The impact of epilepsy duration in a series of patients with mesial temporal lobe epilepsy due to unilateral hippocampal sclerosis

Duarte, Jeana Torres Corso; Jardim, Anaclara Prada; Comper, Sandra Mara; Marchi, Luciana Rodrigues De; Gaça, Larissa Botelho; Garcia, Maria Teresa Fernandes Castilho; Sandim, Gabriel Barbosa; Assunção-Leme, Idaiane Batista de; Carrete, Henrique; Centeno, Ricardo Silva; Lancellotti, Carmen Lúcia Penteado; Jackowski, Andrea Parolin; Cavalheiro, Ésper A.; Guaranha, Mirian Salvadori Bittar; Yacubian, Elza Márcia Targas

doi:10.1016/j.eplepsyres.2018.08.009

Cited by 15 publications

(16 citation statements)

References 28 publications

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“…We did not analyze amygdala volumes in this study. We found a lower pre-resection IQ was associated with a lower total volume of the resected hippocampus, which was expected as both worsen with longer duration of epilepsy (22).…”

Section: Discussionsupporting

confidence: 54%

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Are HFOs in the Intra-operative ECoG Related to Hippocampal Sclerosis, Volume and IQ?

et al. 2021

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Temporal lobe epilepsy (TLE) is the most common form of refractory focal epilepsy and is often associated with hippocampal sclerosis (HS) and cognitive disturbances. Over the last decade, high frequency oscillations (HFOs) in the intraoperative electrocorticography (ioECoG) have been proposed to be biomarkers for the delineation of epileptic tissue but hippocampal ripples have also been associated with memory consolidation. Healthy hippocampi can show prolonged ripple activity in stereo- EEG. We aimed to identify how the HFO rates [ripples (80–250 Hz, fast ripples (250–500 Hz); prolonged ripples (80–250 Hz, 200–500 ms)] in the pre-resection ioECoG over subtemporal area (hippocampus) and lateral temporal neocortex relate to presence of hippocampal sclerosis, the hippocampal volume quantified on MRI and the severity of cognitive impairment in TLE patients. Volumetric measurement of hippocampal subregions was performed in 47 patients with TLE, who underwent ioECoG. Ripples, prolonged ripples, and fast ripples were visually marked and rates of HFOs were calculated. The intellectual quotient (IQ) before resection was determined. There was a trend toward higher rates of ripples and fast ripples in subtemporal electrodes vs. the lateral neocortex (ripples: 2.1 vs. 1.3/min; fast ripples: 0.9 vs. 0.2/min). Patients with HS showed higher rates of subtemporal fast ripples than other patients (Z = −2.51, p = 0.012). Prolonged ripples were only found in the lateral temporal neocortex. The normalized ratio (smallest/largest) of hippocampal volume was correlated to pre-resection IQ (r = 0.45, p = 0.015). There was no correlation between HFO rates and hippocampal volumes or HFO rates and IQ. To conclude, intra-operative fast ripples were a marker for HS, but ripples and fast ripples were not linearly correlated with either the amount of hippocampal atrophy, nor for pre-surgical IQ.

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Section: Discussionsupporting

confidence: 54%

“…We know that HFOs are related to the seizure frequency at that time point (28). Seizure frequency is not necessarily related to the amount of atrophy at that time point, but mainly to the duration of epilepsy (22). We do not have information about current seizure frequency of this cohort but this could explain our findings.…”

Section: Discussionmentioning

confidence: 72%

Are HFOs in the Intra-operative ECoG Related to Hippocampal Sclerosis, Volume and IQ?

et al. 2021

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“…Prior work has suggested that disease duration in MRI-positive mTLE patients can cause progressive hippocampal atrophy ( 3 , 12 , 26 ). In studies that included pathology, hippocampal neuronal cell loss was found to underlie the diminished volumes ( 27 , 28 ). Similarly in our study, disease duration was found to have a statistically significant positive relationship with hippocampal asymmetry within the unilateral mTLE cohort.…”

