Analysis of Foetal Heart Rate Variability Components by Means of Empirical Mode Decomposition

Foetal heart rate variability (FHRV) is important in foetal wellbeing assessment. However, a gold standard for its evaluation is not yet available. Here, a rather new methodology, the empirical mode decomposition (EMD), is proposed to decompose FHR signal in its components. To test the reliability of this methodology, we employed simulated FHR signals, "clean" and noisy, with characteristics defined a priori and computed two indices of foetal health, the sympatho-vagal balance (SVB) and the standard deviation of FHR signal (ASD). Results obtained in comparison between values set for the simulation and those estimated after EMD demonstrated that EMD could be useful for evaluation of FHRV components directly in time domain. The error in the indices estimation was on average just over 1% for SVB and zero for ASD. In presence of noise, the error in ASD estimation was below 8% whereas that in SVB evaluation increases becoming almost 30%.