Phase synchrony and coherence analysis of bio-signals using cross-time-frequency distributions

Phase synchrony and coherence analysis of bio-signals such as EEG, HRV, Respiratory and Blood Pressure can be explored to study the phase coupling between different physiological activities for different biological mechanisms. Due to the non-stationary nature of these bio-signals, the preferred approach requires a cross time-frequency based representation to describe the phase coupling between two or more different spatially recorded entities. The selected technique for this purpose is the cross-Modified S transform (X-MST), due to some properties of the modified S transform (MST), such as phase preservation. Both simulated examples and real data demonstrate the usefulness of the technique. The performance and limitations of the X-MST method are discussed in the context of a comparison with a quadratic Time-Frequency distributions such as the cross-Wigner-Ville distribution (WVD).