Section: Discussionmentioning

confidence: 99%

Detection of Hippocampal Subfield Asymmetry at 7T With Automated Segmentation in Epilepsy Patients With Normal Clinical Strength MRIs

et al. 2021

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While the etiology of hippocampal sclerosis (HS) in epilepsy patients remains unknown, distinct phenotypes of hippocampal subfield atrophy have been associated with different clinical presentations and surgical outcomes. The advent of novel techniques including ultra-high field 7T magnetic resonance imaging (MRI) and automated subfield volumetry have further enabled detection of hippocampal pathology in patients with epilepsy, however, studies combining both 7T MRI and automated segmentation in epilepsy patients with normal-appearing clinical MRI are limited. In this study, we present a novel application of the automated segmentation of hippocampal subfields (ASHS) software to determine subfield volumes of the CA1, CA2/3, CA4/DG, and the subiculum using ultra high-field 7T MRI scans, including T1-weighted MP2RAGE and T2-TSE sequences, in 27 patients with either mesial temporal lobe epilepsy (mTLE) or neocortical epilepsy (NE) compared to age and gender matched healthy controls. We found that 7T improved visualization of structural abnormalities not otherwise seen on clinical strength MRIs in patients with unilateral mTLE. Additionally, our automated segmentation algorithm was able to detect structural differences in volume and asymmetry across hippocampal subfields in unilateral mTLE patients compared to controls. Specifically, amongst unilateral mTLE patients with longer disease durations, volume loss was observed in the ipsilateral CA1 and CA2/3 subfields and contralateral CA1. There were no differences in subfield volumes in patients with NE compared to controls. We report the first application of 7T with automated segmentation to characterize the relationship between disease duration burden and asymmetry across specific hippocampal subfields in this population. Disease duration was found to have a statistically significant positive relationship with subfield asymmetry within the unilateral mTLE cohort. These findings highlight the ability of 7T MRI and automated segmentation to provide novel qualitative and quantitative information in epilepsy patients who are otherwise MRI-negative at clinical field strengths.

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“…Mesial temporal lobe epilepsy (Schoene-Bake et al, 2014;Kim et al, 2015;Sone et al, 2016;Donos et al, 2018;Duarte et al, 2018;Kreilkamp et al, 2018;Long et al, 2018;Peixoto-Santos et al, 2018;Costa et al, 2019;Lee et al, 2019) Subfields as ROI for fiber tracking (Rutland et al, 2018)…”

Section: Epilepsymentioning

confidence: 99%

FreeSurfer based segmentation of hippocampal subfields: a review of methods and applications, with a novel quality control procedure for ENIGMA studies and other collaborative efforts

Sämann¹,

Iglesias²,

Gutman³

et al. 2020

Preprint

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Structural hippocampal abnormalities are common in many neurological and psychiatric disorders, and even variation within the normal range is related to cognitive performance and other complex phenotypes such as stress sensitivity. Hippocampal subregions are increasingly studied, as automated algorithms have become available for mapping and volume quantification. In the context of the ENIGMA Consortium, several Disease Working Groups are using the FreeSurfer software to analyze hippocampal subregion (subfield) volumes in patients with major depressive disorder, bipolar disorders, posttraumatic stress disorder, and other conditions, along with data from matched controls. In this overview, we explain the algorithm’s principle, summarize measurement reliability studies, and demonstrate two additional aspects (subfield autocorrelation and volume/reliability correlation) with illustrative data. We then explain the rationale for a standardized hippocampal subfield segmentation quality control (QC) procedure for improved pipeline harmonization. To guide researchers to make optimal use of the algorithm, we discuss how global size and age effects can be modelled, how QC steps can be incorporated and how subfields may be aggregated into composite volumes. This discussion is based on a synopsis of 162 published neuroimaging studies (01/2013–12/2019) that applied the FreeSurfer hippocampal subfield segmentation in a broad range of domains including cognition and healthy aging, brain development and neurodegeneration, affective disorders, schizophrenia, childhood trauma and posttraumatic stress disorder, inflammatory and systemic disease, alcoholism, stress regulation, neurotoxicity, as well as assessments of heritability, effects of candidate genes, genome-wide association studies and epigenetic effects. Lastly, we highlight points where FreeSurfer-based hippocampal subfield studies may be optimized.

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The impact of epilepsy duration in a series of patients with mesial temporal lobe epilepsy due to unilateral hippocampal sclerosis

Cited by 15 publications

References 28 publications

Are HFOs in the Intra-operative ECoG Related to Hippocampal Sclerosis, Volume and IQ?

Are HFOs in the Intra-operative ECoG Related to Hippocampal Sclerosis, Volume and IQ?

Detection of Hippocampal Subfield Asymmetry at 7T With Automated Segmentation in Epilepsy Patients With Normal Clinical Strength MRIs

FreeSurfer based segmentation of hippocampal subfields: a review of methods and applications, with a novel quality control procedure for ENIGMA studies and other collaborative efforts

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