Does the patient's hand hold the key to preventing secondary generalization in mesial temporal lobe epilepsy?

Uchida, Carina Gonçalves Pedroso; Barsottini, Orlando Graziani Póvoas; Caboclo, Luís Otávio Sales Ferreira; Filho, Gerardo Maria de Araújo; Centeno, Ricardo Silva; Carrete, Henrique; Yacubian, Elza Márcia Targas

doi:10.1016/j.eplepsyres.2013.02.001

Cited by 4 publications

(2 citation statements)

References 42 publications

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“…The BG is increasingly hypothesised to play an anticonvulsive role in FBTCS 12 , yet specific mechanisms remain unclear. Increased BG activity was reported to be negatively associated with FBTCS in TLE 13,14 . In contrast, others illustrated that the BG only become involved when ictal activity disperses to additional cortical regions during secondary generalisation 15 .…”

Section: Introductionmentioning

confidence: 97%

White matter alterations in focal to bilateral tonic-clonic seizures

Maher

D’Souza

Zeng

et al. 2021

Preprint

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Objective: A better understanding of the mechanistic underpinnings of focal to bilateral tonic-clonic seizures (FBTCS) would aid treatment decisions, and improve disease management for drug-refractory patients. We sought to examine the microstructural white matter differences in patients with FBTCS, compared to those with focal epilepsy without FBTCS, and control participants. Methods: We combined a superior tract segmentation model with track-weighted tensor metrics (TW-TM) in an advanced, automated image analysis and tract reconstruction pipeline. Univariate analysis of covariance (ANCOVA) tests were used to compare group differences in both whole-tract metrics and hemispheric tract metrics. Results: We identified a range of white matter regions that displayed significantly altered white matter in patients with and without FBTCS, compared to controls. Specifically, patients without FBTCS had significantly increased white matter disruption in the inferior fronto-occipital fascicle and the striato-occipital tract. In contrast, patients with FBTCS were more similar to healthy controls in most regions, except for distinct alterations in the inferior cerebellar region compared to the non-FBTCS group and controls. Significance: This study exploited track-weighted tensor metrics (TW-TM) to investigate white matter changes in FBTCS. Our findings revealed marked alterations in a range of subcortical regions widely considered critical in the genesis of seizures. Our application of TW-TM in a new clinical dataset allowed the identification of specific tracts that may act as a predictive biomarker to distinguish patients who are likely to develop FBTCS.

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Section: Introductionmentioning

confidence: 97%

White matter alterations in focal to bilateral tonic-clonic seizures

Maher

D’Souza

Zeng

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…The basal ganglia are increasingly hypothesized to play an anticonvulsive role in FBTCS ( 12 ), yet the specific mechanisms remain unclear. Increased basal ganglia activity was reported to be negatively associated with FBTCS in TLE ( 13 , 14 ). In contrast, others illustrated that the basal ganglia only become involved when ictal activity disperses to additional cortical regions during secondary generalization ( 15 ).…”

Section: Introductionmentioning

confidence: 99%

White matter alterations in focal to bilateral tonic-clonic seizures

et al. 2022

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We examined the white matter of patients with and without focal to bilateral tonic-clonic seizures (FBTCS), and control participants. A neural network based tract segmentation model (Tractseg) was used to isolate tract-specific, track-weighted tensor-based measurements from the tracts of interest. We compared the group differences in the track-weighted tensor-based measurements derived from whole and hemispheric tracts. We identified several regions that displayed significantly altered white matter in patients with focal epilepsy compared to controls. Furthermore, patients without FBTCS showed significantly increased white matter disruption in the inferior fronto-occipital fascicle and the striato-occipital tract. In contrast, the track-weighted tensor-based measurements from the FBTCS cohort exhibited a stronger resemblance to the healthy controls (compared to the non-FBTCS group). Our findings revealed marked alterations in a range of subcortical tracts considered critical in the genesis of seizures in focal epilepsy. Our novel application of tract-specific, track-weighted tensor-based measurements to a new clinical dataset aided the elucidation of specific tracts that may act as a predictive biomarker to distinguish patients likely to develop FBTCS.

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Disrupted basal ganglia–thalamocortical loops in focal to bilateral tonic-clonic seizures

Chaitanya

Asma

et al. 2019

Brain

105

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Focal to bilateral tonic-clonic seizures are associated with lower quality of life, higher risk of seizure-related injuries, increased chance of sudden unexpected death, and unfavourable treatment outcomes. Achieving greater understanding of their underlying circuitry offers better opportunity to control these seizures. Towards this goal, we provide a network science perspective of the interactive pathways among basal ganglia, thalamus and cortex, to explore the imprinting of secondary seizure generalization on the mesoscale brain network in temporal lobe epilepsy. Specifically, we parameterized the functional organization of both the thalamocortical network and the basal ganglia–thalamus network with resting state functional MRI in three groups of patients with different focal to bilateral tonic-clonic seizure histories. Using the participation coefficient to describe the pattern of thalamocortical connections among different cortical networks, we showed that, compared to patients with no previous history, those with positive histories of focal to bilateral tonic-clonic seizures, including both remote (none for >1 year) and current (within the past year) histories, presented more uniform distribution patterns of thalamocortical connections in the ipsilateral medial-dorsal thalamic nuclei. As a sign of greater thalamus-mediated cortico-cortical communication, this result comports with greater susceptibility to secondary seizure generalization from the epileptogenic temporal lobe to broader brain networks in these patients. Using interregional integration to characterize the functional interaction between basal ganglia and thalamus, we demonstrated that patients with current history presented increased interaction between putamen and globus pallidus internus, and decreased interaction between the latter and the thalamus, compared to the other two patient groups. Importantly, through a series of ‘disconnection’ simulations, we showed that these changes in interactive profiles of the basal ganglia–thalamus network in the current history group mainly depended upon the direct but not the indirect basal ganglia pathway. It is intuitively plausible that such disruption in the striatum-modulated tonic inhibition of the thalamus from the globus pallidus internus could lead to an under-suppressed thalamus, which in turn may account for their greater vulnerability to secondary seizure generalization. Collectively, these findings suggest that the broken balance between basal ganglia inhibition and thalamus synchronization can inform the presence and effective control of focal to bilateral tonic-clonic seizures. The mechanistic underpinnings we uncover may shed light on the development of new treatment strategies for patients with temporal lobe epilepsy.

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Does the patient's hand hold the key to preventing secondary generalization in mesial temporal lobe epilepsy?

Cited by 4 publications

References 42 publications

White matter alterations in focal to bilateral tonic-clonic seizures

White matter alterations in focal to bilateral tonic-clonic seizures

White matter alterations in focal to bilateral tonic-clonic seizures

Disrupted basal ganglia–thalamocortical loops in focal to bilateral tonic-clonic seizures

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