Modified Fourier-Domain Transfer Entropy for Cardiovascular Analysis: Insights Into Aging Mechanisms.

Area of Science:

• Cardiovascular System Dynamics
• Biomedical Signal Processing
• Nonlinear Dynamics

Background:

• Causality between heart period (HP) and systolic arterial pressure (SAP) is crucial for understanding cardiovascular regulation.
• Traditional methods may lack sensitivity in detecting subtle causal interactions across multiple scales.

Purpose of the Study:

• Introduce Modified Multiscale Fourier-domain Transfer Entropy (MMFTE) for analyzing causality in cardiovascular dynamics.
• Evaluate MMFTE's sensitivity, robustness, and effectiveness compared to existing methods.
• Investigate age-related differences in HP-SAP coupling using MMFTE.

Main Methods:

• Developed Modified Multiscale Fourier-domain Transfer Entropy (MMFTE) as an extension of Fourier-domain Transfer Entropy (FTE).
• Validated MMFTE using simulations, assessing sensitivity to weak coupling and robustness to data length.
• Applied MMFTE to analyze cardiovascular data from young and elderly subjects, examining HP-SAP coupling across multiple scales.

Main Results:

• MMFTE demonstrated higher sensitivity and robustness than FTE in simulations.
• Analysis revealed significantly reduced HP-SAP coupling in elderly subjects across multiple frequency and time scales.
• MMFTE yielded lower p-values and identified differences across a broader range of scales compared to FTE.

Conclusions:

• MMFTE is a sensitive and robust method for quantifying causality in cardiovascular interactions across multiple scales.
• Age-related differences in HP-SAP coupling are effectively characterized by MMFTE.
• The method offers a new perspective for exploring complex cardiovascular dynamics.