Ictal spread of medial temporal lobe seizures with and without secondary generalization: An intracranial electroencephalography analysis

Yoo, Ji Yeoun; Farooque, Pue; Chen, William; Youngblood, Mark W.; Zaveri, Hitten P.; Gerrard, Jason L.; Spencer, Dennis D.; Hirsch, Lawrence J.; Blumenfeld, Hal

doi:10.1111/epi.12505

Cited by 46 publications

(34 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Interestingly, the difference between groups 1 and 2 could depend on how seizures propagate. Although purely speculative, it might be possible that, in the case of secondarily generalized seizures, the ictal activity might propagate more rapidly or has a larger focal region (43), and this would result in a shorter duration of the focal isolation. For patients who had partial seizures without secondary generalization and who had previous resective surgeries (group 3), instead, we could not consistently identify any time period with the seizure onset zone isolated or strongly connected.…”

Section: Discussionmentioning

confidence: 99%

Network dynamics of the brain and influence of the epileptic seizure onset zone

Burns¹,

Santaniello²,

Yaffe

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

263

247

View full text Add to dashboard Cite

The human brain is a dynamic networked system. Patients with partial epileptic seizures have focal regions that periodically diverge from normal brain network dynamics during seizures. We studied the evolution of brain connectivity before, during, and after seizures with graph-theoretic techniques on continuous electrocorticographic (ECoG) recordings (5.4 ± 1.7 d per patient, mean ± SD) from 12 patients with temporal, occipital, or frontal lobe partial onset seizures. Each electrode was considered a node in a graph, and edges between pairs of nodes were weighted by their coherence within a frequency band. The leading eigenvector of the connectivity matrix, which captures network structure, was tracked over time and clustered to uncover a finite set of brain network states. Across patients, we found that (i) the network connectivity is structured and defines a finite set of brain states, (ii) seizures are characterized by a consistent sequence of states, (iii) a subset of nodes is isolated from the network at seizure onset and becomes more connected with the network toward seizure termination, and (iv) the isolated nodes may identify the seizure onset zone with high specificity and sensitivity. To localize a seizure, clinicians visually inspect seizures recorded from multiple intracranial electrode contacts, a time-consuming process that may not always result in definitive localization. We show that network metrics computed from all ECoG channels capture the dynamics of the seizure onset zone as it diverges from normal overall network structure. This suggests that a state space model can be used to help localize the seizure onset zone in ECoG recordings.focal epilepsy | seizure localization | network analysis | eigenvector centrality | ECoG signals E pilepsy affects over 60 million people worldwide, and approximately 40% of patients have drug-resistant epilepsy (DRE) with recurrent seizures that are not controlled by available medications (1-3). It is now routine to consider drugresistant partial epilepsy patients, who represent the largest cohort of patients with uncontrolled seizures, for possible resective seizure surgery (4). Successful seizure surgery is predicated upon the ability to localize the seizure onset zone. Although some patients (e.g., those with mesial temporal sclerosis or lesional epilepsy) can proceed to surgery following scalp recordings of seizures delineating a seizure onset zone (5), a significant number of patients have seizures that are challenging to localize with scalp ictal (i.e., seizure) recordings. In this case, ictal recordings using intracranial electrodes (e.g., subdural strips, grids, or depth electrode arrays) are necessary. The purpose of these intracranial recording arrays is to provide information about seizure onset and propagation, representing spatiotemporal changes in cerebral function.Using intracranial electrocorticographic (ECoG) recordings taken over several days to capture ictal events, clinicians visually inspect the ECoG recordings at the onset of the seizures an...

show abstract

Section: Discussionmentioning

confidence: 99%

Network dynamics of the brain and influence of the epileptic seizure onset zone

Burns¹,

Santaniello²,

Yaffe

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

263

247

View full text Add to dashboard Cite

show abstract

“…Temporal lobe epilepsy, for example, is postulated to be a disorder of the limbic system (Bartolomei et al, 2001;Bonilha et al, 2012;Spencer, 2002), and seizure disorders are increasingly conceptualized as network disorders (Blumenfeld, 2014;Stefan and Lopes da Silva, 2013). Seizures originating in temporal sites have been shown to spread along established axonal pathways (Mraovitch and Calando, 1999;Yoo et al, 2014), allowing the seizure activity to propagate to subcortical arousal nuclei necessary for cortical activation. Our identification of a human LFB thus provides a putative pathway by which temporal lobe seizures may cause dysfunction within brainstem arousal nuclei, with subsequent inhibition of the cerebral cortex and impaired consciousness (Blumenfeld, 2012).…”

