Hippocampal magnetic resonance imaging in focal onset seizure with impaired awareness—descriptive study from tertiary care centre in southern part of India

Abstract Background Temporal lobe epilepsy is the most common type of focal onset seizure. Focal onset seizure with impaired awareness, previously known as complex partial seizure (CPS), account for 18–40% of all seizure types. Hippocampal sclerosis (HS) is the most common cause of temporal lobe epilepsy, which produces focal onset seizure with impaired awareness. It may be detected in MRI visually, but bilateral abnormalities are better identified using volumetric analysis. We aimed to compare hippocampal volume in patients with focal onset seizure with impaired awareness visually and quantitatively. Methodology This cross-sectional study includes clinically diagnosed cases of 56 focal onset seizure with impaired awareness undergoing MRI at a tertiary teaching hospital in the southern part of India for a duration of 18 months from February 2018 to August 2019. Results Out of 53 patients studied using 1.5 T MRI brain with seizure protocols, hippocampal atrophy was identified visually in 13 (24.5%) on the right side, 9 (16.98%) on the left side, and in 6 (11.32%) bilaterally. However, with volumetry, hippocampal atrophy (not taking T2 signal change) was detected in 15 (28.30%) on the right side, 10 (18.86%) on the left side, and in 7 (13.20%) bilaterally. Hippocampal volumes between ipsilateral and contralateral seizure focus were found to have no significant difference (p-0.84). Conclusions Though visual analysis is efficient in the diagnosis of pathology, MR volumetry may be used as an expert eye in cases of subtle volume loss.

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Transsylvian hippocampal transection for mesial temporal lobe epilepsy: surgical indications, procedure, and postoperative seizure and memory outcomes

Journal of Neurosurgery ◽

10.3171/2013.6.jns13244 ◽

2013 ◽

Vol 119 (5) ◽

pp. 1098-1104 ◽

Cited By ~ 18

Author(s):

Takehiro Uda ◽

Michiharu Morino ◽

Hirotaka Ito ◽

Noriaki Minami ◽

Atsushi Hosono ◽

...

Keyword(s):

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Verbal Memory ◽

Memory Function ◽

Mesial Temporal Lobe Epilepsy ◽

Hippocampal Atrophy ◽

Delayed Recall ◽

Nonverbal Memory ◽

Mesial Temporal Lobe ◽

The Right

Object Amygdalohippocampectomy is a well-established, standard surgery for medically intractable mesial temporal lobe epilepsy (MTLE). However, in the case of MTLE without hippocampal atrophy or sclerosis, amygdalohippocampectomy is associated with decreased postoperative memory function. Hippocampal transection (HT) has been developed to overcome this problem. In HT the hippocampus is not removed; rather, the longitudinal hippocampal circuits of epileptic activities are disrupted by transection of the pyramidal layer of the hippocampus. The present study describes a less invasive modification of HT (transsylvian HT) and presents the seizure and memory outcomes for this procedure. Methods Thirty-seven patients with MTLE (18 men and 19 women; age range 9–63 years; 19 with surgery on the right side and 18 with surgery on the left side; seizure onset from 3 to 34 years) who were treated with transsylvian HT were retrospectively analyzed. All patients had left-side language dominance, and follow-up periods ranged from 12 to 94 months (median 49 months). Seizure outcomes were evaluated for all patients by using the Engel classification. Memory function was evaluated for 22 patients based on 3 indices (verbal memory, nonverbal memory, and delayed recall), with those scores obtained using the Wechsler Memory Scale–Revised. Patients underwent evaluation of the memory function before and after surgery (6 months–1 year). Results Engel Class I (completely seizure free) was achieved in 25 patients (67.6%). Class II and Class III designation was achieved in 10 (27%) and 2 patients (5.4%), respectively. There were differences in memory outcome between the sides of operation. On the right side, verbal memory significantly increased postoperatively (p = 0.003) but nonverbal memory and delayed recall showed no significant change after the operation (p = 0.718 and p = 0.210, respectively). On the left side, all 3 indices (verbal memory, nonverbal memory, and delayed recall) showed no significant change (p = 0.331, p = 0.458, and p = 0.366, respectively). Conclusions Favorable seizure outcome and preservation of verbal memory were achieved with transsylvian HT for the treatment of MTLE without hippocampal atrophy or sclerosis.

