Physiological Signal Variability Analysis Based on the Largest Lyapunov Exponent

Globally, cardiovascular disease is the world´s leading killer and is projected to remain so. The physiological signal variabilities, such as heart rate variability and pulse transit time variability, are useful indices to assess cardiovascular system function. The largest Lyapunov Exponent is used in this paper to analyze the physiological signal variability in cardiovascular system. Eight healthy volunteers participated in the test. Results showed that the method used in this paper is stable, robust to the embedding dimension and mean period, and reliable for small data sets. Thus, the largest Lyapunov exponent calculated by the small data sets method is suitable for physiological signal variability analysis.