수면정신생리

수면정신생리 (14권1호 42-48)

Detrended Fluctuation Analysis on Sleep EEG of Healthy Subjects

정상인 수면 뇌파 탈경향변동분석

Shin, Hong-Beom;Jeong, Do-Un;Kim, Eui-Joong;

Department of Psychiatry, Eulji University School of Medicine, and Division of Sleep Study, Department of Neuropsychiatry, Eulji General Hospital;Department of Psychiatry and Behavioral Science, Seoul National University College of Medicine, and Center for Sleep and Chronobiology and Seoul National University Hospital;Department of Psychiatry, Eulji University School of Medicine, and Division of Sleep Study, Department of Neuropsychiatry, Eulji General Hospital;

Abstract

Introduction: Detrended fluctuation analysis (DFA) is used as a way of studying nonlinearity of EEG. In this study, DFA is applied on sleep EEG of normal subjects to look into its nonlinearity in terms of EEG channels and sleep stages. Method: Twelve healthy young subjects (age：$23.8{pm}2.5$ years old, male：female=7：5) have undergone nocturnal polysomnography (nPSG). EEG from nPSG was classified in terms of its channels and sleep stages and was analyzed by DFA. Scaling exponents (SEs) yielded by DFA were compared using linear mixed model analysis. Results: Scaling exponents (SEs) of sleep EEG were distributed around 1 showing long term temporal correlation and self-similarity. SE of C3 channel was bigger than that of O1 channel. As sleep stage progressed from stage 1 to slow wave sleep, SE increased accordingly. SE of stage REM sleep did not show significant difference when compared with that of stage 1 sleep. Conclusion: SEs of Normal sleep EEG showed nonlinear characteristic with scale-free fluctuation, long-range temporal correlation, self-similarity and self-organized criticality. SE from DFA differentiated sleep stages and EEG channels. It can be a useful tool in the research with sleep EEG.

Keywords

Detrended fluctuation analysis;Sleep EEG;Non-linear analysis;