title: Imaging foci of epileptic discharges from simultaneous EEG and fMRI using the canonical HRF.
abstract: OBJECTIVE
  Simultaneous electroencephalography and functional magnetic resonance imaging (EEG-fMRI) is considered as a powerful and non-invasive method that allows definition of the irritative zone. However, the complex interictal epileptic discharge (IED) may be present in some patients, and sometimes no active foci can be localized using General Linear Model (GLM) which is a widely adopted tool in EEG-fMRI study. The purpose of this study is to develop a new scheme to improve the detectability and localize the canonical HRF localizable foci.
  
  
  METHODS
  Various IEDs are classified using a combination of an independent component analysis (ICA) and a temporal correlation analysis between the independent components and the raw EEG channel; and the classified IEDs are then separately used for foci localization. This scheme is tested by ten patients with variable IEDs, including two patients whose activity could not be identified by common method.
  
  
  RESULTS
  Applying this scheme to the two patients, some foci consistent with electroclinical data were localized. When it was applied to the remaining eight patients with positive results using common method, 2-4 types of IEDs were classified, and the activity could be identified from at least one type of IED. The results were similar to that received from common method.
  
  
  CONCLUSIONS
  These results indicate that the proposed scheme could enhance the imaging of the localizable foci by isolating its IEDs. This scheme is potentially a useful tool for epilepsy clinic.
authors.affiliation: Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Luo
authors.forename: Zhiping
authors.initials: Z
authors.lastname: Yao
authors.forename: Qifu
authors.initials: Q
authors.lastname: Li
authors.forename: Xu
authors.initials: X
authors.lastname: Lei
authors.forename: Dong
authors.initials: D
authors.lastname: Zhou
authors.forename: Yun
authors.initials: Y
authors.lastname: Qin
authors.forename: Yang
authors.initials: Y
authors.lastname: Xia
authors.forename: Yongxiu
authors.initials: Y
authors.lastname: Lai
authors.forename: Qiyong
authors.initials: Q
authors.lastname: Gong
authors.forename: Dezhong
authors.initials: D
authors.lastname: Yao
mesh_terms: D000293:Adolescent; D002648:Child; D004569:Electroencephalography / Q000379:methods*; D004827:Epilepsy / Q000175:diagnosis* / Q000503:physiopathology*; D005260:Female; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D055815:Young Adult