OBJECTIVE: Studies of absence seizures (AS) using EEG with fMRI (EEG-fMRI) show a consistent network with prominent thalamic activation and a variety of cortical changes. Despite evidence suggesting a role of frontal cortex in seizure generation, group studies have not detected consistent AS-related changes in this region. We hypothesized that only a subgroup may show frontal cortical activation. METHOD: We studied 13 subjects with AS during EEG-fMRI to classify the different individual patterns of frontal cortical activation associated with AS. RESULTS: Based upon visual inspection of surface-rendered activation maps we identified 2 subgroups that could be distinguished by the activation in the dorsolateral prefrontal cortex (DLPFC). One group of patients (n = 7) showed a primarily positive signal change (DLPFC-POS), whereas the other group (n = 6) showed a primarily negative signal change (DLFPC-NEG). When the DLPFC-POS group was compared to the DLPFC-NEG group, time-course analysis revealed a larger positive blood oxygenation level-dependent deflection following onset of the AS in cortical and subcortical areas beyond the DLPFC. This suggests a basic biological difference between these groups. CONCLUSION: These observations suggest that there may be at least 2 mechanisms underpinning AS in individuals with absence epilepsy. This may have phenotypic and genetic implications for understanding epilepsy syndromes.
OBJECTIVE: Studies of absence seizures (AS) using EEG with fMRI (EEG-fMRI) show a consistent network with prominent thalamic activation and a variety of cortical changes. Despite evidence suggesting a role of frontal cortex in seizure generation, group studies have not detected consistent AS-related changes in this region. We hypothesized that only a subgroup may show frontal cortical activation. METHOD: We studied 13 subjects with AS during EEG-fMRI to classify the different individual patterns of frontal cortical activation associated with AS. RESULTS: Based upon visual inspection of surface-rendered activation maps we identified 2 subgroups that could be distinguished by the activation in the dorsolateral prefrontal cortex (DLPFC). One group of patients (n = 7) showed a primarily positive signal change (DLPFC-POS), whereas the other group (n = 6) showed a primarily negative signal change (DLFPC-NEG). When the DLPFC-POS group was compared to the DLPFC-NEG group, time-course analysis revealed a larger positive blood oxygenation level-dependent deflection following onset of the AS in cortical and subcortical areas beyond the DLPFC. This suggests a basic biological difference between these groups. CONCLUSION: These observations suggest that there may be at least 2 mechanisms underpinning AS in individuals with absence epilepsy. This may have phenotypic and genetic implications for understanding epilepsy syndromes.
Authors: Neelan Pillay; John S Archer; Radwa A B Badawy; Danny F Flanagan; Samuel F Berkovic; Graeme Jackson Journal: Neurology Date: 2013-07-17 Impact factor: 9.910
Authors: Prince Antwi; Ece Atac; Jun Hwan Ryu; Christopher Andrew Arencibia; Shiori Tomatsu; Neehan Saleem; Jia Wu; Michael J Crowley; Barbara Banz; Federico E Vaca; Heinz Krestel; Hal Blumenfeld Journal: Epilepsy Behav Date: 2018-12-21 Impact factor: 2.937