Wavelet transform coherence estimates in cardiovascular analysis: Error analysis and feasibility study

Abstract

Wavelet transform coherence (WTC) can provide insight into the transient linear order of the regulatory mechanisms, via the computation of time-frequency maps of the time-variant coherence. This paper presents a framework for applying WTC for quantitative analysis of coherence in cardiovascular variability research.Computer simulations were performed to estimate the accuracy of the WTC estimates and a method for determining the coherence threshold for specific frequency band was developed and evaluated. Finally, we demonstrated, in two representative situations, the dynamic behavior of RSA through the analysis of the WTC between HR and respiration signals. This emphasizes that continuous wavelet transform (CWT) and its application to WTC is a useful tool for dynamic analysis of cardiovascular variability.

Statistical validation of wavelet transform coherence method to assess the transfer of calf muscle activation to blood pressure during quiet standing

“…Previous research with a similar application of WTC methods has shown comparable results with acceptable differences from the current study [19,20,23]. The differences in the values of the statistical measures and behavior with different values of the Morlet coefficient, ω 0 , were as expected based on the different types of signals under investigation.…”

Wavelet coherence reveals entrainment of heart rate variability among people involved in group activities

“…4 we represent the wavelet coherence among the subjects S 1 , S 2 , and S 3 , using the definition in Eq. (12). From this figure, it becomes evident that there is a high degree of entrainment among all the subjects, for activity A1 and A6 with a period of about 12 seconds, and for activity A7 with a period of about 4 seconds.…”

“…C (k,s) x1,...,xN is calculated according to Eq. (12). Given this definition, we can also calculate a new measure, namely the entrainment level, between each 2 The figures in this section are best viewed in color.…”

“…Finally, we present a new measure of the entrainment among a group of practitioners, defining the wavelet coherence among a set of N > 2 signals. To the best of our knowledge, the study of such a coupling has been done only between two physiological parameters [12] but never for signals from two different individuals or, as in our case, for a group of people. We also propose a graphical representation of connections within the group, derived from the coherence signal.…”

Cross-Wavelet Time-Frequency Analysis Reveals Sympathetic Contribution to Baroreflex Sensitivity as Cause of Variable Phase Delay Between Blood Pressure and Heart Rate

“…Although several authors have used wavelet techniques in the study of cardiovascular regulation (e.g., Brychta et al, 2006; Stankovski et al, 2013; Singh et al, 2018), only few papers are known to us which applied cross wavelet techniques for the analysis of blood-pressure and heart-rate variability (Keissar et al, 2006, 2008, 2010; Kashihara et al, 2009). The first papers of Keissar et al (2006, 2008) show principally the usefulness of this technique in the study of the ANS. In their 2010 paper these authors present the fluctuations of computed BRS values for supine subjects and during active standing up.…”