Abstract
The 0–1 test distinguishes between regular and chaotic dynamics for a deterministic system using a time series as a starting point without appealing to any state space reconstruction method. A modification of the 0–1 test allows for the determination of a more comprehensive range of signal dynamic behaviors, particularly in the field of biological signals. We report the results of applying the test and study with more details the PhotoPlethysmoGraphic (PPG) signal behavior from different healthy young subjects, although its use is extensible to other biological signals. While mainly used for heart rate and blood oxygen saturation monitoring, the PPG signal contains extensive physiological dynamics information. We show that the PPG signal, on a healthy young individual, is predominantly quasi-periodic on small timescales (short span of time concerning the dominant frequency). However, on large timescales, PPG signals yield an aperiodic behavior that can be firmly chaotic or a prior transition via an SNA (Strange Nonchaotic Attractor). The results are based on the behavior of well-known time series that are random, chaotic, aperiodic, periodic, and quasi-periodic.
Highlights
IntroductionIn the context of dissipative dynamic systems, recurrence properties and ergodicity facilitate the analysis of physical processes from an only scalar time series, which is nothing other than a sequence of measurements of an observable, regular procedure in practice or of several observables of a physical system, sampled at regular time intervals
A physiological system is limited to the field of dissipative dynamic systems since energy dissipation results are extremely useful to stabilize biological dynamics, ensuring proper functioning under optimal conditions of a living organism [1].In the context of dissipative dynamic systems, recurrence properties and ergodicity facilitate the analysis of physical processes from an only scalar time series, which is nothing other than a sequence of measurements of an observable, regular procedure in practice or of several observables of a physical system, sampled at regular time intervals
Applying the 0–1 test to the reference signals—periodic, quasi-periodic, aperiodic, chaotic, and random signals—and evaluating a modified version of the test, we show how to describe the dynamics of a biological signal: in our case, the PhotoPlethysmoGraphic (PPG) signal
Summary
In the context of dissipative dynamic systems, recurrence properties and ergodicity facilitate the analysis of physical processes from an only scalar time series, which is nothing other than a sequence of measurements of an observable, regular procedure in practice or of several observables of a physical system, sampled at regular time intervals. The PPG signal takes its name from the optical technique, called photoplethysmogram, applied for volumetric analysis of an organ (plethysmogram) or from the device used to measure it, the photoplethysmograph, introduced by A. Hertzman in 1937 [2]. This signal is known as a peripheral pulse wave, mainly employed in clinical settings with the aid of a peripheral pulse monitor or pulse oximeter [3]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
