. In particular, two mutations, one in the α and one in the β3 subunit, resulting in a gain of function have been associated with epilepsy. Hence, these discoveries have allowed identification of BK channels as new drug targets for therapeutic intervention.
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Affiliation(s)
- Marilena Griguoli
- European Brain Research Institute (EBRI) 'Fondazione Rita Levi-Montalcini', Via del Fosso di Fiorano 64, 00143, Rome, Italy
| | - Martina Sgritta
- European Brain Research Institute (EBRI) 'Fondazione Rita Levi-Montalcini', Via del Fosso di Fiorano 64, 00143, Rome, Italy
| | - Enrico Cherubini
- European Brain Research Institute (EBRI) 'Fondazione Rita Levi-Montalcini', Via del Fosso di Fiorano 64, 00143, Rome, Italy.,International School for Advanced Studies (SISSA), Trieste, Italy
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Hippocampal Malrotation Is Associated With Prolonged Febrile Seizures: Results of the FEBSTAT Study. AJR Am J Roentgenol 2016; 205:1068-74. [PMID: 26496555 DOI: 10.2214/ajr.14.13330] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
OBJECTIVE Hippocampal malrotation is characterized by incomplete hippocampal inversion with a rounded shape and blurred internal architecture. There is still debate about whether hippocampal malrotation has pathologic significance. We present findings from the Consequences of Prolonged Febrile Seizures in Childhood (FEBSTAT) study on the frequency of and risk factors for hippocampal malrotation. SUBJECTS AND METHODS FEBSTAT is a prospective multicenter study investigating the consequences of febrile status epilepticus in childhood. MRI studies of 226 patients with febrile status epilepticus were analyzed visually by two board-certified neuroradiologists blinded to clinical details and were compared with MRI studies of 96 subjects with first simple febrile seizure. Quantitative analysis of hippocampal volume was performed by two independent observers. RESULTS Hippocampal malrotation was present in 20 of 226 (8.8%) patients with febrile status epilepticus compared with two of 96 (2.1%) control subjects (odds ratio [OR], 4.56; 95% CI, 1.05-19.92). Hippocampal malrotation was exclusively left-sided in 18 of 22 (81.8%) patients and bilateral in the remaining four patients (18.2%). There was no case of exclusively right-sided hippocampal malrotation. Hippocampal malrotation was more common in boys than in girls (OR, 6.1; 95% CI, 1.7-21.5). On quantitative volumetric MRI analysis, the left hippocampal volume was smaller in patients with hippocampal malrotation than in control subjects with simple febrile seizure (p = 0.004), and the right-to-left hippocampal volume ratio was higher in the hippocampal malrotation group than in the simple febrile seizure group (p < 0.001). CONCLUSION Hippocampal malrotation is a developmental malformation that predominantly affects the left hippocampus in male patients and is more frequently found in children with prolonged febrile status epilepticus than in control subjects. These data provide further evidence that hippocampal malrotation represents a pathologic error in brain development rather than a normal variant.
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Memarian N, Kim S, Dewar S, Engel J, Staba RJ. Multimodal data and machine learning for surgery outcome prediction in complicated cases of mesial temporal lobe epilepsy. Comput Biol Med 2015; 64:67-78. [PMID: 26149291 PMCID: PMC4554822 DOI: 10.1016/j.compbiomed.2015.06.008] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 06/04/2015] [Accepted: 06/10/2015] [Indexed: 11/21/2022]
Abstract
BACKGROUND This study sought to predict postsurgical seizure freedom from pre-operative diagnostic test results and clinical information using a rapid automated approach, based on supervised learning methods in patients with drug-resistant focal seizures suspected to begin in temporal lobe. METHOD We applied machine learning, specifically a combination of mutual information-based feature selection and supervised learning classifiers on multimodal data, to predict surgery outcome retrospectively in 20 presurgical patients (13 female; mean age±SD, in years 33±9.7 for females, and 35.3±9.4 for males) who were diagnosed with mesial temporal lobe epilepsy (MTLE) and subsequently underwent standard anteromesial temporal lobectomy. The main advantage of the present work over previous studies is the inclusion of the extent of ipsilateral neocortical gray matter atrophy and spatiotemporal properties of depth electrode-recorded seizures as training features for individual patient surgery planning. RESULTS A maximum relevance minimum redundancy (mRMR) feature selector identified the following features as the most informative predictors of postsurgical seizure freedom in this study's sample of patients: family history of epilepsy, ictal EEG onset pattern (positive correlation with seizure freedom), MRI-based gray matter thickness reduction in the hemisphere ipsilateral to seizure onset, proportion of seizures that first appeared in ipsilateral amygdala to total seizures, age, epilepsy duration, delay in the spread of ipsilateral ictal discharges from site of onset, gender, and number of electrode contacts at seizure onset (negative correlation with seizure freedom). Using these features in combination with a least square support vector machine (LS-SVM) classifier compared to other commonly used classifiers resulted in very high surgical outcome prediction accuracy (95%). CONCLUSIONS Supervised machine learning using multimodal compared to unimodal data accurately predicted postsurgical outcome in patients with atypical MTLE.
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Affiliation(s)
- Negar Memarian
- Department of Psychology, David Geffen School of Medicine and at UCLA, Los Angeles, CA 90095, United States; Department of Neurology, David Geffen School of Medicine and at UCLA, Los Angeles, CA 90095, United States.
