Electrical activity of subcortical areas in epilepsy

Hayne, Robert A.; Belinson, Louis; Gibbs, Frederic A.

doi:10.1016/0013-4694(49)90215-1

Cited by 71 publications

(11 citation statements)

References 11 publications

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“…While the thalamus, with its connections to all areas of the cortex and its baseline rhythmic firing of bursts of action potentials appears to be an important, if not the most important part of the network underlying GSWD generation, evidence suggests that there may be cortical sources contributing to the etiology of IGEs (54). This notion is consistent with the early human epilepsy literature focusing on cortical onset as the main source of generalized epileptic seizures (41, 55). Certainly, our findings in patients with R-IGEs are in agreement with the cortical theory of generalized absence seizure onset (43, 44).…”

Section: Discussionsupporting

confidence: 91%

“…An invasive study by Williams led Penfield and Jasper to propose the centrencephalic theory, which posits the thalamus and the upper brain stem as the origin of GSWD in generalized epilepsies (39, 40). Other invasive studies did not confirm these findings (41, 42). In fact, the study by Niedermeyer et al indicated that patients with similar phenotypes suggestive of generalized epilepsy might have had different sources of the GSWD leading to different responses to antiepileptic drugs; at least two of his patients with a typical IGE phenotype proved to have frontal lobe epilepsy; one of them became seizure-free after surgical intervention (41).…”

Section: Discussionmentioning

confidence: 78%

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Cortical and subcortical contributions to absence seizure onset examined with EEG/fMRI

Szaflarski

DiFrancesco

Hirschauer

et al. 2010

Epilepsy & Behavior

121

100

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In patients with idiopathic generalized epilepsies (IGE), bursts of generalized spike and wave discharges (GSWD) lasting ≥2 seconds are considered absence seizures. The location of the absence seizures generators in IGEs is thought to involve interplay between various components of thalamo-cortical circuits; we have recently postulated that medication resistance may, in part, be related to the location of the GSWD generators (1). In the present study we hypothesized that patients with medication-refractory IGE (R-IGE) and continued absence seizures may have location of the GSWD generators other than the thalamus, as typically seen in the IGE patients. Hence, the objective of this study was to determine the location of the GSWD generators in patients with R-IGE using EEG/fMRI. 83 patients with IGE received concurrent EEG/fMRI at 4T. Nine of them (ages 15-55) experienced absence seizures during EEG/fMRI and were included; all were diagnosed with R-IGE. Subjects participated in up to three 20-minute EEG/fMRI sessions (400 volumes; TR = 3 seconds) performed at 4T. After removing fMRI and ballistocardiographic artifacts, 36 absence seizures were identified. Statistical parametric maps were generated for each of these sessions correlating seizures to BOLD response. Timing differences between brain regions were tested using statistical parametric maps generated by modeling seizures with onset times shifted relative to the GSWD onsets. While thalamic BOLD responses peaked at approximately 6 seconds after the onset of absence seizures, other areas including the prefrontal and dorsolateral cortices showed brief and non-sustained peaks occurring ~2 seconds prior to the maximum of the thalamic peak. Temporal lobe peaks occurred at the same time as the thalamic peak with a cerebellar peak occurring ~1 second later. Confirmatory analysis averaging cross

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Section: Discussionsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 78%

Cortical and subcortical contributions to absence seizure onset examined with EEG/fMRI

Szaflarski

DiFrancesco

Hirschauer

et al. 2010

Epilepsy & Behavior

121

100

View full text Add to dashboard Cite

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“…As known, signals recorded simultaneously from the surface and the depth of the brain with a common reference electrode show polarity reversal (Freeman, 1978; Coenen, 1995). The same polarity reversal was found in petit mal patients (Hayne et al, 1949) and likely to reflect an opposite orientation of electrical currents formed by the superficial and deep neural mass (Lopes da Silva and van Rotterdam, 1982).…”

Section: Discussionsupporting

confidence: 54%

Electroencephalographic Characterization of Spike‐Wave Discharges in Cortex and Thalamus in WAG/Rij Rats

