Beyond Fractals and 1/f Noise: Multifractal Analysis of Complex Physiological Time Series Conference Paper uri icon

abstract

  • We investigate time series with 1/f-like spectra generated by two physiologic control systems- --the human heartbeat and human gait. We show that physiological fluctuations exhibit unexpected``hidden''structures often described by scaling laws. In particular, our studies indicate that when analyzed on different time scales the heartbeat fluctuations exhibit cascades of branching patterns with self-similar (fractal) properties, characterized by long- range power-law anticorrelations. We find that these scaling features change during sleep and wake phases, and with pathological perturbations. Further, by means of a new wavelet- based technique, we find evidence of multifractality in the healthy human heartbeat even under resting conditions, and show that the multifractal character and nonlinear properties of the healthy heart are encoded in the Fourier phases. We uncover a loss of multifractality …

publication date

  • January 1, 2001