Title :
Estimation of nonlinear couplings on the basis of complexity and predictability-a new method applied to cardiorespiratory coordination
Author :
Hoyer, Dirk ; Bauer, Reinhard ; Walter, Bernd ; Zwiener, Ulrich
Author_Institution :
Inst. fur Pathophysiol., Friedrich-Schiller-Univ., Jena, Germany
fDate :
5/1/1998 12:00:00 AM
Abstract :
Nonlinear coordination is an essential property of the complex functioning of the autonomic nervous system. Therefore, the coupled behavior of heart rate fluctuations (HRF) and respiratory movements (RM) was analyzed on the basis of their joint reconstruction in phase space. Independence measures of complexity and predictability were approximated from the correlation integrals which enabled the strength of cardiorespiratory couplings to be quantified. These measures were validated in a simulation study of two coupled nonlinear oscillators in dependence on their coupling strength and respective synchronization effects. The cardiorespiratory coordination during quiet sleep and active sleep of newborn piglets was quantified by means of the proposed independence measures of complexity and predictability. The difference of those measures between the sleep states investigated was more significant than the difference of the respective linear coherence peaks.
Keywords :
biomechanics; cardiology; neurophysiology; physiological models; active sleep; autonomic nervous system; cardiorespiratory coordination; complex functioning; correlation integrals; coupled nonlinear oscillators; coupling strength; heart rate fluctuations; linear coherence peaks; newborn piglets; nonlinear couplings estimation; phase space; predictability; quiet sleep; respiratory movements; synchronization effects; Autonomic nervous system; Cardiology; Fluctuations; Heart rate; Medical diagnosis; Mutual coupling; Oscillators; Pediatrics; Sleep; Testing; Animals; Animals, Newborn; Electrocardiography; Electroencephalography; Female; Heart Rate; Male; Models, Biological; Nonlinear Dynamics; Reference Values; Respiratory Mechanics; Sleep; Swine;
Journal_Title :
Biomedical Engineering, IEEE Transactions on