On the propagation analysis of electrohysterographic signals

Abstract

Abstract-Premature birth is a leading cause of fetal mortality and long-term morbidity. The effective treatment of preterm uterine contractions requires new methods for predicting delivery. The electrohysterographic (EHG) signal is a measure of the bioelectrical process underlying the uterine contraction. The analysis of parameters derived from the EHG signal can therefore provide fundamental information for the prognosis of labor. In this paper, we focus on the propagation of the EHG signal recorded during delivery by multiple electrodes. For the inter-electrode delay assessment and propagation analysis, two different methods are implemented. One is based on the prior estimation of the uterine mechanical activity by EHG signal processing. The delay is then calculated by the cross-correlation function between the mechanical activity estimated at each sensor. The other method is a high temporal resolution adaptive delay estimator that operates directly on EHG signals. The previously demonstrated accuracy of the mechanical estimates and the agreement between the delays provided by the methods confirm the tight relationship between the mechanical and electrical activity of the uterus. However, our results suggest that a higher temporal resolution delay estimator is preferred.

Propagation of electrical activity in uterine muscle during pregnancy: a review

“…In fact, although bipolar measurements provide a better signal‐to noise ratio, due to the a priori unknown pacemaker region and direction of propagation, unipolar recordings should be preferred for the analysis of electrical propagation in the uterus (Rabotti et al . , , Hassan et al . ).…”

“…In the vast majority of reviewed studies which reported conduction speed measurements unipolar derivations were used. In fact, although bipolar measurements provide a better signal-to noise ratio, due to the a priori unknown pacemaker region and direction of propagation, unipolar recordings should be preferred for the analysis of electrical propagation in the uterus (Rabotti et al 2007, 2008a, Hassan et al 2011. Being the myometrium a smooth muscle, values of propagation speed in the order of few centimetres per second could be expected (Devedeux et al 1993).…”

“…High-density measurements for the non-invasive estimation of uterine spike propagation velocity during labour contractions were first described on pregnant women using a two-dimensional flexible grid comprising 64 channels (Rabotti et al 2010b, Rabotti et al 2010, Rabotti et al 2008, de Lau et al 2013). An example of the recording is reported in Fig.…”

Assessing Velocity and Directionality of Uterine Electrical Activity for Preterm Birth Prediction Using EHG Surface Records

“…In addition to the temporal, spectral, and non-linear parameters already discussed, the EHG electrical activity, as measured on the abdominal wall, also allows propagation analysis of EHG signals [ 32 ], propagation analysis of uterine contractions [ 33 ], and evaluation of directionality and synchronization of the EHG signals [ 34 ]. These include: estimation of conduction or propagation velocity amplitudes [ 10 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 ], estimation of conduction velocity directions [ 39 , 40 , 41 , 42 , 43 ], estimation of propagation patterns [ 40 , 42 ], estimation of directionality, synchronization, and coupling [ 34 , 44 ], and estimation of spatiotemporal EHG patterns [ 45 ].…”

Electrohysterography of labor contractions: propagation velocity and direction

“…In addition, current literature does not support a downward propagation of contractions. Uterine electromyographic studies, often designated as electrohysterography (EHG), have been conducted since 1931 , but a convincing overall preferred propagation direction has not been demonstrated . Only a few early studies suggest the existence of a preferred propagation direction .…”