• 융합신호처리학회논문지
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• 제21권1호
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• pp.7-12
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• 2020

수술 중 마취 깊이를 측정하는 방법으로 뇌파를 이용한 다양한 파라미터들이 사용되고 있으며, 실제 임상에서는 선형분석 기법 중 하나인 SEF가 널리 사용되고 있다. 그러나 최근 EEG를 포함한 생체학적 신호는 비선형 성질을 가지고 있다는 연구결과가 발표되면서, 이를 기반으로 한 파라미터 개발이 이뤄지고 있다. 본 연구에서는 보다 정확한 EEG 측정과 분석을 위해 비선형 분석 기법 기반의 파라미터를 개발과 이에 대한 정현파 분석을 통한 데이터와의 비교 분석을 통해 수술 중 전자장비와 EEG 계측 시 혼입될 수 있는 노이즈를 추출하고자 한다.

• 대한한의진단학회지
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• 제11권2호
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• pp.68-83
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• 2007

Background and Purpose: According to chaos theory, irregular signals of electroencephalogram can interpretated by nonlinear method. Chaotic nonlinear dynamics in EEG can be studied by calculating the correlation dimension. The aim of this study is to analyze EEG by correlation dimension and do Correlation Analysis of correlation dimension and K-POMS factors score. Method: EEG raw data were measured during 15 minutes and choosed 40 seconds. We calculated correlation dimension and used surrogate data method for checking nonlinear data. After then do correlation analysis. Result and Conclusion: Correlation dimension of channel 6, channel 7 and channel 8 are showed significant correlation with vigor factor.

• 대한한의진단학회지
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• 제11권2호
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• pp.116-127
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• 2007

Background and Purpose: Acording to chaos theory, irregular signals of electroencephalogram can interpretated by nonlinear method. Chaotic nonlinear dynamics in EEG can be studied by calculating the correlation dimension. The aim of this study is to analyze EEG by correlation dimension and do Correlation Analysis of correlation dimension and cold-heat score Method: EEG raw data were measured during 15 minutes and choosed 40 seconds. We calculated correlation dimension and used surrogate data method for checking nonlinear data. After then do correlation analysis Result and Conclusion: Correlation dimension of channel 7 and channel 8 are showed significant correlation with cold score.

• 대한한의진단학회지
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• 제11권2호
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• pp.128-140
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• 2007

Purpose: We performed this study to examine the correlationship between EEG complexity and impedance cardiography data using correlation analysis. Method: This study performed on 30 healthy subjects(16 males, 14 females). Before and after natural respiration, ICG data were recorded, and EEG raw data were measured by moving windows during 15 minutes. The correlation dimension(D2) was calculated from 15 minutes data. 8 channels EEG data were analysed with 9 index of ICG data by correlation analysis. Result: 1. ACI of impedance cardiography had significant correlationship with ch.4 of EEG complexity(p=0.03). 2. VI of impedance cardiography had significant correlationship with ch.3 of EEG complexity(p=0.034) and ch.4 of EEG complexity(p=0.017). 3. HR, TFC, PEP, LVET, STR of impedance cardiography had no significant correlationship with all of 8 channel EEG complexity. Conclusions: These results suggest that nonlinear analysis of EEG and impedance cardiography have some significant correlationship. And it can make out relationship between brain system and cardiovascular system. In the future, therefore, more study of these fields are necessary.

• 산업경영시스템학회지
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• 제18권36호
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• pp.61-69
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• 1995

The diagnosis has an very important role in curing dementia. But there was not the effective method to diagnose it until now. In this paper we analyzed the EEG in Alzheimer's disease and normal control groups to differentiated them by nonlinear parameter such as the correlation dimension. And we propose the nonlinear analysis of EEG in Alzheimer's disease as a useful tool of early diagnosis of it.

• Annals of Clinical Neurophysiology
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• 제4권1호
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• pp.28-33
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• 2002

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.

• 대한한의진단학회지
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• 제11권2호
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• pp.96-115
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• 2007

