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Multifractal mass exponent spectrum of complex physiological time series

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Chinese Science Bulletin 2010年第19期55卷 1996-2003页

作者： YANG XiaoDong HE AiJun ZHOU Yong ning xinbao School of Computer Science and Technology China University of Mining and Technology Xuzhou 221116 China Department of Electronic Science and Engineering Institute for Biomedical Electronic Engineering Nanjing University Nanjing 210093 China

Physiological signal belongs to the kind of nonstationary and time-variant ***,the nonlinear analysis methods may be better to disclose its characteristics and *** have been plenty of evidences that physiological signal generated by complex self-regulated system may have a fractal *** this work,we introduce a new measure to characterize multifractality,the mass exponent spectrum curvature,which can disclose the complexity of fractal structure from total bending degree of the *** parameter represents the nonlinear superpositions of the discrepancies of fractal dimension from all adjacent points in the curve and therefore solves the problem of original parameters for not fully reflecting the information of entire subsets in the fractal *** evaluations of deterministic fractal system Cantor measure validate that it is completely effective in exploring the complexity of chaotic series,and is also not affected by nonstability of the signal as well as disturbances of the *** then apply it to the analysis of human heart rate variability(HRV) signals and sleep electroencephalogram(EEG) *** experimental results show that this method can be better to discriminate cohorts under different physiological and pathological *** with the indicator of singularity spectrum width,there are some improvements both on the computing efficiency and *** conclusion may provide some valuable information for clinical diagnoses.

关键词：生理信号多重分形指数谱时间序列质量非线性分析方法序列复杂性分形结构

RESEARCH PROGRESS IN NONLINEAR ANALYSIS OF HEART ELECTRIC ACTIVITIES

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Chinese Science Bulletin 2006年第4期51卷 385-393页

作者： ning xinbao BIAN Chunhua WANG Jun CHEN Ying State Key Laboratory of Modem Acoustics Institute for BiomedicalElectronic Engineering Department of Electronic Science & Engineering Nanjing University Nanjing 210093 China

Nonlinear science research is a hot point in the world. It has deepened our cognition of determinism and randomicity, simplicity and com-plexity, noise and order and it will profoundly influ-ence the progress of the study of natural science, including life science. Life is the most complex nonlinear system and heart is the core of lifecycle system. In the late more than 20 years, nonlinear research on heart electric activities has made much headway. The commonly used parameters are based on chaos and fractal theory, such as correlation dimension, Lyapunov ex-ponent, Kolmogorov entropy and multifractal singu-larity spectrum. This paper summarizes the commonly used methods in the nonlinear study of heart electric signal. Then, considering the shortages of the above tradi-tional nonlinear parameters, we mainly introduce the results on short-term heart rate variability (HRV) signal (500 R-R intervals) and HFECG signal (1-2s). Finally, we point out it is worthwhile to put emphasis on the study of the sensitive nonlinearity parameters of short-term heart electric signal and their dynamic character and clinical effectivity.

关键词：心电图心率非线性分析混沌信号研究进展

Distribution of correlation dimensions of synchronous 12-lead ECG signals

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Chinese Science Bulletin 2000年第17期45卷 1628-1632页

作者： WANG Zhenzhou ning xinbao ZHANG Yu DU Gonghuan State Key Laboratory of Modern Acoustics and Department of Electronic Science and Engineering Nanjing UniversityNanjing 210093China

Correlation dimensions D2 of the synchronous 12-lead ECG signals have been investigated for the first time by distributed multi-sensor (multi-electrode) technique. The results show that correlation dimension of heart has the distributed characteristics. D2 calculated from different lead ECG signals is not a constant regardless of a healthy person or a coronary heart disease (CHD) patient with sinus rhythm. But with the same lead signal, D2 of CHD patients is evidently smaller than that of a healthy person except I, II, III leads. A healthy person and CHD patient can be identified by D2 statistically and D2 shows the potential application in the diagnosis of the CHD patients.

关键词： correlation dimension distributed multi-sensor electrocardiogram (ECG) coronary heart disease (CHD).