Sitnikova

Luijtelaar

2007

Epilepsia

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Spike-and-wave complexes are stereotypic reproducible electroencephalographic patterns that accompany different forms of idiopathic generalized epileptic syndromes such as childhood absence epilepsy, juvenile absence epilepsy, juvenile myoclonic epilepsy, myoclonic absence epilepsy, and eyelid myoclonia with absences (Gibbs et al., 1935;Panayiotopoulos, 1999Panayiotopoulos, , 2005. Spike-and-wave complexes are regular and symmetrical generalized discharges of 2.5-4 Hz. The Committee on Terminology of the International Federation of Societies for Electroencephalography and Clinical Neurophysiology (IFSECN) defines spikeand-slow-wave complex as "a pattern consisting of a spike followed by a slow wave" (3). However, more than 40 years ago, Weir (1965) defined four epileptiform elements in

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“…In a case series of four patients with GSWD on scalp EEG, depth electrode records demonstrated focal frontal onset in two . Another depth electrode study in patients with generalized seizures revealed cortical onset of GSWD . With stereo‐EEG implanted in 10 patients, Bancaud et al .…”

Section: Resultsmentioning

confidence: 99%

Focal abnormalities in idiopathic generalized epilepsy: A critical review of the literature

2014

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SUMMARYConventionally, epilepsy is dichotomized into distinct "focal" and "generalized" categories. However, many studies have reported so-called focal features among patients with idiopathic generalized epilepsy (IGE) in the domains of semiology, electroencephalography, neuropsychology, neuropathology, and neuroimaging. We sought to review such features and clinical implications. A Web of Science database search was conducted to identify relevant publications. Our search yielded 145 papers describing focal features involving different domains in IGE, with 117 papers analyzed after excluding abstracts and case reports. Focal semiologic features are commonly seen in IGE. There are conflicting data from studies in the domains of electroencephalography, neuroimaging, and neuropathology. Studies on neuropsychology are suggestive of frontal lobe functional deficits in juvenile myoclonic epilepsy. Most advanced neuroimaging studies demonstrate the involvement of both the thalamus and the cortex during generalized spike-wave discharges (GSWDs). A few electroencephalographic and neuroimaging studies indicate that the cortex precedes the thalamus at the onset of GSWD. Focal features may contribute to misdiagnosis of IGE as focal epilepsy. However there are methodologic limitations in the studies that affect the results. KEY WORDS: Electroencephalographic, Epilepsy semiology, Generalized seizures, Partial seizures, Neuroimaging, Neuropsychology.Idiopathic generalized epilepsy (IGE; genetic generalized epilepsy) constitutes a rubric of several electroclinical syndromes based on specific clinical features and electroencephalography (EEG) abnormalities.1,2 The traditional approach of classifying epilepsies into "focal" and "generalized" implies there can be no "focal" features in "generalized" epilepsies. However, there has been a gradual paradigm shift in the conceptualization of seizure generation and spread based on epileptic networks. This change is reflected in a recent publication by the International League Against Epilepsy (ILAE) on revised terminology of seizures and epilepsies.2 This paper conceptualizes focal seizures as those arising from networks confined to a single cerebral hemisphere, whereas generalized seizures "originate at some point within, and rapidly engage bilaterally distributed networks" including cortical and subcortical structures, leaving open the possibility of a focal origin within the network.Amid the ongoing debate and discussion about the pathogenesis and classification of IGE, a body of literature highlighting various focal features of IGE has gradually accumulated over the years. In this paper, we review the literature on focal characteristics of IGE in the domains of semiology, EEG, neuropsychology, neuropathology, and neuroimaging.

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Electrical activity of subcortical areas in epilepsy

Cited by 71 publications

References 11 publications

Cortical and subcortical contributions to absence seizure onset examined with EEG/fMRI

Cortical and subcortical contributions to absence seizure onset examined with EEG/fMRI

Electroencephalographic Characterization of Spike‐Wave Discharges in Cortex and Thalamus in WAG/Rij Rats

Focal abnormalities in idiopathic generalized epilepsy: A critical review of the literature

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