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MRI-negative Temporal Lobe Epilepsy: Is there a Role for PET?

Epilepsy Currents ◽

10.1111/j.1535-7511.2005.05308.x ◽

2005 ◽

Vol 5 (3) ◽

pp. 118-119 ◽

Cited By ~ 1

Author(s):

Theodore H. Schwartz

Keyword(s):

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Fdg Pet ◽

Visual Analysis ◽

Hippocampal Sclerosis ◽

Significant Difference ◽

Hippocampal Sparing ◽

Temporal Lobe Seizures ◽

Temporal Structures ◽

History Of

MRI-negative PET-positive Temporal Lobe Epilepsy: A Distinct Surgically Remediable Syndrome Carne RP, O'Brien TJ, Kilpatrick CJ, MacGregor LR, Hicks RJ, Murphy MA, Bowden SC, Kaye AH, Cook MJ Brain 2004;127:2276–2285 Most patients with nonlesional temporal lobe epilepsy (NLTLE) will have the findings of hippocampal sclerosis (HS) on a high-resolution MRI. However, a significant minority of patients with NLTLE and electroclinically well-lateralized temporal lobe seizures have no evidence of HS on MRI. Many of these patients have concordant hypometabolism on fluorodeoxyglucose-PET ([18F]FDG-PET). The pathophysiologic basis of this latter group remains uncertain. We aimed to determine whether NLTLE without HS on MRI represents a variant of or a different clinicopathologic syndrome from that of NLTLE with HS on MRI. The clinical, EEG, [18F]FDG-PET, histopathologic, and surgical outcomes of 30 consecutive NLTLE patients with well-lateralized EEG but without HS on MRI (HS–ve TLE) were compared with 30 consecutive age- and sex-matched NLTLE patients with well-lateralized EEG with HS on MRI (HS+ve TLE). Both the HS+ve TLE group and the HS–ve TLE patients had a high degree of [18F]FDG-PET concordant lateralization (26 of 30 HS–ve TLE vs. 27 of 27 HS+ve TLE). HS–ve TLE patients had more widespread hypometabolism on [18F]FDG-PET by blinded visual analysis [odds ratio (OR,+∞(2.51,–); P = 0.001]. The HS–ve TLE group less frequently had a history of febrile convulsions [OR,0.077 (0.002 to 0.512), P = 0.002], more commonly had a delta rhythm at ictal onset [OR,3.67 (0.97 to 20.47); P = 0.057], and less frequently had histopathologic evidence of HS [OR,0 (0 to 0.85); P = 0.031]. No significant difference in surgical outcome despite half of those without HS having a hippocampal-sparing procedure. Based on the findings outlined, HS–ve PET-positive TLE may be a surgically remediable syndrome distinct from HS+ve TLE, with a pathophysiologic basis that primarily involves lateral temporal neocortical rather than mesial temporal structures.

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Structural Abnormalities are Similar in Familial and Nonfamilial Mesial Temporal Lobe Epilepsy

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

10.1017/s0317167100003462 ◽

2004 ◽

Vol 31 (3) ◽

pp. 368-372 ◽

Cited By ~ 7

Author(s):

Fabio Thadeu Ferreira ◽

Eliane Kobayashi ◽

Iscia Lopes-Cendes ◽

Fernando Cendes

Keyword(s):