| | - Sally Kim
- Department of Neurology, David Geffen School of Medicine and at UCLA, Los Angeles, CA 90095, United States
| | - Sandra Dewar
- Department of Neurosurgery, David Geffen School of Medicine and at UCLA, Los Angeles, CA 90095, United States
| | - Jerome Engel
- Department of Neurology, David Geffen School of Medicine and at UCLA, Los Angeles, CA 90095, United States; Department of Neurosurgery, David Geffen School of Medicine and at UCLA, Los Angeles, CA 90095, United States; Department of Neurobiology, David Geffen School of Medicine and at UCLA, Los Angeles, CA 90095, United States; Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine and at UCLA, Los Angeles, CA 90095, United States
| | - Richard J Staba
- Department of Neurology, David Geffen School of Medicine and at UCLA, Los Angeles, CA 90095, United States
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Dupont S, Samson Y, Nguyen-Michel VH, Zavanone C, Clémenceau S, Miles R, Baulac M, Adam C. Are auras a reliable clinical indicator in medial temporal lobe epilepsy with hippocampal sclerosis? Eur J Neurol 2015; 22:1310-6. [DOI: 10.1111/ene.12747] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 03/30/2015] [Indexed: 11/28/2022]
Affiliation(s)
- S. Dupont
- Epilepsy Unit; Hôpital de la Pitié-Salpêtrière, APHP; Paris France
- Rehabilitation Unit; Hôpital de la Pitié-Salpêtrière, APHP; Paris France
- Inserm U 1127; CNRS UMR 7225; UPMC Univ Paris 06 UMR S 1127; Institut du Cerveau et de la Moelle épinière; ICM; Sorbonne Universités; Paris France
| | - Y. Samson
- Inserm U 1127; CNRS UMR 7225; UPMC Univ Paris 06 UMR S 1127; Institut du Cerveau et de la Moelle épinière; ICM; Sorbonne Universités; Paris France
- Stroke Unit; Hôpital de la Pitié-Salpêtrière, APHP; Paris France
| | - V.-H. Nguyen-Michel
- Epilepsy Unit; Hôpital de la Pitié-Salpêtrière, APHP; Paris France
- Neurophysiology Unit of the Charles Foix Hospital, APHP; Paris France
| | - C. Zavanone
- Rehabilitation Unit; Hôpital de la Pitié-Salpêtrière, APHP; Paris France
| | - S. Clémenceau
- Epilepsy Unit; Hôpital de la Pitié-Salpêtrière, APHP; Paris France
- Inserm U 1127; CNRS UMR 7225; UPMC Univ Paris 06 UMR S 1127; Institut du Cerveau et de la Moelle épinière; ICM; Sorbonne Universités; Paris France
- Neurosurgery Unit; Hôpital de la Pitié-Salpêtrière, APHP; Paris France
| | - R. Miles
- Inserm U 1127; CNRS UMR 7225; UPMC Univ Paris 06 UMR S 1127; Institut du Cerveau et de la Moelle épinière; ICM; Sorbonne Universités; Paris France
| | - M. Baulac
- Epilepsy Unit; Hôpital de la Pitié-Salpêtrière, APHP; Paris France
- Inserm U 1127; CNRS UMR 7225; UPMC Univ Paris 06 UMR S 1127; Institut du Cerveau et de la Moelle épinière; ICM; Sorbonne Universités; Paris France
| | - C. Adam
- Epilepsy Unit; Hôpital de la Pitié-Salpêtrière, APHP; Paris France
- Inserm U 1127; CNRS UMR 7225; UPMC Univ Paris 06 UMR S 1127; Institut du Cerveau et de la Moelle épinière; ICM; Sorbonne Universités; Paris France
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66
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Temporopolar blurring in temporal lobe epilepsy with hippocampal sclerosis and long-term prognosis after epilepsy surgery. Epilepsy Res 2015; 112:76-83. [DOI: 10.1016/j.eplepsyres.2015.02.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 02/14/2015] [Accepted: 02/17/2015] [Indexed: 11/20/2022]
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67
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MTLE with hippocampal sclerosis in adult as a syndrome. Rev Neurol (Paris) 2015; 171:259-66. [DOI: 10.1016/j.neurol.2015.02.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 02/03/2015] [Indexed: 11/19/2022]
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Řehulka P, Doležalová I, Janoušová E, Tomášek M, Marusič P, Brázdil M, Kuba R. Ictal and postictal semiology in patients with bilateral temporal lobe epilepsy. Epilepsy Behav 2014; 41:40-6. [PMID: 25282104 DOI: 10.1016/j.yebeh.2014.09.033] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 09/07/2014] [Accepted: 09/10/2014] [Indexed: 11/28/2022]
Abstract
Bilateral temporal lobe epilepsy is characterized by evidence of seizure onset independently in both temporal lobes. The main aim of the present study was to determine whether patients with evidence of independent bilateral temporal lobe epilepsy (biTLE) can be identified noninvasively on the basis of seizure semiology analysis. Thirteen patients with biTLE, as defined by invasive EEG, were matched with 13 patients with unilateral temporal lobe epilepsy (uniTLE). In all 26 patients, the frequency of predefined clusters of ictal and periictal signs were evaluated: ictal motor signs (IMSs), periictal motor signs (PIMSs), periictal vegetative signs (PIVSs), the frequency of early oroalimentary automatisms (EOAs), and the duration of postictal unresponsiveness (PU). Some other noninvasive and clinical data were also evaluated. A lower frequency of IMSs was noted in the group with biTLE (patients = 46.2%, seizures = 20.7%) than in the group with uniTLE (patients = 92.3%, seizures = 61.0%) (p = 0.030; p < 0.001, respectively). The individual IMS average per seizure was significantly lower in the group with biTLE (0.14; range = 0-1.0) than in the group with uniTLE (0.80; range = 0-2.6) (p = 0.003). Postictal unresponsiveness was longer than 5 min in more patients (75.0%) and seizures (42.9%) in the group with biTLE than in the group with uniTLE (patients = 30.8%, seizures = 18.6%) (p = 0.047; p = 0.002). The frequency of EOAs, PIMSs, PIVSs, and other clinical data did not differ significantly. There is a lower frequency of ictal motor signs and longer duration of postictal unresponsiveness in patients with biTLE.
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Affiliation(s)
- Pavel Řehulka
- Brno Epilepsy Center, First Department of Neurology, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic; Behavioural and Social Neuroscience Research Group, Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic.
| | - Irena Doležalová
- Brno Epilepsy Center, First Department of Neurology, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic; Behavioural and Social Neuroscience Research Group, Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic
| | - Eva Janoušová
- Institute of Biostatistics and Analyses, Masaryk University, Brno, Czech Republic
| | - Martin Tomášek
- Department of Neurology, Charles University in Prague, Second Faculty of Medicine, Motol University Hospital, Prague, Czech Republic
| | - Petr Marusič
- Department of Neurology, Charles University in Prague, Second Faculty of Medicine, Motol University Hospital, Prague, Czech Republic
| | - Milan Brázdil
- Brno Epilepsy Center, First Department of Neurology, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic; Behavioural and Social Neuroscience Research Group, Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic
| | - Robert Kuba
- Brno Epilepsy Center, First Department of Neurology, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic; Behavioural and Social Neuroscience Research Group, Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic
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69
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Vogt VL, Witt JA, Malter MP, Schoene-Bake JC, Lehe MV, Elger CE, Helmstaedter C. Neuropsychological outcome after epilepsy surgery in patients with bilateral Ammon's horn sclerosis. J Neurosurg 2014; 121:1247-56. [DOI: 10.3171/2014.7.jns132037] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
The purpose of this study was to retrospectively assess the objective and subjective neuropsychological outcome after epilepsy surgery in patients with bilateral Ammon's horn sclerosis (AHS).
