EEG‐fMRI study of the ictal and interictal epileptic activity in patients with eyelid myoclonia with absences

Liu, Yonghong; Yang, Tianhua; Liao, Wei; Yang, Xiao; Liu, Iing; Yan, Bo; Chen, Huafu; Gong, Qiyong; Stefan, Hermann; Zhou, Dong

doi:10.1111/j.1528-1167.2008.01724.x

Cited by 47 publications

(22 citation statements)

References 32 publications

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“…3 and 4) and one with frontal encephalomalacia) had EM seizures. This supports the idea of a system epilepsy that includes pathways from the occipital to the frontal cortex with discharges spreading by thalamo-cortical networks [10] as seen by the EEG-fMRI study in patients with EMA that have shown activation in the frontal regions and the thalamus [39].…”

Section: Discussionmentioning

confidence: 69%

Eyelid myoclonia seizures in adults: An alternate look at the syndrome paradox

Senol

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2015

Epilepsy & Behavior

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Section: Discussionmentioning

confidence: 69%

Eyelid myoclonia seizures in adults: An alternate look at the syndrome paradox

Senol

Tezer

Saygı

2015

Epilepsy & Behavior

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“…Activation of various brain regions during cognitive tasks has also been tested with fMRI in IGE patients . Our literature search yielded 16 fMRI studies in IGE . Despite study heterogeneity, common trends emerge from EEG‐fMRI results.…”

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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“…Only for the left thalamic seed, decreased connectivity in the cerebellum in the area of the nodule and right dentate nucleus was detected. Several studies pointed to an cerebellar involvement in IGE patients: previous EEG‐fMRI studies on GSWDs reported BOLD signal changes in the cerebellum (Gotman et al., 2005; Liu et al., 2008), a single photon emission computed tomography (SPECT) study showed reduced interictal blood flow in the cerebellum (Joo et al., 2008), and a positron emission tomography (PET) study detected an increased binding of 11 C Flumazenil binding in cerebellar nuclei in IGE patients (Savic et al., 1994). Furthermore, cerebellar ictal hyperperfusion has been described for patients with partial seizures (Bohnen et al., 1998), and stimulation of the cerebellar dentate nucleus suppressed interictal discharges and reduced the frequency of seizures in patients with intractable epilepsy (Chkhenkeli et al., 2004).…”

Section: Discussionmentioning

confidence: 99%

Functional connectivity in patients with idiopathic generalized epilepsy

et al. 2011

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SUMMARYPurpose: Idiopathic generalized epilepsy (IGE) is characterized by electroencephalography (EEG) recordings with generalized spike wave discharges (GSWDs) arising from normal background activity. Although GSWDs are the result of highly synchronized activity in the thalamocortical network, EEG without GSWDs is believed to represent normal brain activity. The aim of this study was to investigate whether thalamocortical interactions are altered even during GSWD-free EEG periods in patients with IGE. Methods: A GSWD-related group analysis was performed in 12 IGE patients to define seeds in areas involved during GSWDs. EEG-functional magnetic resonance imaging (fMRI) datasets from 22 IGE patients without GSWDs during the investigation and 30 age-matched healthy controls were then selected to investigate functional connectivity in GSWD-related areas. Blood oxygen level dependent (BOLD) signal changes were extracted from seeds defined by the GSWD-related group analysis. The averaged time course within each seed was used to detect brain regions with BOLD signal correlated with the seed. Group differences between patients and controls were estimated. Key Findings: The GSWD-related group analysis showed BOLD activation in the thalamus, the frontomesial cortex, and the cerebellum and BOLD deactivation in default mode areas. For the connectivity analysis, eight seeds were placed bilaterally in the thalamus, mesial frontal cortex, precuneus, and cerebellum. The functional connectivity analysis of these seeds did not show clearly altered functional connectivity for patients versus controls. Significance: The results underscore the paroxysmal nature of GSWDs: Although GSWDs are characterized by highly synchronized activity in the thalamocortical network, the functional connectivity in areas involved during GSWDs does not demonstrate abnormality in GSWD-free periods.

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EEG‐fMRI study of the ictal and interictal epileptic activity in patients with eyelid myoclonia with absences

Cited by 47 publications

References 32 publications

Eyelid myoclonia seizures in adults: An alternate look at the syndrome paradox

Eyelid myoclonia seizures in adults: An alternate look at the syndrome paradox

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

Functional connectivity in patients with idiopathic generalized epilepsy

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