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Visual Analysis ◽

Mesial Temporal Lobe Epilepsy ◽

Control Group ◽

Hippocampal Atrophy ◽

Anterior Temporal Lobe ◽

Temporal Lobes ◽

Mesial Temporal Lobe ◽

Lobe Atrophy

Background/Objective:Diffuse temporal lobe abnormalities can be observed on MRI of patients with mesial temporal lobe epilepsy (MTLE). Our objective was to perform qualitative and quantitative analyses of temporal lobe structures in patients with familial MTLE (FMTLE) and nonfamilial MTLE.Methods:Two groups of patients were ascertained: 67 FMTLE patients (14 with refractory seizures) and 30 patients with nonfamilial refractory MTLE. We performed qualitative analyses of MRI (with multiplanar reconstruction) and volumes of hippocampi and anterior temporal lobes in all patients, and in a normal control group of 23 individuals. We used the Chi-square test and ANOVA for statistical analyses.Results:We identified anterior temporal lobe abnormalities by visual analysis in only 4% of FMTLE patients and atrophy of the anterior temporal lobe by volumetric analysis in 19%. In the group of nonfamilial MTLE patients we found anterior temporal lobe abnormalities by visual analysis in 17% of patients and anterior temporal lobe atrophy in 13%. Hippocampal atrophy was present in 90% of FMTLE and in 83% of nonfamilial MTLE. No signs of cortical dysplasia were observed.Conclusion:Anterior temporal lobe atrophy and other abnormalities outside the mesial portion of temporal lobes were infrequent in both familial and nonfamilial MTLE patients. Despite the genetic basis, hippocampal atrophy in FMTLE is not associated with other abnormalities outside the mesial temporal regions.

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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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Progressive contralateral hippocampal atrophy following Temporal Lobe Epilepsy Surgery (TLS)

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

10.1017/cjn.2015.130 ◽

2015 ◽

Vol 42 (S1) ◽

pp. S26-S27

Author(s):

CA Elliott ◽

C Yasuda ◽

L Concha ◽

M Liu ◽

M Wheatley ◽

...

Keyword(s):

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Time Course ◽

Hippocampal Volume ◽

Control Group ◽

Hippocampal Atrophy ◽

Subject Design ◽

Significant Difference ◽

Delayed Scan ◽

Over Time

Background: Temporal Lobe Epilepsy is associated with bilateral gray (GM) and white matter (WM) loss. After surgical treatment progressive bilateral temporal and extra-temporal WM change occur, however, less is known regarding post-operative GM change. We set out to measure contralateral hippocampal volume (CHV) following TLS. Methods: 1.5T-3D-1mm-isotropic-MPRAGE scans in 26 TLE patients and 3 controls in two groups: longitudinal (n=10)(imaged POD1,2,3,6,60,120 and >360d) and single post-operative scan (n=16). Manual volumetry protocols. Results: We find significant CHV atrophy at delayed scan relative to baseline (mean atrophy 26.8%). In the longitudinal group there is significant and progressive atrophy from baseline to POD4-8 (72.6+/-6.5%), POD60-360 (69.7+/-12.3%) and >360 (58.5+/-10.6%). No significant atrophy in either the control group HV or contralateral CV over time. No significant difference in mean HV at the most delayed exam for surgery type (p=0.13) or side (p=0.24). Conclusions: We find a statistically significant CHV atrophy following surgery which is progressive over time. Our longitudinal within-subject design describes the time course and extent more fully than previous work. Caudate analysis indicates that early CHV atrophy is not due to global atrophy following brain surgery but rather may be due to deafferentation and deefferentation. Finally, we find no significant difference in atrophy when analyzed by surgical approach or surgical side.

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Hippocampal atrophy and quantitative EEG markers in mild cognitive impairment in temporal lobe epilepsy versus extra-temporal lobe epilepsy

Neurological Sciences ◽

10.1007/s10072-021-05540-4 ◽

2021 ◽

Author(s):

Mohammed Elsherif ◽

Ahmed Esmael

Keyword(s):

Cognitive Impairment ◽

Mild Cognitive Impairment ◽

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Quantitative Eeg ◽

Hippocampal Atrophy

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Efficacy of hippocampal transection for left temporal lobe epilepsy without hippocampal atrophy

Epilepsy & Behavior ◽

10.1016/j.yebeh.2011.02.028 ◽

2011 ◽

Vol 21 (1) ◽

pp. 94-99 ◽

Cited By ~ 8

Author(s):

Shigeki Sunaga ◽

Michiharu Morino ◽

Taro Kusakabe ◽

Hidenori Sugano ◽

Hiroyuki Shimizu

Keyword(s):

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Hippocampal Atrophy ◽

Left Temporal Lobe

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Anterior temporal lobectomy versus selective amygdalohippocampectomy in patients with mesial temporal lobe epilepsy

Arquivos de Neuro-Psiquiatria ◽

10.1590/0004-282x20150188 ◽

2015 ◽

Vol 74 (1) ◽

pp. 35-43 ◽

Cited By ~ 12

Author(s):

Fábio A. Nascimento ◽

Luana Antunes Maranha Gatto ◽

Carlos Silvado ◽

Maria Joana Mäder-Joaquim ◽

Marlus Sidney Moro ◽

...