Methods
Memory and executive functions were evaluated at baseline and at follow-up in 11 surgically treated patients and compared with 8 pharmacologically treated patients with temporal lobe epilepsy and bilateral AHS. The median follow-up duration was 16 months in the surgically treated patients and 80.5 months in the pharmacologically treated group. Subjective outcome was evaluated by questionnaires and included mood, quality of life, subjective memory, and activities of daily living.
Results
At the follow-up assessment, 82% of the surgically treated patients as opposed to 0% of the nonsurgery patients were seizure free. In the surgical group, nonverbal memory performance did not change significantly in any patient after surgery, but there was a floor effect in 55% of the surgical patients. Regarding verbal memory, 9% of the surgical patients improved while 73% declined, despite severe impairments already evident at baseline. In the nonsurgery control group, 13% of the patients declined in nonverbal memory (floor effect in 63%) and 25% declined in verbal memory (floor effect in 25%) at follow-up. None of the controls improved at follow-up. Executive functions remained unchanged on an impaired level in both groups. At follow-up, the patient groups did not differ significantly with respect to mood, quality of life, subjective memory, or activities of daily living. However, in most aspects, surgically treated patients reported a slightly better subjective outcome than pharmacologically treated patients and a significantly improved quality of life.
Conclusions
These results suggest that beyond benefits concerning seizure control, surgically treated patients with bilateral AHS, despite already poor baseline performance, are still at risk for severe postoperative decline in memory. In the light of predominantly minor benefits on a subjective level, the findings put the overall outcome of epilepsy surgery in bilateral AHS patients into perspective.
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Affiliation(s)
| | | | | | | | - Marec von Lehe
- 2Neurosurgery, University of Bonn, Medical Center, Bonn, Germany
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Landazuri P. Mesial temporal lobe epilepsy: a distinct electroclinical subtype of temporal lobe epilepsy. Neurodiagn J 2014; 54:274-88. [PMID: 25351035 DOI: 10.1080/21646821.2014.11106809] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Mesial temporal lobe epilepsy is a common subtype of temporal lobe epilepsy. Its most common cause is hippocampal sclerosis, which contributes to its distinct electroclinical phenotype that is seen commonly in the epilepsy monitoring unit setting. The common electrophysiological data show anterior temporal interictal sharp waves as well as rhythmic theta activity in the same localization. While the electrophysiological data can at times be misleading, its stereotyped and characteristic semiology can often allow for accurate diagnosis on its own. As patients with mesial temporal lobe epilepsy often fail medical therapy, surgical therapy can be considered. Early accurate diagnosis in these patients is essential for optimal care.
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Restrepo D, Hellier JL, Salcedo E. Complex metabolically demanding sensory processing in the olfactory system: implications for epilepsy. Epilepsy Behav 2014; 38:37-42. [PMID: 24113565 PMCID: PMC3979506 DOI: 10.1016/j.yebeh.2013.08.036] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 08/26/2013] [Indexed: 12/23/2022]
Abstract
Although the olfactory system is not generally associated with seizures, sharp application of odor eliciting activity in a large number of olfactory sensory neurons (OSNs) has been shown to elicit seizures. This is most likely due to increased ictal activity in the anterior piriform cortex-an area of the olfactory system that has limited GABAergic interneuron inhibition of pyramidal output cell activity. Such hyperexcitability in a well-characterized and highly accessible system makes olfaction a potentially powerful model system to examine epileptogenesis.
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Affiliation(s)
- Diego Restrepo
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Center for Neuroscience, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Rocky Mountain Taste and Smell Center, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA.
| | - Jennifer L. Hellier
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045,Rocky Mountain Taste and Smell Center, University of Colorado Anschutz Medical Campus, Aurora, CO 80045,Department of Family Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Ernesto Salcedo
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045,Rocky Mountain Taste and Smell Center, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
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Hamelin S, Pouyatos B, Khalaf-Nazzal R, Chabrol T, Francis F, David O, Depaulis A. Long-term modifications of epileptogenesis and hippocampal rhythms after prolonged hyperthermic seizures in the mouse. Neurobiol Dis 2014; 69:156-68. [DOI: 10.1016/j.nbd.2014.05.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 04/08/2014] [Accepted: 05/17/2014] [Indexed: 01/15/2023] Open
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Does the region of epileptogenicity influence the pattern of change in cortical excitability? Clin Neurophysiol 2014; 126:249-56. [PMID: 25002368 DOI: 10.1016/j.clinph.2014.05.029] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Revised: 05/11/2014] [Accepted: 05/14/2014] [Indexed: 11/21/2022]
Abstract
OBJECTIVE To investigate whether cortical excitability measures on transcranial magnetic stimulation (TMS) differed between groups of patients with different focal epilepsy syndromes. METHODS 85 Patients with focal epilepsy syndromes divided into temporal and extra-temporal lobe epilepsy were studied. The cohorts were further divided into drug naïve-new onset, refractory and seizure free groups. Motor threshold (MT) and paired pulse TMS at short (2, 5, 10, 15 ms) and long (100-300 ms) interstimulus intervals (ISIs) were measured. Results were compared to those of 20 controls. RESULTS Cortical excitability was higher at 2 & 5 ms and 250, 300 ms ISIs (p<0.01) in focal epilepsy syndromes compared to controls however significant inter-hemispheric differences in MT and the same ISIs were only seen in the drug naïve state early at onset and were much more prominent in temporal lobe epilepsy. CONCLUSION Disturbances in cortical excitability are more confined to the affected hemisphere in temporal lobe epilepsy but only early at onset in the drug naïve state. SIGNIFICANCE Group TMS studies show that cortical excitability measures are different in temporal lobe epilepsy and can be distinguished from other focal epilepsies early at onset in the drug naïve state. Further studies are needed to determine whether these results can be applied clinically as the utility of TMS in distinguishing between epilepsy syndromes at an individual level remains to be determined.
