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Estimation of instantaneous complex dynamics through Lyapunov exponents: a study on heartbeat dynamics

Valenza, G and Citi, L and Barbieri, R (2014) 'Estimation of instantaneous complex dynamics through Lyapunov exponents: a study on heartbeat dynamics.' PloS One, 9 (8). creators-Citi=3ALuca=3A=3A. ISSN 1932-6203

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Measures of nonlinearity and complexity, and in particular the study of Lyapunov exponents, have been increasingly used to characterize dynamical properties of a wide range of biological nonlinear systems, including cardiovascular control. In this work, we present a novel methodology able to effectively estimate the Lyapunov spectrum of a series of stochastic events in an instantaneous fashion. The paradigm relies on a novel point-process high-order nonlinear model of the event series dynamics. The long-term information is taken into account by expanding the linear, quadratic, and cubic Wiener-Volterra kernels with the orthonormal Laguerre basis functions. Applications to synthetic data such as the H�non map and R�ssler attractor, as well as two experimental heartbeat interval datasets (i.e., healthy subjects undergoing postural changes and patients with severe cardiac heart failure), focus on estimation and tracking of the Instantaneous Dominant Lyapunov Exponent (IDLE). The novel cardiovascular assessment demonstrates that our method is able to effectively and instantaneously track the nonlinear autonomic control dynamics, allowing for complexity variability estimations.

Item Type: Article
Uncontrolled Keywords: Heart; Humans; Electrocardiography; Sensitivity and Specificity; Stochastic Processes; Reproducibility of Results; Heart Rate; Algorithms; Nonlinear Dynamics; Models, Cardiovascular; Computer Simulation; Heart Failure
Subjects: T Technology > TK Electrical engineering. Electronics Nuclear engineering
Divisions: Faculty of Science and Health
Faculty of Science and Health > Computer Science and Electronic Engineering, School of
SWORD Depositor: Elements
Depositing User: Elements
Date Deposited: 23 Jan 2015 12:35
Last Modified: 23 Sep 2022 18:26

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