title: EEG-fMRI study on the interictal and ictal generalized spike-wave discharges in patients with childhood absence epilepsy.
abstract: BACKGROUND
  Absence epilepsy is characterized clinically by the impairment of consciousness and 3 Hz generalized spike-wave discharges (GSWDs) on EEG. Clinical absence can be observed with ictal GSWDs, but interictal GSWD bursts are usually clinically silent. Simultaneous EEG and blood-oxygen-level-dependent (BOLD) functional MRI (EEG-fMRI) has been successfully used to link the changes in regional neuronal activity to the occurrence of GSWDs.
  
  
  METHODS
  We used EEG-fMRI to investigate and compare the BOLD signal changes during interictal and ictal GSWDs in patients with childhood absence epilepsy (CAE).
  
  
  RESULTS
  Fifteen drug-naïve children with newly diagnosed CAE were studied using continuous EEG-fMRI. BOLD signal changes associated with interictal (nine sessions with six patients) and ictal (eight sessions with six patients) GSWDs were analyzed at the individual and group levels. GSWDs were associated with widespread and symmetrical deactivation in the cortex and caudate nucleus with a frontal maximum, and predominant activation in the thalamus bilaterally during ictal GSWDs and in the cortex during interictal GSWDs. The BOLD response was characterized by a higher statistical significance and a more widespread extent at the time of the ictal GSWDs as compared to the time of interictal GSWDs.
  
  
  CONCLUSIONS
  Both interictal and ictal GSWDs in patients with CAE are associated with BOLD signal changes in the basal ganglia-thalamocortical loop. Ictal GSWDs showing predominant thalamic activation and widespread cortical deactivation might cause a complete suspension of the normal brain's default state and manifest clinically as abrupt loss of consciousness (absence seizures).
authors.affiliation: Department of Neurology, West China Hospital of Sichuan University, Chengdu, Sichuan Province, PR China.
authors.forename: Qifu
authors.initials: Q
authors.lastname: Li
authors.forename: Cheng
authors.initials: C
authors.lastname: Luo
authors.forename: Tianhua
authors.initials: T
authors.lastname: Yang
authors.forename: Zhiping
authors.initials: Z
authors.lastname: Yao
authors.forename: Li
authors.initials: L
authors.lastname: He
authors.forename: Ling
authors.initials: L
authors.lastname: Liu
authors.forename: Hongru
authors.initials: H
authors.lastname: Xu
authors.forename: Qiyong
authors.initials: Q
authors.lastname: Gong
authors.forename: Dezhong
authors.initials: D
authors.lastname: Yao
authors.forename: Dong
authors.initials: D
authors.lastname: Zhou
mesh_terms: D000293:Adolescent; D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D004569:Electroencephalography; D004832:Epilepsy, Absence / Q000175:diagnosis / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D009415:Nerve Net / Q000503:physiopathology; D009474:Neurons / Q000502:physiology; D011446:Prospective Studies