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74
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Graph theory findings in the pathophysiology of temporal lobe epilepsy. Clin Neurophysiol 2014; 125:1295-305. [PMID: 24831083 DOI: 10.1016/j.clinph.2014.04.004] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 04/08/2014] [Accepted: 04/10/2014] [Indexed: 01/26/2023]
Abstract
Temporal lobe epilepsy (TLE) is the most common form of adult epilepsy. Accumulating evidence has shown that TLE is a disorder of abnormal epileptogenic networks, rather than focal sources. Graph theory allows for a network-based representation of TLE brain networks, and has potential to illuminate characteristics of brain topology conducive to TLE pathophysiology, including seizure initiation and spread. We review basic concepts which we believe will prove helpful in interpreting results rapidly emerging from graph theory research in TLE. In addition, we summarize the current state of graph theory findings in TLE as they pertain its pathophysiology. Several common findings have emerged from the many modalities which have been used to study TLE using graph theory, including structural MRI, diffusion tensor imaging, surface EEG, intracranial EEG, magnetoencephalography, functional MRI, cell cultures, simulated models, and mouse models, involving increased regularity of the interictal network configuration, altered local segregation and global integration of the TLE network, and network reorganization of temporal lobe and limbic structures. As different modalities provide different views of the same phenomenon, future studies integrating data from multiple modalities are needed to clarify findings and contribute to the formation of a coherent theory on the pathophysiology of TLE.
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75
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Involvement of thalamus in initiation of epileptic seizures induced by pilocarpine in mice. Neural Plast 2014; 2014:675128. [PMID: 24778885 PMCID: PMC3981117 DOI: 10.1155/2014/675128] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Accepted: 02/05/2014] [Indexed: 01/31/2023] Open
Abstract
Studies have suggested that thalamus is involved in temporal lobe epilepsy, but the role of thalamus is still unclear. We obtained local filed potentials (LFPs) and single-unit activities from CA1 of hippocampus and parafascicular nucleus of thalamus during the development of epileptic seizures induced by pilocarpine in mice. Two measures, redundancy and directionality index, were used to analyze the electrophysiological characters of neuronal activities and the information flow between thalamus and hippocampus. We found that LFPs became more regular during the seizure in both hippocampus and thalamus, and in some cases LFPs showed a transient disorder at seizure onset. The variation tendency of the peak values of cross-correlation function between neurons matched the variation tendency of the redundancy of LFPs. The information tended to flow from thalamus to hippocampus during seizure initiation period no matter what the information flow direction was before the seizure. In some cases the information flow was symmetrically bidirectional, but none was found in which the information flowed from hippocampus to thalamus during the seizure initiation period. In addition, inactivation of thalamus by tetrodotoxin (TTX) resulted in a suppression of seizures. These results suggest that thalamus may play an important role in the initiation of epileptic seizures.
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Sànchez J, Centanaro M, Solís J, Delgado F, Yépez L. Factors predicting the outcome following medical treatment of mesial temporal epilepsy with hippocampal sclerosis. Seizure 2014; 23:448-53. [PMID: 24680551 DOI: 10.1016/j.seizure.2014.03.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 03/01/2014] [Accepted: 03/04/2014] [Indexed: 10/25/2022] Open
Abstract
PURPOSE There is a lack of information from South America regarding factors that predict the clinical outcomes of patients treated medically for mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS). This study was conducted to determine which of these factors are the most important. METHODS This study included 110 South American patients with MTLE-HS treated with antiepileptic drugs. The factors considered included age, gender, age of epilepsy onset, interval between the lesion and the first seizure, central nervous system infection, traumatic brain injury, perinatal asphyxia, febrile convulsion, history of status epilepticus, types of seizures, site of hippocampal sclerosis (HS), extrahippocampal pathology, and electroencephalogram (EEG) abnormalities. The patients were divided into two groups based on the response to treatment: Group I, seizure free for at least two years; and Group II, not seizure free. RESULTS On the multivariate analysis, the factors associated with a poor prognosis in terms of seizure frequency and control following treatment included the presence of an early onset of seizure, more than 10 seizures per month before treatment, and EEG abnormalities. CONCLUSION The recognition of risk factors, such as early onset of seizures, more than 10 seizures per month before treatment, and EEG abnormalities, could lead to the identification of risk groups among patients with MTLE-HS and refractory epilepsy, possibly designating these individuals as candidates for early epilepsy surgery.
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Affiliation(s)
- Javier Sànchez
- Brain Research Centre, Institute of Neurosciences, Guayaquil Welfare Board, Guayaquil, Ecuador.
| | - Mirella Centanaro
- Brain Research Centre, Institute of Neurosciences, Guayaquil Welfare Board, Guayaquil, Ecuador
| | - Juanita Solís
- Brain Research Centre, Institute of Neurosciences, Guayaquil Welfare Board, Guayaquil, Ecuador
| | - Fabrizio Delgado
- Brain Research Centre, Institute of Neurosciences, Guayaquil Welfare Board, Guayaquil, Ecuador
| | - Luis Yépez
- Brain Research Centre, Institute of Neurosciences, Guayaquil Welfare Board, Guayaquil, Ecuador
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Expression of HIF-1α and MDR1/P-glycoprotein in refractory mesial temporal lobe epilepsy patients and pharmacoresistant temporal lobe epilepsy rat model kindled by coriaria lactone. Neurol Sci 2014; 35:1203-8. [DOI: 10.1007/s10072-014-1681-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 02/11/2014] [Indexed: 11/27/2022]
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Bragatti JA, Torres CM, Cherubini PA, Leistner-Segal S, Bianchin MM. Is interictal EEG activity a biomarker for mood disorders in temporal lobe epilepsy? Clin Neurophysiol 2014; 125:1952-8. [PMID: 24631009 DOI: 10.1016/j.clinph.2014.02.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Revised: 01/20/2014] [Accepted: 02/15/2014] [Indexed: 11/18/2022]
Abstract
OBJECTIVE Psychiatric comorbidities are frequent in temporal lobe epilepsy (TLE), and symptoms of these comorbidities may be related to epilepsy activity. Here we evaluated interictal EEG activity in TLE patients with or without psychiatric comorbidities. METHODS A cohort study of 78 patients with TLE, with evaluation of wake/sleep interictal scalp EEG. All subjects were submitted to a psychiatric structured clinical interview (SCID) for the diagnosis of lifetime psychiatric comorbidities. Three major diagnostic categories were studied: mood disorders, anxiety disorders, and psychosis. We then evaluated differences in interictal EEG activity between patients with and without these psychiatric comorbidities. RESULTS Infrequent EEG interictal spikes, defined as less than one event per minute, were significantly associated with mood disorders in TLE (p=0.02). CONCLUSIONS Low intensity seizure disorder has been associated with a decrease in interictal EEG discharges and with an increase in psychiatric symptoms in TLE, a phenomenon known as forced normalization. In our study, we observed a low interictal spike frequency on EEG in TLE patients with mood disorders. SIGNIFICANCE A low spike index might be a neurophysiological marker for depression in temporal lobe epilepsy.
