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EEG–fMRI of idiopathic and secondarily generalized epilepsies

Hamandi, K.; Salek-Haddadi, A.; Laufs, H.; Liston, A.; Friston, K.; Fish, D.R.; Duncan, J.S.; (2006) EEG–fMRI of idiopathic and secondarily generalized epilepsies. NeuroImage , 31 (4) pp. 1700-1710. 10.1016/j.neuroimage.2006.02.016. Green open access

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Abstract

We used simultaneous EEG and functional MRI (EEG–fMRI) to study generalized spike wave activity (GSW) in idiopathic and secondary generalized epilepsy (SGE). Recent studies have demonstrated thalamic and cortical fMRI signal changes in association with GSW in idiopathic generalized epilepsy (IGE). We report on a large cohort of patients that included both IGE and SGE, and give a functional interpretation of our findings. Forty-six patients with GSW were studied with EEG–fMRI; 30 with IGE and 16 with SGE. GSW-related BOLD signal changes were seen in 25 of 36 individual patients who had GSW during EEG–fMRI. This was seen in thalamus (60%) and symmetrically in frontal cortex (92%), parietal cortex (76%), and posterior cingulate cortex/precuneus (80%). Thalamic BOLD changes were predominantly positive and cortical changes predominantly negative. Group analysis showed a negative BOLD response in the cortex in the IGE group and to a lesser extent a positive response in thalamus. Thalamic activation was consistent with its known role in GSW, and its detection in individual cases with EEG–fMRI may in part be related to the number and duration of GSW epochs recorded. The spatial distribution of the cortical fMRI response to GSW in both IGE and SGE involved areas of association cortex that are most active during conscious rest. Reduction of activity in these regions during GSW is consistent with the clinical manifestation of absence seizures.

Type: Article
Title: EEG–fMRI of idiopathic and secondarily generalized epilepsies
Open access status: An open access version is available from UCL Discovery
DOI: 10.1016/j.neuroimage.2006.02.016
Publisher version: http://dx.doi.org/10.1016/j.neuroimage.2006.02.016
Language: English
Keywords: EEG–fMRI, idiopathic generalized epilepsy, thalamocortical system
UCL classification: UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > UCL Queen Square Institute of Neurology > Clinical and Experimental Epilepsy
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > UCL Queen Square Institute of Neurology > Imaging Neuroscience
URI: https://discovery.ucl.ac.uk/id/eprint/20275
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