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Abstract
The relevance of secondary epileptogenesis for human epilepsy remains a controversial subject decades after it was first described in animal models. Whether or not a previously normal brain region can become independently epileptogenic through a kindling-like process has not, and cannot, be definitely proven in humans. Rather than reliance on direct experimental evidence, attempts to answering this question must depend on observational data. In this review, observations based largely upon contemporary surgical series will advance the case for secondary epileptogenesis in humans. As will be argued, hypothalamic hamartoma-related epilepsy provides the strongest case for this process; all the stages of secondary epileptogenesis can be observed. Hippocampal sclerosis (HS) is another pathology where the question of secondary epileptogenesis frequently arises, and observations from bitemporal and dual pathology series are explored. The verdict here is far more difficult to reach, in large part because of the scarcity of longitudinal cohorts; moreover, recent experimental data have challenged the claim that HS is acquired consequent to recurrent seizures. Synaptic plasticity more than seizure-induced neuronal injury is the likely mechanism of secondary epileptogenesis. Postoperative running-down phenomenon provides the best evidence that a kindling-like process occurs in some patients, evidenced by its reversal. Finally, a network perspective of secondary epileptogenesis is considered, as well as the possible role for subcortical surgical interventions.
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Affiliation(s)
- Stephen A Thompson
- Department of Medicine (Neurology), McMaster University, Hamilton, ON, Canada.
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Abdulrazeq HF, Kimata AR, Shao B, Svokos K, Ayub N, Nie D, Asaad WF. Laser amygdalohippocampotomy reduces contralateral hippocampal sub-clinical activity in bitemporal epilepsy: A case illustration of responsive neurostimulator ambulatory recordings. Epilepsy Behav Rep 2023; 25:100636. [PMID: 38162813 PMCID: PMC10755529 DOI: 10.1016/j.ebr.2023.100636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 11/29/2023] [Accepted: 11/30/2023] [Indexed: 01/03/2024] Open
Abstract
Responsive neurostimulation (RNS) is a valuable tool in the diagnosis and treatment of medication refractory epilepsy (MRE) and provides clinicians with better insights into patients' seizure patterns. In this case illustration, we present a patient with bilateral hippocampal RNS for presumed bilateral mesial temporal lobe epilepsy. The patient subsequently underwent a right sided LITT amygdalohippocampotomy based upon chronic RNS data revealing predominance of seizures from that side. Analyzing electrocorticography (ECOG) from the RNS system, we identified the frequency of high amplitude discharges recorded from the left hippocampal lead pre- and post- right LITT amygdalohippocampotomy. A reduction in contralateral interictal epileptiform activity was observed through RNS recordings over a two-year period, suggesting the potential dependency of the contralateral activity on the primary epileptogenic zone. These findings suggest that early targeted surgical resection or laser ablation by leveraging RNS data can potentially impede the progression of dependent epileptiform activity and may aid in preserving neurocognitive networks. RNS recordings are essential in shaping further management decisions for our patient with a presumed bitemporal epilepsy.