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Affiliation(s)
- José Augusto Bragatti
- Post-Graduation Course in Medicine, Medical Sciences, Universidade Federal do Rio Grande do Sul, Brazil; Basic Research and Advanced Investigations in Neurology, Experimental Research Centre, Hospital de Clínicas de Porto Alegre, Brazil; Division of Neurology, Hospital de Clínicas de Porto Alegre, Brazil.
| | - Carolina Machado Torres
- Post-Graduation Course in Medicine, Medical Sciences, Universidade Federal do Rio Grande do Sul, Brazil; Basic Research and Advanced Investigations in Neurology, Experimental Research Centre, Hospital de Clínicas de Porto Alegre, Brazil; Division of Neurology, Hospital de Clínicas de Porto Alegre, Brazil
| | - Pedro Abrahim Cherubini
- Basic Research and Advanced Investigations in Neurology, Experimental Research Centre, Hospital de Clínicas de Porto Alegre, Brazil
| | - Sandra Leistner-Segal
- Basic Research and Advanced Investigations in Neurology, Experimental Research Centre, Hospital de Clínicas de Porto Alegre, Brazil; Medical Genetics Service, Hospital de Clinicas de Porto Alegre, Brazil
| | - Marino Muxfeldt Bianchin
- Post-Graduation Course in Medicine, Medical Sciences, Universidade Federal do Rio Grande do Sul, Brazil; Basic Research and Advanced Investigations in Neurology, Experimental Research Centre, Hospital de Clínicas de Porto Alegre, Brazil; Division of Neurology, Hospital de Clínicas de Porto Alegre, Brazil
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Harward SC, McNamara JO. Aligning animal models with clinical epilepsy: where to begin? ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 813:243-51. [PMID: 25012381 DOI: 10.1007/978-94-017-8914-1_19] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Treatment of the epilepsies have benefitted immensely from study of animal models, most notably in the development of diverse anti-seizure medications in current clinical use. However, available drugs provide only symptomatic relief from seizures and are often ineffective. As a result, a critical need remains for developing improved symptomatic or disease-modifying therapies - or ideally, preventive therapies. Animal models will undoubtedly play a central role in such efforts. To ensure success moving forward, a critical question arises, namely "How does one make laboratory models relevant to our clinical understanding and treatment?" Our answer to this question: It all begins with a detailed understanding of the clinical phenotype one seeks to model. To make our case, we point to two examples - Fragile X syndrome and status epilepticus-induced mesial temporal lobe epilepsy - and examine how development of animal models for these distinct syndromes is based upon observations by astute clinicians and systematic study of the disorder. We conclude that the continuous and effective interaction of skilled clinicians and bench scientists is critical to the optimal design and study of animal models to facilitate insight into the nature of human disorders and enhance likelihood of improved therapies.
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Affiliation(s)
- Stephen C Harward
- Department of Neurobiology, Duke University Medical Center, Durham, NC, 27710, USA,
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Lee YJ, Lee JS. Temporal lobe epilepsy surgery in children versus adults: from etiologies to outcomes. KOREAN JOURNAL OF PEDIATRICS 2013; 56:275-81. [PMID: 23908666 PMCID: PMC3728445 DOI: 10.3345/kjp.2013.56.7.275] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Accepted: 02/01/2013] [Indexed: 11/27/2022]
Abstract
Temporal lobe epilepsy (TLE) is the most common type of medically intractable epilepsy in adults and children, and mesial temporal sclerosis is the most common underlying cause of TLE. Unlike in the case of adults, TLE in infants and young children often has etiologies other than mesial temporal sclerosis, such as tumors, cortical dysplasia, trauma, and vascular malformations. Differences in seizure semiology have also been reported. Motor manifestations are prominent in infants and young children, but they become less obvious with increasing age. Further, automatisms tend to become increasingly complex with age. However, in childhood and especially in adolescence, the clinical manifestations are similar to those of the adult population. Selective amygdalohippocampectomy can lead to excellent postoperative seizure outcome in adults, but favorable results have been seen in children as well. Anterior temporal lobectomy may prove to be a more successful surgery than amygdalohippocampectomy in children with intractable TLE. The presence of a focal brain lesion on magnetic resonance imaging is one of the most reliable independent predictors of a good postoperative seizure outcome. Seizure-free status is the most important predictor of improved psychosocial outcome with advanced quality of life and a lower proportion of disability among adults and children. Since the brain is more plastic during infancy and early childhood, recovery is promoted. In contrast, long epilepsy duration is an important risk factor for surgically refractory seizures. Therefore, patients with medically intractable TLE should undergo surgery as early as possible.
