TEMPORAL GAP BETWEEN THE DIAGNOSIS OF DRUG RESISTANT TEMPORAL LOBE EPILEPSY ASSOCIATED WITH HIPPOCAMPAL SCLEROSIS AND INDICATION OF EPILEPSY SURGERY

Object Hippocampal sclerosis can be identified in most patients with mesial temporal lobe epilepsy (TLE). Surgical removal of the sclerotic hippocampus is widely performed to treat patients with drug-resistant mesial TLE. In general, both epilepsy-prone and epilepsy-resistant neurons are believed to be in the hippocampal formation. The hilar mossy cells of the hippocampal dentate gyrus are usually considered one of the most vulnerable types of neurons. The aim of this study was to clarify the fate of mossy cells in the hippocampus in epileptic humans. Methods Of the 19 patients included in this study, 15 underwent temporal lobe resection because of drug-resistant TLE. Four patients were used as controls because they harbored tumors that had not invaded the hippocampus and they had experienced no seizures. Histological evaluation of resected hippocampal tissues was performed using immunohistochemistry. Results Mossy cells were identified in the control as well as the epileptic hippocampi by using cocaine- and amphetamine-regulated transcript peptide immunohistochemistry. In most cases the number of mossy cells was reduced and thorny excrescences were smaller in the epileptic hippocampi than in controls; however, there was a significant loss of pyramidal cells and a partial loss of granule cells in the same epileptic hippocampi in which mossy cell loss was apparent. The loss of mossy cells could be correlated with the extent of hippocampal sclerosis, patient age at seizure onset, duration of epilepsy, and frequency of seizures. Conclusions In many cases large numbers of mossy cells were present in the hilus of the dentate gyrus when most pyramidal neurons of the CA1 and CA3 areas of the Ammon's horn were lost, suggesting that mossy cells may not be more vulnerable to epileptic seizures than the hippocampal pyramidal neurons.

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VISUAL FIELD DEFECTS IN SELECTIVE AMYGDALOHIPPOCAMPECTOMY FOR HIPPOCAMPAL SCLEROSIS

Neurosurgery ◽

10.1227/01.neu.0000324895.19708.68 ◽

2008 ◽

Vol 63 (3) ◽

pp. 507-515 ◽

Cited By ~ 30

Author(s):

S. Naz Yeni ◽

Necmettin Tanriover ◽

Özlem Uyanik ◽

Mustafa Onur Ulu ◽

Çiğdem Özkara ◽

...

Keyword(s):

Visual Field ◽

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Epilepsy Surgery ◽

Hippocampal Sclerosis ◽

Visual Field Defects ◽

Selective Amygdalohippocampectomy ◽

Temporal Horn ◽

Visual Field Deficits ◽

Meyer’S Loop

ABSTRACT OBJECTIVE Meyer's loop, the most vulnerable part of the optic radiations during approaches to the temporomedial region, extends to the tip of the temporal horn and is often encountered in epilepsy surgery. The risk of damaging Meyer's loop during transsylvian selective amygdalohippocampectomy peaks while accessing the temporal horn through its roof by opening the inferior limiting sulcus of the insula. In this prospective study, we sought to evaluate and identify the incidence of visual field deficits in a homogeneous group of patients who had temporal lobe epilepsy with hippocampal sclerosis and who underwent transsylvian selective amygdalohippocampectomy. METHODS We studied 30 patients who were referred for epilepsy surgery for intractable complex partial and/or secondary generalized seizures and evaluated according to a noninvasive protocol. All patients underwent selective amygdalohippocampectomy for temporal lobe epilepsy with hippocampal sclerosis using the standard transsylvian approach. Visual field deficits were examined preoperatively in 30 patients, by either a confrontation method (n = 18) or standard Goldmann perimetry (n = 12) and postoperatively in all patients using standard Humphrey digital perimetry. RESULTS Visual field examination was normal in all patients before surgery. Humphrey perimetric measurement revealed visual field deficits in 11 patients (36.6%) after surgery. CONCLUSION We have shown that there is a considerable risk of having visual field deficits after standard transsylvian selective amygdalohippocampectomy owing to the interruption of the anterior bundle of the optic radiation fibers, which most likely occurs while opening the temporal horn through the inferior limiting sulcus of the insula.

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Prevalence and Incidence of Drug-Resistant Temporal Lobe Epilepsy in Qatar

Journal of Central Nervous System Disease ◽

10.1177/1179573520935031 ◽

2020 ◽

Vol 12 ◽

pp. 117957352093503

Author(s):

Boulenouar Mesraoua ◽

Dirk Deleu ◽

Hassan J Al Hail ◽

Gayane Melikyan ◽

Musab Abdalhalim Ali ◽

...