Section: Human Central Homeostatic Network 195 Discussionmentioning

confidence: 99%

The Structural Connectome of the Human Central Homeostatic Network

et al. 2016

View full text Add to dashboard Cite

Homeostatic adaptations to stress are regulated by interactions between the brainstem and regions of the forebrain, including limbic sites related to respiratory, autonomic, affective, and cognitive processing. Neuroanatomic connections between these homeostatic regions, however, have not been thoroughly identified in the human brain. In this study, we perform diffusion spectrum imaging tractography using the MGH-USC Connectome MRI scanner to visualize structural connections in the human brain linking autonomic and cardiorespiratory nuclei in the midbrain, pons, and medulla oblongata with forebrain sites critical to homeostatic control. Probabilistic tractography analyses in six healthy adults revealed connections between six brainstem nuclei and seven forebrain regions, several over long distances between the caudal medulla and cerebral cortex. The strongest evidence for brainstem-homeostatic forebrain connectivity in this study was between the brainstem midline raphe and the medial temporal lobe. The subiculum and amygdala were the sampled forebrain nodes with the most extensive brainstem connections. Within the human brainstem-homeostatic forebrain connectome, we observed that a lateral forebrain bundle, whose connectivity is distinct from that of rodents and nonhuman primates, is the primary conduit for connections between the brainstem and medial temporal lobe. This study supports the concept that interconnected brainstem and forebrain nodes form an integrated central homeostatic network (CHN) in the human brain. Our findings provide an initial foundation for elucidating the neuroanatomic basis of homeostasis in the normal human brain, as well as for mapping CHN disconnections in patients with disorders of homeostasis, including sudden and unexpected death, and epilepsy.

show abstract

“…Our SEEG study also confirmed that, even in patients with OAAs, the amygdala was often involved in other types of seizures, including sensory seizures. 22 The amygdala may be closely related to the production of fear aura. Maestro et al 10 induced OAAs by cortical electrical stimulation of the frontoopercular cortex that were distant from the SOZ and were not involved in seizure propagation.…”

Section: The Symptomatogenic Zone Of Oaasmentioning

confidence: 99%

Symptomatogenic zone and network of oroalimentary automatisms in mesial temporal lobe epilepsy

Wang

et al. 2019

Epilepsia

View full text Add to dashboard Cite

Objective Oroalimentary automatisms (OAAs) are common clinical manifestations of medial temporal lobe epilepsy. Nevertheless, the location of the symptomatogenic zone of OAAs remains unclear. The generation mechanism of OAAs also has not been clarified. We attempt to explain these problems by analyzing interictal [18F]‐fluorodeoxyglucose positron emission tomography (18FDG‐PET) imaging and ictal stereo‐electroencephalography (SEEG) recordings in patients with medial temporal lobe epilepsy. Methods Fifty‐seven patients with mesial temporal lobe epilepsy were analyzed retrospectively. All underwent anterior temporal lobectomy (ATL) and were seizure‐free. The patients were divided into OAA (+) and OAA (−) groups according to the occurrence of consistent stereotyped OAAs. The interictal PET data were compared with those of 18 healthy controls and were then compared between groups using statistical parametric mapping (SPM). Functional connectivity using linear regression analysis was performed between the target brain regions. To clarify the network of OAAs, ictal epileptogenicity index (EI) values, and the nonlinear correlation method h2 were performed with SEEG on patients. Results Compared to OAAs (−), the rolandic operculum was the only area with significant differences. Hippocampus and rolandic operculum showed significant correlations in the OAA (+) group (y = 0.758x+0.470, R2 = 0.456, P = 0.000). No correlation was found in the OAA (−) group (P = 0.486). The EI values of the OAA (+) group (median 0.20) were significantly higher (P < 0.0001) than those of the OAA (−) group (median 0). The h2 in the OAA (+) group (h2 = 0.23 ± 0.13) showed stronger functional connectivity (t = 6.166, P < 0.0001) than that of the OAA (−) group (h2 = 0.08 ± 0.05). Significance The rolandic operculum is most likely to be the symptomatogenic zone of OAAs. In medial temporal lobe epilepsy, unilateral functional connection from the hippocampus to the rolandic operculum during seizure onset is the basis for the generation of OAAs.

show abstract

Ictal spread of medial temporal lobe seizures with and without secondary generalization: An intracranial electroencephalography analysis

Cited by 46 publications

References 29 publications

Network dynamics of the brain and influence of the epileptic seizure onset zone

Network dynamics of the brain and influence of the epileptic seizure onset zone

The Structural Connectome of the Human Central Homeostatic Network

Symptomatogenic zone and network of oroalimentary automatisms in mesial temporal lobe epilepsy

Contact Info

Product

Resources

About