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Affiliation(s)
- Yun-Jin Lee
- Department of Pediatrics, Pusan National University Children's Hospital, Pusan National University School of Medicine, Yangsan, Korea
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Joshi S, Rajasekaran K, Kapur J. GABAergic transmission in temporal lobe epilepsy: the role of neurosteroids. Exp Neurol 2013; 244:36-42. [PMID: 22101060 PMCID: PMC3319002 DOI: 10.1016/j.expneurol.2011.10.028] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 10/21/2011] [Accepted: 10/28/2011] [Indexed: 01/21/2023]
Abstract
Modification of GABAergic inhibition is an intensely investigated hypothesis guiding research into mechanisms underlying temporal lobe epilepsy (TLE). Seizures can be initiated by blocking γ amino butyric acid type A (GABAA receptors, GABARs), which mediate fast synaptic inhibition in the brain, and controlled by drugs that enhance their function. Derivatives of steroid hormones called neurosteroids are natural substances that physiologically enhance GABAR function and suppress seizures. GABAR structure, function, expression, assembly, and pharmacological properties are changed in the hippocampus of epileptic animals. These alterations render GABARs less sensitive to neurosteroid modulation, which may contribute to seizure susceptibility. Plasticity of GABARs could play a role in periodic exacerbation of seizures experienced by women with epilepsy, commonly referred to as catamenial epilepsy.
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Affiliation(s)
- Suchitra Joshi
- Department of Neurology, University of Virginia Health Sciences Center, Box 800394, Charlottesville, VA 22908-0394, USA
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Pseudotemporal Ictal Patterns Compared With Mesial and Neocortical Temporal Ictal Patterns. J Clin Neurophysiol 2013; 30:238-46. [DOI: 10.1097/wnp.0b013e3182872f70] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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83
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Abstract
Temporal lobe epilepsy (TLE) is the most common form of adult localization-related epilepsy. Hippocampal onset accounts for at least 80% of all temporal lobe seizures. The electroencephalogram (EEG) of mesial TLE contains interictal features often associated with anterior temporal epileptiform discharges with a maximal voltage over the basal temporal electrodes. Localized ictal patterns on scalp EEGs characteristically reveal unilateral 5- to 9-Hz rhythmic ictal theta or alpha epileptiform activity maximal in the anterior temporal scalp electrodes. Invasive-scalp EEG comparisons have yielded direct information about mesial temporal sources and their corresponding electrical fields. Refinement of macroscopic spatial and the temporal resolution suggest that a more precise seizure localization may exist beyond 1- to 35-Hz frequencies observed in routine scalp recording. Defining the focal areas of ictogenesis within the medial temporal lobe demonstrates a rich connection to a broad network that goes beyond the medial structures and even the temporal lobe itself. Advanced electrophysiologic application in TLE may further our understanding of ictogenesis to perfect surgical treatment and to elucidate the neurophysiologic corollaries of epileptogensis itself.
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85
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Hamad APA, Carrete H, Bianchin MM, Ferrari-Marinho T, Lin K, Yacubian EMT, Vilanova LCP, Garzon E, Caboclo LO, Sakamoto AC. Morphological variations of hippocampal formation in epilepsy: image, clinical and electrophysiological data. Epilepsy Behav 2013; 26:67-70. [PMID: 23220462 DOI: 10.1016/j.yebeh.2012.10.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Revised: 10/12/2012] [Accepted: 10/15/2012] [Indexed: 11/15/2022]
Abstract
Morphological variations of hippocampal formation (MVHF) are observed in patients with epilepsy but also in asymptomatic individuals. The precise role of these findings in epilepsy is not yet fully understood. This study analyzes the hippocampal formation (HF) morphology of asymptomatic individuals (n = 30) and of patients with mesial temporal lobe epilepsy associated with hippocampal sclerosis (MTLE-HS) (n = 68), patients with malformations of cortical development (MCD) (n = 34), or patients with pure morphological variations of hippocampal formation (pure MVHF) (n = 12). Main clinical and electrophysiological data of patients with MVHF were also analyzed. Morphological variations of hippocampal formation are more frequently observed in patients with MCD than in patients with MTLE-HS or in asymptomatic individuals. Patients with pure morphological variations of hippocampal formation showed higher incidence of extratemporal seizure onset. Refractoriness seems to be more associated with other abnormalities, like HS or MCD, than with the HF variation itself. Thus, although morphological HF abnormalities might play a role in epileptogenicity, they seem to contribute less to refractoriness.
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Affiliation(s)
- Ana Paula Andrade Hamad
- Departamento de Neurologia e Neurocirurgia, Hospital São Paulo, Universidade Federal de São Paulo, Rua Napoleão de Barros, 865, Vila Clementino, São Paulo/SP, Brazil.
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86
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Abstract
The current study aimed to investigate the electroclinical differences between mesial temporal lobe epilepsy (MTLE) and posterior lateral temporal lobe epilepsy (PLTLE). All patients had Engel class I outcomes after surgery for at least one year. In MTLE patients, the epileptogenic zone was inside the boundary of a standard temporal lobectomy, whereas in PLTLE, the epileptogenic zone was behind the boundary of a standard temporal lobectomy. Febrile convulsion, history of psychic aura, oroalimentary automatism, and diffuse interictal epileptiform discharges were more frequent in MTLE. Theta wave and increasing heart rate were more evident at the seizure onset in MTLE, whereas an ictal onset fast rhythm was more evident in PLTLE. Tonic head turning was more frequent in PLTLE. Distinguishing between MTLE and PLTLE was easier than distinguishing MTLE from lateral TLE (LTLE), which may be helpful in planning epilepsy surgery. Combinations of these manifestations and signs can provide vital clues to distinguish between MTLE and PLTLE.
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Affiliation(s)
- Fang Wang
- Department of Neurology, Fu Xing Hospital, Capital Medical University, Beijing, PR China
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87
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Kuan YC, Shih YH, Chen C, Yu HY, Yiu CH, Lin YY, Kwan SY, Yen DJ. Abdominal auras in patients with mesial temporal sclerosis. Epilepsy Behav 2012; 25:386-90. [PMID: 23103315 DOI: 10.1016/j.yebeh.2012.07.034] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 07/26/2012] [Accepted: 07/28/2012] [Indexed: 10/27/2022]
Abstract
To better clarify abdominal auras and their clinical correlates, we enrolled 331 temporal lobe epilepsy patients who received surgical treatment. Detailed descriptions of their auras were obtained before surgery and reconfirmed during postoperative outpatient follow-ups. Pathology revealed mesial temporal sclerosis (MTS) in 256 patients (77.3%) and 75 non-MTS. Of 214 MTS patients with auras, 78 (36.4%) reported abdominal auras (vs. 30.4% in non-MTS, p=0.439): 42 with left-sided seizure onset, and 36 with right-sided seizure onset. Moreover, 49 of the 78 MTS patients had abdominal auras accompanied by rising sensations (vs. 2 of 14 in non-MTS group, p=0.004). The "rising air" was initially described to locate to the epigastric (47.8%) or periumbilical area (45.7%) and mostly reached the chest (40.4%) or remained in the abdominal region (27.1%). An epigastric location of "rising air" favored a left-sided seizure onset, and non-epigastric areas favored right-sided seizure onset (p=0.018). Finally, we found that abdominal auras with or without rising sensations did not predict postoperative seizure outcomes.