Background and Purpose: Electroencephalogram(EEG) is a multi-scaled signal consisting of several components of time series with different origins. Recently, because of the absence of an identified metric which quantifies the complex amount of information, there are many limitations in using such a linear method. According to chaos theory, irregular signals of EEG can also result from low dimensional deterministic chaos. Chaotic nonlinear dynamics in the EEG can be studied by calculating the correlation dimension. The aim of this study is to analyze correlation between the correlation dimension of EEG and psychological Test (TCI). Methods: Before and after moxibustion treatment, EEG raw data were measured by moving windows during 15 minutes. The correlation dimension(D2) was calculated from stabilized 40 seconds in 15 minutes data. 8 channels EEG study on the Fp, F, T, P was carried out in 30 subjects. Results: Correlation analysis of TCI test is calculated with deterministic non-linear data and stochastic non-linear data. 1. Novelty seeking in temperament is positive correlated with D2 of EEG on Fp. 2. reward dependence in temperament is positive correlated with D2 of EEG on T3,T4 and negative correlated with D2 of EEG on P3,P4. 3. self directedness in character is positive correlated with D2 of EEG on F4, P3. 4. Harm avoidance is negative correlated with D2 of EEG on Fp2, T3, P3. Conclusion: These results suggest that nonlinear analysis of EEG can quantify dynamic state of brain abolut psychological Test (TCI).

• 대한한의진단학회지
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• 제11권2호
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• pp.84-95
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• 2007

Background and Purpose: We have studied the trends of EEG signals in the voluntary breathing condition by applying the fractal analysis. According to chaos theory, irregularity of EEG signals can result from low dimensional deterministic chaos. A principal parameter to quantify the degree of Chaotic nonlinear dynamics is correlation dimension. The aim of this study was to analyze correlation between the correlation dimension of EEG and HRV(heart rate variability). We have studied the trends of EEG signals in the voluntary breathing condition by applying the fractal analysis. Methods: EEG raw data were measured by moving windows during 15 minutes. Then, the correlation dimension(D2) was calculated by each 40-seconds-segment in 15 minutes data, totally 36 segments. 8 channels EEG study on the Fp, F, T, P was carried out in 30 subjects. Results and Conclusion: Correlation analysis of HRV was calculated with deterministic non-linear data and stochastic non-linear data. 1. Ch1(Fp1), Ch4(F3), Ch4(F4) is positive correlated with In LF. 2. Ch1(Fp1), Ch3(F3) is positive correlated with In TF.

• Annals of Clinical Neurophysiology
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• 제4권1호
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• pp.21-27
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• 2002

Background : Spatial analysis of EEG is a phenomenal assessment and not so informative for phase space and dynamic aspect of EEG data. In contrast, nonlinear EEG analysis attempts to characterize the dynamics of neural networks in the brain. We have analyzed the features of EEG nonlinearly in subjects with white matter change on brain MRI and compared the results with cognitive function in each. Methods : Digital EEG data were taken for 30 seconds in 9 subjects with white matter degeneration and in 5 healthy normal controls without white matter change on MRI. Then we analyzed them nonlinearly to calculate the correlation dimension(D2) using the MATLAB software. The cognitive function was assessed by 3MS(modified mini-mental state examination). The severity of white matter change was assessed by Scheltens scale. Results : The mean D2 value of normal control was greater than that of white matter degeneration group. The D2s of some channels were correlative with 3MS and degree of white matter degeneration significantly. Conclusions : nonlinear analysis of EEG can be used as one of adjuvant functional studies for prediction of cognitive impairment in subjects with white matter degeneration and subcortical white matter change can be influential on cognitive function and correlation dimension of EEG.

• 한국지능시스템학회논문지
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• 제12권5호
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• pp.442-450
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• 2002

뇌 기능의 연구수단으로써 널리 사용되고 있는 뇌파(Electroencephalogram, EEG)는 측정시에 노이즈(noise)나 잡파(artifact)가 섞여서 측정되기 쉽다. 본 연구에서는 뇌파에 포함된 잡파들을 분리하기 위해서 독립성분분석(ICA)을 뇌파신호에 적용하였다. 먼저 정상인의 안구운동(Eye Movement)과 관련된 잡파가 나타나는 뇌파 신호에 대해서 독립성분분석을 적용하여 소스로 추정되는 각각의 독립성분들을 분리해 내었다 분리된 신호에 대하여 잡파로 보이는 신호를 제거하고 재구성된 뇌파 신호와 잡파가 제거되기 전인 원래의 신호에 대하여 각각 상관차원(correlation dimension) 및 리아프노프 지수(Iyapunov exponent)등과 같은 비선형 분석법을 적용하여 두 신호의 유의한 차이점을 밝히고, 분리된 독립 신호들의 해부학적 발생위치 및 분포를 추정하였다. 시각적으로 복잡한 뇌파신호에 대하여 독립성분분석을 통하여 뇌 활동의 시각적, 공간적 분석이 가능함을 나타내었을 뿐만 아니라 비선형 분석을 통한 뇌파 신호의 정량적 분석을 통하여 시각적으로 복잡한 뇌파의 유의미한 변화를 관찰할 수 있었다.