Complexity and characteristic frequency studies in ECG signals of mice based on multiple scale factors

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Science China(Life Sciences) 2011年第6期54卷 544-552页

作者： YANG XiaoDong HE AiJun LIU Peng SUN TongFeng ning xinbao School of Computer Science and Technology China University of Mining and TechnologyXuzhou 221116China School of Electronic Science and Engineering Institute for Biomedical Electronic EngineeringNanjing UniversityNanjing 210093China

Existing methods of physiological signal analysis based on nonlinear dynamic theories only examine the complexity difference of the signals under a single sampling *** developed a technique to measure the multifractal characteristic parameter intimately associated with physiological activities through a frequency scale *** parameter is highly sensitive to physiological and pathological *** received various drugs to imitate different physiological and pathological conditions,and the distributions of mass exponent spectrum curvature with scale factors from the electrocardiogram (ECG) signals of healthy and drug injected mice were ***,we determined the characteristic frequency scope in which the signal was of the highest complexity and most sensitive to impaired cardiac function,and examined the relationships between heart rate,heartbeat dynamic complexity,and sensitive frequency scope of the ECG *** found that all animals exhibited a scale factor range in which the absolute magnitudes of ECG mass exponent spectrum curvature achieve the maximum,and this range (or frequency scope) is not changed with calculated data points or maximal coarse-grained scale ***,the heart rate of mice was not necessarily associated with the nonlinear complexity of cardiac dynamics,but closely related to the most sensitive ECG frequency scope determined by characterization of this complex dynamic features for certain heartbeat ***,we found that the health status of the hearts of mice was directly related to the heartbeat dynamic complexity,both of which were positively correlated within the scale factor around the extremum region of the multifractal *** increasing heart rate,the sensitive frequency scope increased to a relatively high *** conclusion,these data provide important theoretical and practical data for the early diagnosis of cardiac disorders.

关键词：信号分析特征频率心电图复杂性小鼠多尺度频率范围生理活动

Lyapunov exponents for synchronous 12-lead ECG signals

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Chinese Science Bulletin 2002年第21期47卷 1845-1848页

作者： WANG Zhenzhou LI Zheng WEI Yixiang ning xinbao LIN Yuzheng Department of Engineering Physics Tsinghua UniversityBeijing100084China Department of Electronic Science and Engineering Nanjing UniversityNanjing 210093China

The Lyapunov exponents of synchronous 12-lead ECG signals have been investigated for the first time using a multi-sensor (electrode) technique. The results show that the Lyapunov exponents computed from different locations on the body surface are not the same, but have a distribution characteristic for the ECG signals recorded from coronary artery disease (CAD) patients with sinus rhythms and for signals from healthy older people. The maximum Lyapunov exponent L1 of all signals is positive. While all the others are negative, so the ECG signal has chaotic characteristics. With the same leads, L1 of CAD patients is less than that of healthy people, so the CAD patients and healthy people can be classified by L1, L1 therefore has potential values in the diagnosis of heart disease.

关键词： CAD multi-sensor synchronous 12-lead ECG Lyapunov exponents chaos.

Multifractal analysis of resting state fMRI series in default mode network: age and gender effects

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Chinese Science Bulletin 2014年第25期59卷 3107-3113页

作者： Huangjing Ni Xiaolin Huang xinbao ning Chengyu Huo Tiebing Liu De Ben School of Electronic Science and Engineering Nanjing University School of Physics and Electronic Engineering Changshu Institute of Technology Department of Biomedical Engineering Jinling Hospital

Age-related changes of resting state in default mode network(DMN)may provide new clues to the developing mechanism of normal brain as well as early diagnosis and therapy of some neuropsychiatric *** application of multifractal theory to functional magnetic resonance imaging(fMRI)signals has recently raised increasing *** aim to explore the multifractal characteristics underlying the resting state functional magnetic resonance imaging(rs-fMRI)series extracted from DMN,and two issues are mainly discussed:(1)whether there exist multifractals in rs-fMRI series;(2)whether it is possible to distinguish between the different ages or genders by means of multifractal *** demonstrated the existence of multifractals in rs-fMRI series in *** addition,slight differences between young subjects and middle-aged or elderly subjects can be successfully detected by Dasa,a modified measure we ***,it is revealed that the rs-fMRI series from young subjects possess smaller averaged scale index and weaker long range correlation,while those from middle-aged or elderly people present increasing averaged scale index andstronger long range *** no significant statistical differences has been found between male and female *** results,therefore,highlight the potential usefulness of multifractal analysis in fMRI series of a certain brain region,and provide important insights into healthy aging in DMN.