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Affiliation(s)
- Yi-Chun Kuan
- Department of Neurology, The Neurological Institute, Taipei Veterans General Hospital and National Yang-Ming University, Taipei, Taiwan
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88
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Tracy JI, Osipowicz K, Spechler P, Sharan A, Skidmore C, Doucet G, Sperling MR. Functional connectivity evidence of cortico-cortico inhibition in temporal lobe epilepsy. Hum Brain Mapp 2012; 35:353-66. [PMID: 22987774 DOI: 10.1002/hbm.22181] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 07/03/2012] [Accepted: 07/22/2012] [Indexed: 11/11/2022] Open
Abstract
Epileptic seizures can initiate a neural circuit and lead to aberrant neural communication with brain areas outside the epileptogenic region. We focus on interictal activity in focal temporal lobe epilepsy and evaluate functional connectivity (FC) differences that emerge as function of bilateral versus strictly unilateral epileptiform activity. We assess the strength of FC at rest between the ictal and non-ictal temporal lobes, in addition to whole brain connectivity with the ictal temporal lobe. Results revealed strong connectivity between the temporal lobes for both patient groups, but this did not vary as a function of unilateral versus bilateral interictal status. Both the left and right unilateral temporal lobe groups showed significant anti-correlated activity in regions outside the epileptogenic temporal lobe, primarily involving the contralateral (non-ictal/non-pathologic) hemisphere, with precuneus involvement prominent. The bilateral groups did not show this contralateral anti-correlated activity. This anti-correlated connectivity may represent a form of protective and adaptive inhibition, helping to constrain epileptiform activity to the pathologic temporal lobe. The absence of this activity in the bilateral groups may be indicative of flawed inhibitory mechanisms, helping to explain their more widespread epileptiform activity. Our data suggest that the location and build up of epilepsy networks in the brain are not truly random, and are not limited to the formation of strictly epileptogenic networks. Functional networks may develop to take advantage of the regulatory function of structures such as the precuneus to instantiate an anti-correlated network, generating protective cortico-cortico inhibition for the purpose of limiting seizure spread or epileptogenesis.
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Affiliation(s)
- Joseph I Tracy
- Department of Neurology, Thomas Jefferson University, Philadelphia, Pennsylvania
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89
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90
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Blümcke I, Coras R, Miyata H, Ozkara C. Defining clinico-neuropathological subtypes of mesial temporal lobe epilepsy with hippocampal sclerosis. Brain Pathol 2012; 22:402-11. [PMID: 22497612 DOI: 10.1111/j.1750-3639.2012.00583.x] [Citation(s) in RCA: 129] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Hippocampal sclerosis (HS) is the most frequent cause of drug-resistant focal epilepsies (ie, mesial temporal lobe epilepsy with hippocampal sclerosis; mTLE-HS), and presents a broad spectrum of electroclinical, structural and molecular pathology patterns. Many patients become drug resistant during the course of the disease, and surgical treatment was proven helpful to achieve seizure control. Hence, up to 40% of patients suffer from early or late surgical failures. Different patterns of hippocampal cell loss, involvement of other mesial temporal structures, as well as temporal neocortex including focal cortical dysplasia, may contribute to the extent of the epileptogenic network and will be discussed. An international consensus is mandatory to clarify terminology use and to reliably distinguish mTLE-HS subtypes. High-resolution imaging with confirmed histopathologic diagnosis, as well as advanced neurophysiologic and molecular genetic measures, will be a powerful tool in the future to address these issues and help to predict each patient's probability to control their epilepsy in mTLE-HS conditions.
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Affiliation(s)
- Ingmar Blümcke
- Department of Neuropathology, University Hospital Erlangen, Erlangen, Germany.
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91
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Blenkinsop A, Valentin A, Richardson MP, Terry JR. The dynamic evolution of focal-onset epilepsies - combining theoretical and clinical observations. Eur J Neurosci 2012; 36:2188-200. [DOI: 10.1111/j.1460-9568.2012.08082.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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92
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Alarcón G, Muthinji P, Kissani N, Polkey CE, Valentín A. Value of scalp delayed rhythmic ictal transformation (DRIT) in presurgical assessment of temporal lobe epilepsy. Clin Neurophysiol 2012; 123:1269-74. [DOI: 10.1016/j.clinph.2011.10.047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Revised: 10/18/2011] [Accepted: 10/22/2011] [Indexed: 10/15/2022]
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93
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Javidan M. Electroencephalography in mesial temporal lobe epilepsy: a review. EPILEPSY RESEARCH AND TREATMENT 2012; 2012:637430. [PMID: 22957235 PMCID: PMC3420622 DOI: 10.1155/2012/637430] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Revised: 01/17/2012] [Accepted: 02/23/2012] [Indexed: 11/17/2022]
Abstract
Electroencephalography (EEG) has an important role in the diagnosis and classification of epilepsy. It can provide information for predicting the response to antiseizure drugs and to identify the surgically remediable epilepsies. In temporal lobe epilepsy (TLE) seizures could originate in the medial or lateral neocortical temporal region, and many of these patients are refractory to medical treatment. However, majority of patients have had excellent results after surgery and this often relies on the EEG and magnetic resonance imaging (MRI) data in presurgical evaluation. If the scalp EEG data is insufficient or discordant, invasive EEG recording with placement of intracranial electrodes could identify the seizure focus prior to surgery. This paper highlights the general information regarding the use of EEG in epilepsy, EEG patterns resembling epileptiform discharges, and the interictal, ictal and postictal findings in mesial temporal lobe epilepsy using scalp and intracranial recordings prior to surgery. The utility of the automated seizure detection and computerized mathematical models for increasing yield of non-invasive localization is discussed. This paper also describes the sensitivity, specificity, and predictive value of EEG for seizure recurrence after withdrawal of medications following seizure freedom with medical and surgical therapy.
