Pivotal Role of Subcortical Structures as a Network Hub in Focal Epilepsy: Evidence from Graph Theoretical Analysis Based on Diffusion-Tensor Imaging

Park, Kang Min; Lee, Ki Young; Shin, Kyoungsoon; Ha, Sam Yeol; Park, Jinse; Kim, Si Eun; Kim, Sung Eun

doi:10.3988/jcn.2019.15.1.68

Cited by 37 publications

(41 citation statements)

References 41 publications

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“…There have been several studies showing involvement of the thalamus in patients with TLE with HS, with potential roles in seizure initiation and propagation [25][26][27]. The hippocampus has important reciprocal connections to the thalamus [28].…”

Section: Discussionmentioning

confidence: 99%

Intrinsic hippocampal and thalamic networks in temporal lobe epilepsy with hippocampal sclerosis according to drug response

Lee

Park

2020

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The aim of this study was to investigate whether intrinsic hippocampal or thalamic networks in patients with temporal lobe epilepsy (TLE) with hippocampal sclerosis (HS) were different according to antiepileptic drug (AED) response. Methods: We enrolled 80 patients with TLE with HS and 40 healthy controls. Of the patients with TLE with HS, 43 were classified as a drug-resistant epilepsy (DRE) group, whereas 37 patients were enrolled as a drug-controlled epilepsy (DCE) group. We investigated the structural connectivity of the global brain, intrinsic hippocampal, and intrinsic thalamic networks based on structural volumes in the patients with DRE and DCE, and analyzed the differences between them. Results: There were significant alterations of the intrinsic hippocampal network compared with healthy controls. The average degree and the global efficiency were decreased, whereas the characteristic path length was increased in the patients with DRE compared with those in healthy controls. In the patients with DCE, only the small-worldness index was decreased compared with healthy controls. Compared to the patients with DCE, the mean clustering coefficient was increased in the patients with DRE. Conclusion:We found that the intrinsic hippocampal network in patients with TLE with HS was different according to AED response. The patients with DRE had more severe disruptions of the intrinsic hippocampal network than those with DCE compared with healthy controls. These findings suggested that the hippocampal network might be related to AED response and could be a new biomarker of medical outcome in patients with TLE with HS.

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Section: Discussionmentioning

confidence: 99%

Intrinsic hippocampal and thalamic networks in temporal lobe epilepsy with hippocampal sclerosis according to drug response

Lee

Park

2020

Seizure

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“…Moreover, subcortical-cortical connectivity was shown to be altered in different epilepsy types. 19,20 When surgery is contraindicated or unsuccessful, deep brain stimulation (DBS) targeting thalamic nuclei can be an option (for a review see 21 ) but the mechanisms of corticosubcortical interactions during seizures are mostly unknown and it is unclear which type of epilepsy is best suited to such a treatment. The aims of this work were to evaluate thalamic and other subcortical nuclei participation in epileptogenic networks and to estimate the correlation of thalamic activity with clinical data and post-surgical outcome.…”

Section: Introductionmentioning

confidence: 99%

The Ictal Signature of Thalamus and Basal Ganglia in Focal Epilepsy

et al. 2021

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ObjectiveTo determine the involvement of subcortical regions in human epilepsy by analyzing direct recordings from these regions during epileptic seizures using stereoelectroencephalography (SEEG).Methodswe studied the SEEG recordings of a large series of patients (74 patients, 157 seizures) with an electrode sampling the thalamus and in some cases also the basal ganglia (caudate nucleus −22 patients- and putamen—4 patients). We applied visual analysis and signal quantification methods (Epileptogenicity Index, EI) to their ictal recordings and compared electrophysiologic with clinical data.ResultsWe found that in 86% of patients thalamus was involved during seizures (visual analysis) and that 20% showed high values of epileptogenicity (EI >0.3). Basal ganglia may also disclose high values of epileptogenicity (9% in caudate nucleus) but to a lesser degree than thalamus (p < 0.01). We observed different seizure onset patterns including low voltage high frequency activities. We found high values of thalamic epileptogenicity in different epilepsy localisations, including opercular and motor epilepsies. We found no difference between epilepsy aetiologies (cryptogenic vs malformation of cortical development, p = 0.77). Thalamic epileptogenicity was correlated with the extension of epileptogenic networks (p = 0.03, ρ 0.32). We found a significant effect (p < 0.05) of thalamic epileptogenicity regarding the post-surgical outcome (higher thalamic EI corresponding to higher probability of surgical failure).ConclusionsThalamic involvement during seizures is common in different seizure types. The degree of thalamic epileptogenicity is a possible marker of the epileptogenic network extension and of post-surgical prognosis.

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“…Epilepsy is considered a disorder of neural networks (7). Neural networks involved in seizure generation, maintenance and spread of epileptic activity comprise cortico-subcortical circuits (8,9). Subcortical structures, such as white matter, are involved in epileptic activities.…”

Section: Introductionmentioning

confidence: 99%

Altered White Matter Structural Network in Frontal and Temporal Lobe Epilepsy: A Graph-Theoretical Study

et al. 2020

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Temporal lobe epilepsy (TLE) and frontal lobe epilepsy (FLE) are the largest subgroup of partial epilepsy, and focal cortical dysplasias (FCDs) are highly epileptogenic brain lesions and are a frequent cause for antiepileptic drug (AED)-resistant focal epilepsies that mostly occur in the temporal and frontal lobes. We performed a graph-theoretical study based on the diffusion tensor imaging (DTI) data of patients with FLE or TLE caused by FCDs or lesions with high suspicion of FCDs and evaluated their cognitive function by the Chinese version of the Montreal Cognitive Assessment-Basic (MoCA-BC). The construction of the white matter structural network and graph-theoretical analysis was performed by Pipeline for Analysing Brain Diffusion Images (PANDA) and Graph-theoretical Network Analysis (GRETNA). We used the nonparametric analysis of covariance to compare the differences in diffusion metrics, network attributes and nodal attributes among FLE, TLE, and healthy control (HC) groups and then performed post hoc pairwise comparisons. Nonparametric Spearman partial correlation analysis was performed to analyse the correlation of network attributes with the age of onset, duration of disease, and MoCA-BC scores in patients with FLE and TLE. The results showed that the white matter structural network in patients with FLE and TLE was impaired in a more extensive set of regions than the FCD location. The similarities in white matter alterations between FLE and TLE suggested that their epileptogenic network might affect the fronto-temporal white matter tracts and thalamo-occipital connections, which might be responsible for the overlapping cognitive deficits in FLE and TLE. The white matter impairments in patients with FLE were more severe than those in patients with TLE, which might be explained by more affected nodes in the areas of DMN in patients with FLE.

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Pivotal Role of Subcortical Structures as a Network Hub in Focal Epilepsy: Evidence from Graph Theoretical Analysis Based on Diffusion-Tensor Imaging

Cited by 37 publications

References 41 publications

Intrinsic hippocampal and thalamic networks in temporal lobe epilepsy with hippocampal sclerosis according to drug response

Intrinsic hippocampal and thalamic networks in temporal lobe epilepsy with hippocampal sclerosis according to drug response

The Ictal Signature of Thalamus and Basal Ganglia in Focal Epilepsy

Altered White Matter Structural Network in Frontal and Temporal Lobe Epilepsy: A Graph-Theoretical Study

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