THE RELATION BETWEEN CLINICAL, EPILEPTIFORM DISCHARGES, AND NEUROMETABOLIC DYSFUNCTION IN TEMPORAL LOBE EPILEPSY

Temporal lobe epilepsy (TLE) is one of the most common types of focal epilepsy, characterized by recurrent spontaneous seizures originating in the temporal lobe(s), with mesial TLE (mTLE) as the worst form of TLE, often associated with hippocampal sclerosis. Abnormal epileptiform discharges are the result, among others, of altered cell-to-cell communication in both chemical and electrical transmissions. Current knowledge about the neurobiology of TLE in human patients emerges from pathological studies of biopsy specimens isolated from the epileptogenic zone or, in a few more recent investigations, from living subjects using positron emission tomography (PET). To overcome limitations related to the use of human tissue, animal models are of great help as they allow the selection of homogeneous samples still presenting a more various scenario of the epileptic syndrome, the presence of a comparable control group, and the availability of a greater amount of tissue for in vitro/ex vivo investigations. This review provides an overview of the structural and functional alterations of synaptic connections in the brain of TLE/mTLE patients and animal models.

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Magnetoencephalography to confirm epileptiform discharges mimicking small sharp spikes in temporal lobe epilepsy

Clinical Neurophysiology ◽

10.1016/j.clinph.2021.03.049 ◽

2021 ◽

Author(s):

Dai Agari ◽

Kazutaka Jin ◽

Yosuke Kakisaka ◽

Akitake Kanno ◽

Makoto Ishida ◽

...

Keyword(s):

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Epileptiform Discharges

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Ictal scalp EEG in temporal lobe epilepsy with unitemporal versus bitemporal interictal epileptiform discharges

Neurology ◽

10.1212/wnl.45.5.889 ◽

1995 ◽

Vol 45 (5) ◽

pp. 889-896 ◽

Cited By ~ 102

Author(s):

B. J. Steinhoff ◽

N. K. So ◽

S. Lim ◽

H. O. Luders

Keyword(s):

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Scalp Eeg ◽

Epileptiform Discharges ◽

Interictal Epileptiform Discharges

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Electroencephalographic Features of Temporal Lobe Epilepsy

Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques ◽

10.1017/s0317167100010441 ◽

2010 ◽

Vol 37 (4) ◽

pp. 439-448 ◽

Cited By ~ 19

Author(s):

Mohammed M. Jan ◽

Mark Sadler ◽

Susan R. Rahey

Keyword(s):

Temporal Lobe Epilepsy ◽

Surgical Management ◽

Temporal Lobe ◽

Seizure Onset ◽

Resective Surgery ◽

Accurate Localization ◽

Epileptiform Discharges ◽

Ictal Eeg ◽

Temporal Lobe Seizures ◽

Eeg Recordings

Electroencephalography (EEG) is an important tool for diagnosing, lateralizing and localizing temporal lobe seizures. In this paper, we review the EEG characteristics of temporal lobe epilepsy (TLE). Several “non-standard” electrodes may be needed to further evaluate the EEG localization, Ictal EEG recording is a major component of preoperative protocols for surgical consideration. Various ictal rhythms have been described including background attenuation, start-stop-start phenomenon, irregular 2-5 Hz lateralized activity, and 5-10 Hz sinusoidal waves or repetitive epileptiform discharges. The postictal EEG can also provide valuable lateralizing information. Postictal delta can be lateralized in 60% of patients with TLE and is concordant with the side of seizure onset in most patients. When patients are being considered for resective surgery, invasive EEG recordings may be needed. Accurate localization of the seizure onset in these patients is required for successful surgical management.

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Reassessing the impact of intraoperative electrocorticography on postoperative outcome of patients undergoing standard temporal lobectomy for MRI-negative temporal lobe epilepsy

Journal of Neurosurgery ◽

10.3171/2018.11.jns182124 ◽

2020 ◽

Vol 132 (2) ◽

pp. 605-614 ◽

Cited By ~ 3

Author(s):

Sanjeet S. Grewal ◽

Mohammed Ali Alvi ◽

William J. Perkins ◽

Gregory D. Cascino ◽

Jeffrey W. Britton ◽

...

Keyword(s):

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Univariate Analysis ◽

Temporal Lobectomy ◽

Seizure Outcome ◽

Incomplete Resection ◽

Seizure Recurrence ◽

Cox Regression Analysis ◽

Epileptiform Discharges ◽

The Impact

OBJECTIVEAlmost 30% of the patients with suspected temporal lobe epilepsy (TLE) have normal results on MRI. Success rates for resection of MRI-negative TLE are less favorable, ranging from 36% to 76%. Herein the authors describe the impact of intraoperative electrocorticography (ECoG) augmented by opioid activation and its effect on postoperative seizure outcome.METHODSAdult and pediatric patients with medically resistant MRI-negative TLE who underwent standardized ECoG at the time of their elective anterior temporal lobectomy (ATL) with amygdalohippocampectomy between 1990 and 2016 were included in this study. Seizure recurrence comprised the primary outcome of interest and was assessed using Kaplan-Meier and multivariable Cox regression analysis plots based on distribution of interictal epileptiform discharges (IEDs) recorded on scalp electroencephalography, baseline and opioid-induced IEDs on ECoG, and extent of resection.RESULTSOf the 1144 ATLs performed at the authors’ institution between 1990 and 2016, 127 (11.1%) patients (81 females) with MRI-negative TLE were eligible for this study. Patients with complete resection of tissue generating IED recorded on intraoperative ECoG were less likely to have seizure recurrence compared to those with incomplete resection on univariate analysis (p < 0.05). No difference was found in seizure recurrence between patients with bilateral independent IEDs and unilateral IEDs (p = 0.15), presence or absence of opioid-induced epileptiform activation (p = 0.61), or completeness of resection of tissue with opioid-induced IEDs on intraoperative ECoG (p = 0.41).CONCLUSIONSThe authors found that incomplete resection of IED-generating tissue on intraoperative ECoG was associated with an increased chance of seizure recurrence. However, they found that induction of epileptiform activity with intraoperative opioid activation did not provide useful intraoperative data predictive of improving operative results for temporal lobectomy in MRI-negative epilepsy.

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