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Affiliation(s)
- Manouchehr Javidan
- Division of Neurology, Department of Medicine, University of British Columbia, Vancouver, BC, Canada V5Z 1M9
- Neurophysiology Laboratory, Vancouver General Hospital, Vancouver, BC, Canada V5Z1M9
- Epilepsy Program, Vancouver General Hospital, Vancouver, BC, Canada V5Z 1M9
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94
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Blair RDG. Temporal lobe epilepsy semiology. EPILEPSY RESEARCH AND TREATMENT 2012; 2012:751510. [PMID: 22957241 PMCID: PMC3420439 DOI: 10.1155/2012/751510] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/22/2011] [Accepted: 12/26/2011] [Indexed: 11/17/2022]
Abstract
Epilepsy represents a multifaceted group of disorders divided into two broad categories, partial and generalized, based on the seizure onset zone. The identification of the neuroanatomic site of seizure onset depends on delineation of seizure semiology by a careful history together with video-EEG, and a variety of neuroimaging technologies such as MRI, fMRI, FDG-PET, MEG, or invasive intracranial EEG recording. Temporal lobe epilepsy (TLE) is the commonest form of focal epilepsy and represents almost 2/3 of cases of intractable epilepsy managed surgically. A history of febrile seizures (especially complex febrile seizures) is common in TLE and is frequently associated with mesial temporal sclerosis (the commonest form of TLE). Seizure auras occur in many TLE patients and often exhibit features that are relatively specific for TLE but few are of lateralizing value. Automatisms, however, often have lateralizing significance. Careful study of seizure semiology remains invaluable in addressing the search for the seizure onset zone.
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Affiliation(s)
- Robert D. G. Blair
- Division of Neurology, Department of Medicine, Credit Valley Hospital, University of Toronto, Mississauga, ON, Canada L5M 2N1
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95
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Hara K, Ohta K, Miyajima M, Hara M, Iino H, Matsuda A, Watanabe S, Matsushima E, Maehara T, Matsuura M. Mismatch negativity for speech sounds in temporal lobe epilepsy. Epilepsy Behav 2012; 23:335-41. [PMID: 22377331 DOI: 10.1016/j.yebeh.2012.01.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Revised: 01/15/2012] [Accepted: 01/17/2012] [Indexed: 11/18/2022]
Abstract
The mismatch negativity (MMN) is an electrophysiological trace of change detection, measured by electroencephalography (EEG), and is a reliable marker for pre-attentive auditory sensory memory. We used a phonetic oddball paradigm in patients with temporal lobe epilepsy (TLE) to elicit the MMN response at fronto-central sites and the mismatch positivity (MMP) response at mastoid sites. The MMN in 26 patients was compared with that of 26 age- and gender-matched healthy control participants. Electroencephalography responses were recorded during the presentation of speech sounds: the vowels 'a' and 'o' in alternation. Average waveforms were obtained for standard and deviant trials. We found that the MMP response at bilateral mastoid sites was reduced, whereas the MMN response at fronto-central sites did not change significantly. These results support the view that the MMN is generated by separable sources in the frontal and temporal lobes and that these sources are differentially affected by TLE.
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Affiliation(s)
- Keiko Hara
- Department of Life Sciences and Biofunctional Informatics, Graduate School of Health Care Sciences, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan.
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96
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97
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Affiliation(s)
- Ciğdem Ozkara
- Department of Neurology, Cerrahpasa Medical Faculty, Istanbul University, Istanbul, Turkey.
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98
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Epilepsy. Neurology 2012. [DOI: 10.1007/978-0-387-88555-1_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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99
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Venugopal AK, Sameer Kumar GS, Mahadevan A, Selvan LDN, Marimuthu A, Dikshit JB, Tata P, Ramachandra Y, Chaerkady R, Sinha S, Chandramouli B, Arivazhagan A, Satishchandra P, Shankar S, Pandey A. Transcriptomic Profiling of Medial Temporal Lobe Epilepsy. ACTA ACUST UNITED AC 2012; 5. [PMID: 23483634 DOI: 10.4172/jpb.1000210] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Epilepsy is one of the most prevalent neurological disorders affecting ~1% of the population. Medial temporal lobe epilepsy (MTLE) is the most frequent type of epilepsy observed in adults who do not respond to pharmacological treatment. The reason for intractability in these patients has not been systematically studied. Further, no markers are available that can predict the subset of patients who will not respond to pharmacotherapy. To identify potential biomarkers of epileptogenicity, we compared the mRNA profiles of surgically resected tissue from seizure zones with non-seizure zones from cases of intractable MTLE. We identified 413 genes that exhibited ≥2-fold change that were statistically significant across these two groups. Several of these differentially expressed genes have not been previously described in the context of MTLE including claudin 11 (CLDN11) and bone morphogenetic protein receptor, type IB (BMPR1B). In addition, we found significant downregulation of a subset of gamma-aminobutyric acid (GABA) associated genes. We also identified molecules such as BACH2 and ADAMTS15, which are already known to be associated with epilepsy. We validated one upregulated molecule, serine/threonine kinase 31 (STK31) and one downregulated molecule, SMARCA4, by immunohistochemical labeling of tissue sections. These molecules need to be further confirmed in large-scale studies to determine their potential use as diagnostic as well as prognostic markers in intractable MTLE.
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Affiliation(s)
- Abhilash K Venugopal
- Institute of Bioinformatics, International Technology Park, Bangalore, India ; Department of Biotechnology, Kuvempu University, Shimoga, India ; McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA ; Departments of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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100
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Smith AP, Sani S, Kanner AM, Stoub T, Morrin M, Palac S, Bergen DC, Balabonov A, Smith M, Whisler WW, Byrne RW. Medically intractable temporal lobe epilepsy in patients with normal MRI: Surgical outcome in twenty-one consecutive patients. Seizure 2011; 20:475-9. [DOI: 10.1016/j.seizure.2011.02.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 12/29/2010] [Accepted: 02/25/2011] [Indexed: 10/18/2022] Open
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