Keyword(s):

Systematic Review ◽

Developing Countries ◽

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Hippocampal Sclerosis ◽

International Literature ◽

Drug Resistant ◽

Electronic Database ◽

Search Terms

Background: Information on the epidemiology of temporal lobe epilepsy associated with hippocampal sclerosis (TLE-HS) from Qatar and the developing countries is scarce. To acquire knowledge on the incidence and prevalence of drug-resistant TLE-HS in Qatar, we designed this analytical and extrapolative systematic review of the existing literature. Material and methods: We searched the electronic database PubMed from 1947 until April, 2018, using the following search terms in the title: “epilepsy” OR “temporal lobe” OR “hippocampal sclerosis” AND “epidemiology” OR “incidence” OR “prevalence.” Relevant original studies, reviews, and their references, were included. We extrapolated from the previous international literature to estimate the epidemiology of drug-resistant TLE-HS in Qatar. Results: The estimated Qatar incidence of epilepsy varies from 50 to 61 per 100 000 persons per year, and the estimated prevalence of epilepsy is 6.54 per 1000 population; the estimated incidence of TLE varies from 9.5 to 11.6 patients per 100 000 population per year and the estimated prevalence of TLE is 1.76 patients per 1000 people, with 4721 patients having TLE in Qatar. Finally, the reviewed studies also helped in making an estimate of the Qatar prevalence of drug-resistant TLE-HS to be between 0.3 and 0.6 cases per 1000 people (804-1609 current patients) and the Qatar incidence of drug-resistant TLE-HS (2.3-4.3 cases per 100 000 people, per year) with 62 to 116 new patients per year. Conclusion: Our study suggests that 804 to 1609 current patients (with 62-116 additional patients per year) in Qatar are suffering from drug-resistant TLE-HS; emphasis should be placed on the surgical aspect of the current Qatar Comprehensive Epilepsy Program.

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Temporal lobe epilepsy due to hippocampal sclerosis in pediatric candidates for epilepsy surgery

Neurology ◽

10.1212/wnl.56.12.1643 ◽

2001 ◽

Vol 56 (12) ◽

pp. 1643-1649 ◽

Cited By ~ 121

Author(s):

A. Mohamed ◽

E. Wyllie ◽

P. Ruggieri ◽

P. Kotagal ◽

T. Babb ◽

...

Keyword(s):

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Epilepsy Surgery ◽

Hippocampal Sclerosis

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Dentate gyrus expression of nestin-immunoreactivity in patients with drug-resistant temporal lobe epilepsy and hippocampal sclerosis

Seizure ◽

10.1016/j.seizure.2015.02.008 ◽

2015 ◽

Vol 27 ◽

pp. 75-79 ◽

Cited By ~ 6

Author(s):

L. D’Alessio ◽

H. Konopka ◽

E. Escobar ◽

A. Acuña ◽

S. Oddo ◽

...

Keyword(s):

Temporal Lobe Epilepsy ◽

Dentate Gyrus ◽

Temporal Lobe ◽

Hippocampal Sclerosis ◽

Drug Resistant

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Relation of Structural and Functional Changes in Auditory and Visual Pathways after Temporal Lobe Epilepsy Surgery

Behavioral Sciences ◽

10.3390/bs8100092 ◽

2018 ◽

Vol 8 (10) ◽

pp. 92

Author(s):

Margarita Báez-Martín ◽

Lilia Morales-Chacón ◽

Iván García-Maeso ◽

Bárbara Estupiñán-Díaz ◽

María García-Navarro ◽

...

Keyword(s):

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Epilepsy Surgery ◽

Visual Pathway ◽

Visual Pathways ◽

Temporal Lobectomy ◽

Epileptogenic Zone ◽

Drug Resistant ◽

Anatomical Connectivity ◽

Anatomical Connection

Auditory and visual pathways may be affected as a consequence of temporal lobe epilepsy surgery because of their anatomical relationships with this structure. The purpose of this paper is to correlate the results of the auditory and visual evoked responses with the parameters of tractography of the visual pathway, and with the state of connectivity between respective thalamic nuclei and primary cortices in both systems after the surgical resection of the epileptogenic zone in drug-resistant epileptic patients. Tractography of visual pathway and anatomical connectivity of auditory and visual thalamus-cortical radiations were evaluated in a sample of eight patients. In general, there was a positive relationship of middle latency response (MLR) latency and length of resection, while a negative correlation was found between MLR latency and the anatomical connection strength and anatomical connection probability of the auditory radiations. In the visual pathway, significant differences between sides were found with respect to the number and length of tracts, which was lower in the operated one. Anatomical connectivity variables and perimetry (visual field defect index) were particularly correlated with the latency of P100 wave which was obtained by quadrant stimulation. These results demonstrate an indirect functional modification of the auditory pathway and a direct traumatic lesion of the visual pathway after anterior temporal lobectomy in patients with drug resistant epilepsy.

