Analysis of Ictal EEG of Neocortical Epilepsy by Independent Component Analysis.
Abstract number :
1.076
Submission category :
Year :
2001
Submission ID :
166
Source :
www.aesnet.org
Presentation date :
12/1/2001 12:00:00 AM
Published date :
Dec 1, 2001, 06:00 AM
Authors :
H. Nam, M.D., Ph.D., Neurology, Seoul Municipal Boramae Hospital, Seoul, Korea; T-G. Yim, Physics, Chungbuk National University, Cheongju, Korea; S.K. Han, Ph.D., Physics, Chungbuk National University, Cheongju, Korea; J-B. Oh, M.D., Neurology, Seoul Nati
RATIONALE: Independent component analysis (ICA) has been successfully applied to various fields including ERP and interictal EEG analyses. As a result, extracting components of interest and removing artifacts were possible. However, this method has not been applied to the ictal EEG. Our current study is to estimate the usefulness of ICA in the analysis of neocortical ictal EEG.
METHODS: Subjects were 18 ictal EEGs from 6 lateral temporal lobe epilepsy (TLE) patients and 43 ictal EEGs from 10 occipital lobe epilepsy (OLE) patients. Digital EEG signal was recorded according to the international 10-20 system with additional T1 and T2 tracings. Twenty tracings were analyzed by ICA algorithm into 20 independent components. Among them, we considered those which changed their rhythm and amplitude to be ictal components and reviewed their topographic maps. Excluding some components with muscle and eye movement artifacts, we reconstructed the components into a conventional EEG format.
RESULTS: Each EEG showed one or more ictal components along with artifact components. Each ictal component in an EEG had a unique field distribution. The field distributions in one patient also varied seizure by seizure. As a group, there was a tendency that the distribution of ictal components of lateral TLE localized to the temporal area and that of OLE to the occipital area, but it was not a consistent finding. After reconstruction, we could get artifact-reduced EEGs.
CONCLUSIONS: ICA can separate ictal components and reduce the artifacts in the ictal EEGs of neocortical epilepsy. The field distribution of the source is different depending on the ictal onset zone and it also changes in each seizure even in the same patient.
Support: This abstract was supported by the Korean Ministry of Health and Welfare (HMP-99-N-02-0003) and Seoul Municipal Boramae Hospital.
Disclosure: Grant - This abstract was supported by the Korean Ministry of Health and Welfare (HMP-99-N-02-0003) and Seoul Municipal Boramae Hospital.