Keyword(s):

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Mesial Temporal Lobe Epilepsy ◽

Temporal Lobectomy ◽

Mesial Temporal Sclerosis ◽

Anterior Temporal Lobectomy ◽

Selective Amygdalohippocampectomy ◽

Significant Difference ◽

Mesial Temporal Lobe ◽

Neuropsychological Outcomes

ABSTRACT Objective To contribute our experience with surgical treatment of patients with mesial temporal lobe epilepsy (mTLE) undergoing anterior temporal lobectomy (ATL) or selective amygdalohippocampectomy (SelAH). Method This is a retrospective observational study. The sample included patients with medically refractory mTLE due to unilateral mesial temporal sclerosis who underwent either ATL or SelAH, at Hospital de Clinicas – UFPR, from 2005 to 2012. We report seizure outcomes, using Engel classification, cognitive outcomes, using measurements of verbal and visuospatial memories, as well as operative complications. Result Sixty-seven patients (33 ATL, 34 SelAH) were studied; median follow-up was 64 months. There was no statistically significant difference in seizure or neuropsychological outcomes, although verbal memory was more negatively affected in ATL operations on patients’ dominant hemispheres. Higher number of major complications was observed in the ATL group (p = 0.004). Conclusion Seizure and neuropsychological outcomes did not differ. ATL appeared to be associated with higher risk of complications.

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Intrinsic Thalamic Network in Temporal Lobe Epilepsy With Hippocampal Sclerosis According to Surgical Outcomes

Frontiers in Neurology ◽

10.3389/fneur.2021.721610 ◽

2021 ◽

Vol 12 ◽

Author(s):

Kyoo Ho Cho ◽

Ho-Joon Lee ◽

Kyoung Heo ◽

Sung Eun Kim ◽

Dong Ah Lee ◽

...

Keyword(s):

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Surgical Outcomes ◽

Hippocampal Sclerosis ◽

Three Dimensional ◽

Thalamic Nuclei ◽

Characteristic Path Length ◽

Ipsilateral Hemisphere ◽

Hippocampal Subfields ◽

Significant Difference

Background: The aim of this study was to identify the differences of intrinsic amygdala, hippocampal, or thalamic networks according to surgical outcomes in temporal lobe epilepsy (TLE) patients with hippocampal sclerosis (HS).Methods: We enrolled 69 pathologically confirmed TLE patients with HS. All patients had pre-operative three-dimensional T1-weighted MRI using a 3.0 T scanner. We obtained the structural volumes of the amygdala nuclei, hippocampal subfields, and thalamic nuclei. Then, we investigated the intrinsic networks based on volumes of these structures using structural covariance and graph theoretical analysis.Results: Of the 69 TLE patients with HS, 21 patients (42.1%) had poor surgical outcomes, whereas 40 patients (57.9%) had good surgical outcomes. The volumes in the amygdala nuclei, hippocampal subfields, and thalamic nuclei were not different according to surgical outcome. In addition, the intrinsic amygdala and hippocampal networks were not different between the patients with poor and good surgical outcomes. However, there was a significant difference in the intrinsic thalamic network in the ipsilateral hemisphere between them. The eccentricity and small-worldness index were significantly increased, whereas the characteristic path length was decreased in the patients with poor surgical outcomes compared to those with good surgical outcomes.Conclusion: We successfully demonstrated significant differences in the intrinsic thalamic network in the ipsilateral hemisphere between TLE patients with HS with poor and good surgical outcomes. This result suggests that the pre-operative intrinsic thalamic network can be related with surgical outcomes in TLE patients with HS.

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