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Affiliation(s)
- Hael F. Abdulrazeq
- Department of Neurosurgery, Rhode Island Hospital, Providence, RI, United States
- The Warren Alpert Medical School of Brown University, Providence, RI, United States
| | - Anna R. Kimata
- Department of Neurosurgery, Rhode Island Hospital, Providence, RI, United States
- The Warren Alpert Medical School of Brown University, Providence, RI, United States
- Department of Neuroscience, Brown University, Providence, RI, United States
| | - Belinda Shao
- Department of Neurosurgery, Rhode Island Hospital, Providence, RI, United States
- The Warren Alpert Medical School of Brown University, Providence, RI, United States
| | - Konstantina Svokos
- Department of Neurosurgery, Rhode Island Hospital, Providence, RI, United States
- The Warren Alpert Medical School of Brown University, Providence, RI, United States
- Norman Prince Neurosciences Institute, Rhode Island Hospital & Hasbro Children’s Hospital, Providence, RI, United States
- Department of Neuroscience, Brown University, Providence, RI, United States
| | - Neishay Ayub
- The Warren Alpert Medical School of Brown University, Providence, RI, United States
- Norman Prince Neurosciences Institute, Rhode Island Hospital & Hasbro Children’s Hospital, Providence, RI, United States
- Department of Neurology, Rhode Island Hospital, Providence, RI, United States
| | - Duyu Nie
- The Warren Alpert Medical School of Brown University, Providence, RI, United States
- Norman Prince Neurosciences Institute, Rhode Island Hospital & Hasbro Children’s Hospital, Providence, RI, United States
- Department of Neurology, Rhode Island Hospital, Providence, RI, United States
| | - Wael F. Asaad
- Department of Neurosurgery, Rhode Island Hospital, Providence, RI, United States
- The Warren Alpert Medical School of Brown University, Providence, RI, United States
- Norman Prince Neurosciences Institute, Rhode Island Hospital & Hasbro Children’s Hospital, Providence, RI, United States
- Department of Neuroscience, Brown University, Providence, RI, United States
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Mascia A, Casciato S, De Risi M, Quarato PP, Morace R, D'Aniello A, Grammaldo LG, Pavone L, Picardi A, Esposito V, Di Gennaro G. Bilateral epileptogenesis in temporal lobe epilepsy due to unilateral hippocampal sclerosis: A case series. Clin Neurol Neurosurg 2021; 208:106868. [PMID: 34388593 DOI: 10.1016/j.clineuro.2021.106868] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 07/23/2021] [Accepted: 08/02/2021] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Bitemporal epilepsy (biTLE), a potential cause of failure in TLE surgery, is rarely associated with unilateral HS and could be suggested by not lateralizing ictal scalp EEG/interictal PET-FDG findings. We evaluated the proportion of biTLE in a population of drug-resistant TLE-HS subjects who underwent intracranial investigation for lateralizing purpose. METHODS We retrospectively included all consecutive refractory TLE-HS patients and not lateralizing ictal scalp EEG/interictal PET-FDG findings, investigated by intracranial bilateral longitudinal hippocampal electrodes. Demographic characteristics, electroclinical findings and seizure outcome were evaluated. RESULTS We identified 14 subjects (7 males; mean age 39.5 years; mean age at disease onset 14.4 years), 7 of them had biTLE diagnosed after intracranial investigations. In the remaining 7 with unilateral epileptogenesis (uniTLE) anterior temporal lobectomy was performed (6/7 were in Engel class I). Preoperative neuropsychological assessment differentiated biTLE from uniTLE, as it was normal in six uniTLE patients but only in one with biTLE (p < 0.05). CONCLUSIONS Not lateralizing ictal scalp EEG and functional imaging findings in TLEHS should alert about the possibility of a true biTLE also in presence of unilateral findings at MRI. Intracranial investigations with bilateral longitudinal hippocampal electrodes can localize the EZ with a good risk-benefit profile. Consistently with the warning on memory functions in TLE patients explored by using longitudinal hippocampal electrodes, further studies are needed to better define the optimal investigation strategy.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Angelo Picardi
