Annals of Clinical Neurophysiology

The Korean Society of Clinical Neurophysiology (대한임상신경생리학회)
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Nonlinear Characterization of EEG Under the Internal and External Stimuli

내·외적인 자극을 받는 뇌파의 비선형 동력학적 특징

  • Jung, Ki-Young (Department of Neurology, Chungnam National University Hospital, Institute for Brain Research, Chungnam National University) ;
  • Kim, Jae-Moon (Department of Neurology, Chungnam National University Hospital, Institute for Brain Research, Chungnam National University) ;
  • Yoo, Cheol-Seung (Inje University, Chaos and Nonlinear Biological Laboratory) ;
  • Yi, Sang-Hoon (Inje University, Chaos and Nonlinear Biological Laboratory)
  • 정기영 (충남대학교 의과대학 신경과학교실, 충남대학교 뇌과학연구소) ;
  • 김재문 (충남대학교 의과대학 신경과학교실, 충남대학교 뇌과학연구소) ;
  • 유철승 (인제대학교, 카오스 및 비선형 생체동력학 연구실) ;
  • 이상훈 (인제대학교, 카오스 및 비선형 생체동력학 연구실)
  • Published : 2002.05.01
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Abstract

Backgrounds and objective : EEG reflect dynamic changes of continuous neuronal activities by internal and external stimuli. The aim of this study is to quantify nonlinearly the local dynamic differences among EEG data corresponding to different states of brain. Methods : EEG was recorded from twelve healthy normal subjects(mean age, 29.7 years; 8 men and 4 women) using digital EEG machine. 18-channel EEG data were selected during eyes closed(EC), eyes open(EO), and mental arithmetic(MA) in each subject. Correlation dimension(D2) and largest Lyapunov exponent(LLE) were calculated from three states and average value was mapped 2 dimensionally and compared with each other. Results : The distribution of D2 was relatively symmetric and its value was higher in frontal than in parieto-occipital region during EC. These findings were reversed during EO. Bilateral centro-temporo-parietal region showed high D2 value in MA compared with those in EC, which was more prominent in left side. LLE was larger than zero in all state and showed significant differences among EC, EO and MA(p=0.000). Conclusion : These results suggest that nonlinear analysis of EEG can quantify dynamic state of brain.

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