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Temporal plus epilepsy is a major determinant of temporal lobe surgery failures

Brain ◽

10.1093/brain/awv372 ◽

2015 ◽

Vol 139 (2) ◽

pp. 444-451 ◽

Cited By ~ 86

Author(s):

Carmen Barba ◽

Sylvain Rheims ◽

Lorella Minotti ◽

Marc Guénot ◽

Dominique Hoffmann ◽

...

Keyword(s):

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Epilepsy Surgery ◽

Hippocampal Sclerosis ◽

Cox Proportional Hazards Model ◽

Temporal Lobectomy ◽

Seizure Freedom ◽

Epileptogenic Zone ◽

Anterior Temporal Lobectomy

Abstract See Engel (doi:10.1093/awv374) for a scientific commentary on this article. Reasons for failed temporal lobe epilepsy surgery remain unclear. Temporal plus epilepsy, characterized by a primary temporal lobe epileptogenic zone extending to neighboured regions, might account for a yet unknown proportion of these failures. In this study all patients from two epilepsy surgery programmes who fulfilled the following criteria were included: (i) operated from an anterior temporal lobectomy or disconnection between January 1990 and December 2001; (ii) magnetic resonance imaging normal or showing signs of hippocampal sclerosis; and (iii) postoperative follow-up ≥ 24 months for seizure-free patients. Patients were classified as suffering from unilateral temporal lobe epilepsy, bitemporal epilepsy or temporal plus epilepsy based on available presurgical data. Kaplan-Meier survival analysis was used to calculate the probability of seizure freedom over time. Predictors of seizure recurrence were investigated using Cox proportional hazards model. Of 168 patients included, 108 (63.7%) underwent stereoelectroencephalography, 131 (78%) had hippocampal sclerosis, 149 suffered from unilateral temporal lobe epilepsy (88.7%), one from bitemporal epilepsy (0.6%) and 18 (10.7%) from temporal plus epilepsy. The probability of Engel class I outcome at 10 years of follow-up was 67.3% (95% CI: 63.4–71.2) for the entire cohort, 74.5% (95% CI: 70.6–78.4) for unilateral temporal lobe epilepsy, and 14.8% (95% CI: 5.9–23.7) for temporal plus epilepsy. Multivariate analyses demonstrated four predictors of seizure relapse: temporal plus epilepsy (P < 0.001), postoperative hippocampal remnant (P = 0.001), past history of traumatic or infectious brain insult (P = 0.022), and secondary generalized tonic-clonic seizures (P = 0.023). Risk of temporal lobe surgery failure was 5.06 (95% CI: 2.36–10.382) greater in patients with temporal plus epilepsy than in those with unilateral temporal lobe epilepsy. Temporal plus epilepsy represents a hitherto unrecognized prominent cause of temporal lobe surgery failures. In patients with temporal plus epilepsy, anterior temporal lobectomy appears very unlikely to control seizures and should not be advised. Whether larger resection of temporal plus epileptogenic zones offers greater chance of seizure freedom remains to be investigated.

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Determination of the Initial Abnormal Discharge Site in Temporal Lobe Epilepsy Through Combined EEG and Neuroimaging. What Is Next?

Frontiers in Neurology ◽

10.3389/fneur.2021.798228 ◽

2021 ◽

Vol 12 ◽

Author(s):

Ana A. Rentería-Palomo ◽

Jose L. Montes-Ochoa ◽

Adriana Martinez-Mayorga ◽

Jorge Guillermo Reyes-Vaca ◽

Ildefonso Rodríguez-Leyva

Keyword(s):

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Latin American ◽

Epilepsy Surgery ◽

Comprehensive Evaluation ◽

Hippocampal Sclerosis ◽

Hippocampal Atrophy ◽

Significant Difference ◽

The Relationship

Objective: The objective of this study was to determine the relationship between atrophy of the hippocampus and severity of epilepsy in patients with temporal lobe epilepsy (TLE) as the first step to evaluate the possibility of surgery for epilepsy and analyze why patients cannot undergo epilepsy surgery.Methods: Volumetric MRI of the hippocampus was performed in 51 consecutive patients (29 men; mean age 40) with TLE. TLE diagnosis, lateralization, and severity (mild, moderate, severe) of seizures were based on a comprehensive evaluation that included neurologic examination and EEG in all patients. Patients with evidence of a lesion other than hippocampal sclerosis were not included in the study. We assessed the relationship between hippocampal volumes and electrophysiological evidence of seizure severity.Results: According to the affected side based on the EEG, a statistically significant difference (p < 0.001) in volume and a positive correlation between epilepsy and hippocampal atrophy were found.Conclusion: Our results confirm that volume loss to the hippocampus in patients with TLE correlates with the severity of epilepsy based on the EEG. Therefore, surgical treatment is considered early when hippocampal atrophy is evident in patients with refractory TLE. However, in Latin American countries, it is a challenge to get a patient to undergo epilepsy surgery. Therefore, we try to analyze the sad situation in our hospital.

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