- Centre of Behavioural Sciences and Mental Health, Italian National Institute of Health, Rome, Italy
| | - Vincenzo Esposito
- IRCCS NEUROMED, Pozzilli, Isernia, Italy; Department of Neurosurgery, "Sapienza" University, Rome, Italy
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Miró J, Ripollés P, Sierpowska J, Santurino M, Juncadella M, Falip M, Rodríguez-Fornells A. Autobiographical memory in epileptic patients after temporal lobe resection or bitemporal hippocampal sclerosis. Brain Imaging Behav 2021; 14:1074-1088. [PMID: 31102166 DOI: 10.1007/s11682-019-00113-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The human hippocampus is believed to be a crucial node in the neural network supporting autobiographical memory retrieval. Structural mesial temporal damage associated with temporal lobe epilepsy (TLE) provides an opportunity to systematically investigate and better understand the local and distal functional consequences of mesial temporal damage in the engagement of the autobiographical memory network. We examined 19 TLE patients (49.21 ± 11.55 years; 12 females) with unilateral mesial TLE (MTLE; 12 with anterior temporal lobe resection: 6 right MTLE, 6 left MTLE) or bilateral mesial TLE (7 BMTLE) and 18 matched healthy subjects. We used functional MRI (fMRI) with an adapted autobiographical memory paradigm and a specific neuropsychological test (Autobiographical Memory Interview, AMI). While engaged in the fMRI autobiographical memory paradigm, all groups activated a large fronto-temporo-parietal network. However, while this network was left lateralized for healthy participants and right MTLE patients, left MTLE and patients with BMTLE also showed strong activation in right temporal and frontal regions. Moreover, BMTLE and left MTLE patients also showed significant mild deficits in episodic autobiographical memory performance measured with the AMI test. The right temporal and extra-temporal fMRI activation, along with the impairment in autobiographical memory retrieval found in left MTLE and BMTLE patients suggest that alternate brain areas-other than the hippocampus-may also support this process, possibly due to neuroplastic effects.
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Affiliation(s)
- Júlia Miró
- Cognition and Brain Plasticity Group, Bellvitge Biomedical Research Institute-IDIBELL, Biomedical Campus Bellvitge, Feixa Llarga s/n, 08907 L'Hospitalet de Llobregat,, Barcelona, Spain.,Epilepsy Unit, Neurology Department, Universtiy Hospital of Bellvitge, 08907 L'fHospitalet de LLobregat,, Barcelona, Spain
| | - Pablo Ripollés
- Cognition and Brain Plasticity Group, Bellvitge Biomedical Research Institute-IDIBELL, Biomedical Campus Bellvitge, Feixa Llarga s/n, 08907 L'Hospitalet de Llobregat,, Barcelona, Spain.,Department of Psychology, New York University, New York, 10003, USA
| | - Joanna Sierpowska
- Cognition and Brain Plasticity Group, Bellvitge Biomedical Research Institute-IDIBELL, Biomedical Campus Bellvitge, Feixa Llarga s/n, 08907 L'Hospitalet de Llobregat,, Barcelona, Spain.,Department of Cognition, Development and Education Psychology, University of Barcelona, 08035, Barcelona, Spain
| | - Mila Santurino
- Epilepsy Unit, Neurology Department, Universtiy Hospital of Bellvitge, 08907 L'fHospitalet de LLobregat,, Barcelona, Spain
| | - Montserrat Juncadella
- Epilepsy Unit, Neurology Department, Universtiy Hospital of Bellvitge, 08907 L'fHospitalet de LLobregat,, Barcelona, Spain
| | - Mercè Falip
- Epilepsy Unit, Neurology Department, Universtiy Hospital of Bellvitge, 08907 L'fHospitalet de LLobregat,, Barcelona, Spain
| | - Antoni Rodríguez-Fornells
- Cognition and Brain Plasticity Group, Bellvitge Biomedical Research Institute-IDIBELL, Biomedical Campus Bellvitge, Feixa Llarga s/n, 08907 L'Hospitalet de Llobregat,, Barcelona, Spain. .,Department of Cognition, Development and Education Psychology, University of Barcelona, 08035, Barcelona, Spain. .,Catalan Institution for Research and Advanced Studies, ICREA, 08010 Barcelona, Spain.
