Source analysis of polyspike and wave complexes in juvenile myoclonic epilepsy

Santiago-Rodríguez, Efraín; Harmony, Thalı́a; Fernández-Bouzas, Antonio; Hernández-Balderas, Adriana; Martínez-López, Manuel; Graef, Alicia; Garcı́a, Juan Carlos; Fernández, Thalı́a

doi:10.1053/seiz.2002.0676

Cited by 29 publications

(28 citation statements)

References 17 publications

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“…In one study, asymmetry of the epileptiform discharges on scalp EEG pointed towards potentially different seizure onset as the etiology of AED resistance in patients with juvenile myoclonic epilepsy (JME), an idiopathic generalized epilepsy syndrome (11); patients with asymmetric GSWD are much more likely to have R-IGE (1, 11). Studies utilizing dipole modeling showed widespread cortical (predominantly frontal) GSWD onset in patients with IGEs (medication response not provided) (12, 13) and corroborated the evidence from morphometric studies suggestive of frontal cortical anatomical abnormalities in patients with IGEs (14, 15). Similarly, recent magneto-encephalographic (MEG) source analysis in patients with predominantly R-IGEs showed localization of the GSWD generators mainly in the central and premotor regions of the frontal lobes (16).…”

Section: Introductionsupporting

confidence: 56%

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

Szaflarski

DiFrancesco

Hirschauer

et al. 2010

Epilepsy & Behavior

120

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: Introductionsupporting

confidence: 56%

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

Szaflarski

DiFrancesco

Hirschauer

et al. 2010

Epilepsy & Behavior

120

100

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“…Source localization utilizing MEG has identified frontal lobe localizations in people with IGE (35, 36). In people with juvenile myoclonic epilepsy, spike-and-slow wave discharges were modeled to the medial prefrontal region (35). An EEG-fMRI study of a patient with IGE revealed frontal deactivation during a generalized spike-wave discharge (37).…”

Section: Discussionmentioning

confidence: 99%

Default mode network abnormalities in idiopathic generalized epilepsy

McGill¹,

Devinsky²,

Kelly³

et al. 2012

Epilepsy & Behavior

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Idiopathic Generalized Epilepsy (IGE) is associated with widespread cortical network abnormalities on electroencephalography. Resting state functional connectivity (RSFC), based on fMRI, can assess the brain’s global functional organization and its disruption in clinical conditions. We compared RSFC associated with the ‘default mode network’ (DMN) between people with IGE and healthy controls. Strength of functional connectivity within the DMN associated with seeds in the posterior cingulate cortex (PCC) and medial prefrontal cortices (MPFC) was compared between people with IGE and normal controls and was correlated with seizure duration, age of seizure onset and age at scan. Those with IGE showed markedly reduced functional network connectivity between anterior and posterior cortical seed regions. Seizure duration positively correlates with RSFC between parahippocampal gyri and the PCC but negatively correlates with connectivity between the PCC and frontal lobe. The observed pattern of disruption provides evidence for integration and segregation-type network abnormalities and supports aberrant network organization among people with IGE.

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“…A study of dipole source localization with polyspike and wave complexes in JME patients reported that the dipoles of the polyspike component are located in the medial frontal gyrus, and suggested that this region contains hyperexcitable neurons [15]. In a [ 11 C]flumazenil (FMZ) PET study, a significantly higher mean [ 11 C]FMZ volume of distribution (FMZVD) in the cerebral cortex was reported, and it was suggested that increased FMZVD could reflect microdysgenesis or a state of cortical hyperexcitability [22]. In addition, another study reported mildly increased rCBF in the superior frontal area of JME patients [26].…”

Section: Discussionmentioning

confidence: 99%