关键词：多重分形分析功能磁共振成像年龄相关状态静息性别网络磁共振成像技术

Sign series entropy analysis of short-term heart rate variability

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Chinese Science Bulletin 2009年第24期54卷 4610-4615页

作者： BIAN ChunHua MA QianLi SI JunFeng WU XuHui SHAO Jun ning xinbao WANG DongJin Key Laboratory of Modern Acoustics Institute for Biomedical Electronic Engineering Department of Electronic Science and Engi- neering Nanjing University Nanjing 210093 China College of Geography and Biological Information Nanjing University of Posts and Telecommunications Nanjing 210003 China The Affiliated Drumtower Hospital of Nanjing University Medical School Nanjing 210008 China

Complexity and nonlinearity approaches can be used to study the temporal and structural order in heart rate variability (HRV) signal, which is helpful for understanding the underlying rule and physiological essence of cardiovascular regulation. For clinical applications, methods suitable for short-term HRV analysis are more valuable. In this paper, sign series entropy analysis (SSEA) is proposed to characterize the feature of direction variation of HRV. The results show that SSEA method can detect sensitively physiological and pathological changes from short-term HRV signals, and the method also shows its robustness to nonstationarity and noise. Thus, it is suggested as an efficient way for the analysis of clinical HRV and other complex physiological signals.

关键词：心率变异性变异性分析熵分析短期临床应用抗原检测非线性方法心血管调节

Nonlinear short-term heart rate variability prediction of spontaneous ventricular tachyarrhythmia

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Chinese Science Bulletin 2008年第16期53卷 2446-2453页

作者： ZHUANG JianJun ning xinbao DU SiDan WANG ZhenZhou HUO ChengYu YANG Xi FAN AiHua Key Laboratory of Modern Acoustics and Department of Electronic Science & Engineering Institute for Biomedical ElectronicEngineering Nanjing University Nanjing 210093 China Department of Medical Engineering Kunming People's Liberation Army General Hospital Kunming 650032 China

As malign ventricular tachyarrhythmias triggering sudden cardiac death (SCD), both ventricular tachycardia (VT) and ventricular fibrillation (VF) are major causes of mortality. The most efficient ther- apy for SCD prevention is implantable cardioverter defibrillators (ICD). The ICD can accurately and ef- fectively identify the forthcoming of fatal ventricular tachyarrhythmias and deliver a shock in order to restore patients’ normal sinus rhythm. In this study, two nonlinear complexity measures based on en- tropy: approximate entropy (ApEn) and sample entropy (SampEn) as well as two time linear indices: the mean RR interval (the average of time intervals between consecutive R-waves) and the standard devia- tion of RR intervals were used for short-term forecasting of VT-VF occurrence. The last small sections of interbeat intervals preceding 135 VT-VF episodes from 78 patients stored by the ICD were analyzed and compared with individually acquired control time series (CON series) from the same patients, which are normally intrinsic sinus rhythms. The results demonstrate that in addition to an obvious in- crease in heart rates of the patients, the values of two entropy measures are significantly smaller for VT-VF episodes than those for CON series. Conclusions can be drawn that when a ventricular tach- yarrhythmia approaches, the sympathetic tone of the patients is increased, and the complexity of their RR intervals immediately before the onset of VT-VF events is obviously lower than that of RR intervals recorded during sinus rhythms. For a better separation, the optimal range of threshold r is determined for two algorithms. ApEn and SampEn measures might be the suitable nonlinear parameters for short- term prediction of life-threatening ventricular tachyarrhythmias in the application of the cardioversion and defibrillation.

关键词：心室非线性短期心率变异性预测

The SARD variety of multi-fractality of ventricular epicardial mapping during ischemia

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Chinese Science Bulletin 2006年第7期51卷 809-814页

作者： CHEN Ying Martyn P. Nash ning xinbao WANG Yelin David J. Paterson WANG Jun State Key Laboratory of Modern Acoustics Institute for Biomedical Electronical Engineering Nanjing University Nanjing 210093 China Engineering Science and Bioengineering Institute University of Auckland Private Bag 92019 NZ Laboratory of Physiology University of Oxford Parks Road Oxford OX13PT UK

We have analyzed cardiac ische- mia-reperfusion in an animal model using epicardial electropotential mapping. We investigated the rela- tionship between ischemia and variability of multi- fractality in epicardial electrograms. We present a new parameter called the singularity spectrum area reference dispersion (SARD) that clearly demon- strates the change in multifractility with the extent of myocardiaischemia. By contrasting the 3D ventricular epicardial SARD map with the activation map, we conclude that myocardial ischemia significantly in- fluences the variety of multifractality of ventricular epicardium electrograms and the SARD parameter is useful in correlating multifractality of epicardial elec- trograms with location of ischemia closely.

关键词：局部缺血 SARD 非线性基因定位室性心外膜