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Řehulka P, Cimbálník J, Pail M, Chrastina J, Hermanová M, Brázdil M. Hippocampal high frequency oscillations in unilateral and bilateral mesial temporal lobe epilepsy. Clin Neurophysiol 2019; 130:1151-1159. [PMID: 31100580 DOI: 10.1016/j.clinph.2019.03.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 02/18/2019] [Accepted: 03/13/2019] [Indexed: 01/12/2023]
Abstract
OBJECTIVE The main aim of this study was to investigate the potential differences in terms of interictal high frequency oscillations (HFOs) between both hippocampi in unilateral (U-MTLE) and bilateral mesial temporal lobe epilepsy (B-MTLE). METHODS Sixteen patients with MTLE underwent bilateral hippocampal depth electrode implantation as part of epilepsy surgery evaluation. Interictal HFOs were detected automatically. The analyses entail comparisons of the rates and spatial distributions of ripples and fast ripples (FR) in hippocampi and amygdalae, with respect to the eventual finding of hippocampal sclerosis (HS). RESULTS In U-MTLE, higher ripple and FR rates were found in the hippocampi ipsilateral to the seizure onset than in the contralateral hippocampi. Non-epileptic hippocampi in U-MTLE were distinguished by significantly lower ripple rate than in the remaining analyzed hippocampi. There were not differences between the hippocampi in B-MTLE. In the hippocampi with proven HS, higher FR rates were observed in the ventral than in the dorsal parts. CONCLUSIONS Non-epileptic hippocampi in U-MTLE demonstrated significantly lower ripple rates than those epileptic in U-MTLE and B-MTLE. SIGNIFICANCE Low interictal HFO occurrence might be considered as a marker of the non-epileptic hippocampi in MTLE.
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Affiliation(s)
- Pavel Řehulka
- Brno Epilepsy Center, Department of Neurology, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic.
| | - Jan Cimbálník
- International Clinical Research Center, St. Anne's University Hospital, Brno, Czech Republic
| | - Martin Pail
- Brno Epilepsy Center, Department of Neurology, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Jan Chrastina
- Brno Epilepsy Center, Department of Neurosurgery, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Markéta Hermanová
- Brno Epilepsy Center, First Department of Pathology, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Milan Brázdil
- Brno Epilepsy Center, Department of Neurology, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic; Behavioral and Social Neuroscience Research Group, CEITEC - Central European Institute of Technology, Masaryk University, Brno, Czech Republic
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Zhou H, Ye X, Hong J, Liu Q, Ma J, Xu J. Multiphasic Side-Switching Seizures Are Easily Misdiagnosed as Unilateral Seizures During a Single EEG Monitoring Session: A Specific Subtype of Bitemporal Epilepsy. World Neurosurg 2019; 122:656-60. [PMID: 30481627 DOI: 10.1016/j.wneu.2018.11.138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 11/14/2018] [Accepted: 11/16/2018] [Indexed: 11/21/2022]
Abstract
BACKGROUND Bitemporal epilepsy (BTLE) is a specific anatomoelectroclinical phenotype in the spectrum of temporal lobe epilepsy. The diagnosis of BTLE and the evaluation of the degree of seizure lateralization in BTLE patients are greatly influenced by the duration of EEG recording and the number of recorded habitual seizures. CASE DESCRIPTION A 25-year-old woman had a 5-year history of seizures. Her habitual seizures were described as sudden behavioral arrest, staring, unresponsiveness, and oral automatisms, with auras of fear and palpitation. Intermittent scalp electroencephalography (EEG) and intracranial EEG monitoring over 3 years showed multiphasic side-switching seizures. The seizures were limited to 1 temporal lobe within 1 phase and switched sides between phases. Despite antiepileptic drugs and vagus nerve stimulation, her seizures remained uncontrolled. The patient finally underwent unilateral anteromedial temporal lobectomy, mainly based on >60% of seizures recorded originating from the left side. The patient has been seizure free for more than 1 year at last follow-up. CONCLUSIONS This patient presented 1 specific subtype of BTLE that is prone to be misdiagnosed as unilateral temporal lobe epilepsy if the patient is recorded for a relatively short term, e.g., over a common EEG monitoring duration of 1 to 2 weeks.
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