Velocity and Directionality of the Electrohysterographic Signal Propagation

Abstract

ObjectiveThe initiation of treatment for women with threatening preterm labor requires effective distinction between true and false labor. The electrohysterogram (EHG) has shown great promise in estimating and classifying uterine activity. However, key issues remain unresolved and no clinically usable method has yet been presented using EHG. Recent studies have focused on the propagation velocity of the EHG signals as a potential discriminator between true and false labor. These studies have estimated the propagation velocity of individual spikes of the EHG signals. We therefore focus on estimating the propagation velocity of the entire EHG burst recorded during a contraction in two dimensions.Study DesignEHG measurements were performed on six women in active labor at term, and a total of 35 contractions were used for the estimation of propagation velocity. The measurements were performed using a 16-channel two-dimensional electrode grid. The estimates were calculated with a maximum-likelihood approach.ResultsThe estimated average propagation velocity was 2.18 (±0.68) cm/s. No single preferred direction of propagation was found.ConclusionThe propagation velocities estimated in this study are similar to those reported in other studies but with a smaller intra- and inter-patient variation. Thus a potential tool has been established for further studies on true and false labor contractions.

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

“…Studies on the propagation of the uterine electrical busts on women in labour reveal, similar to the propagation of the pressure wave (Caldeyro-Barcia & Alvarez 1952), a predominantly downward propagation and a preferred origin of the burst in the upper/ovarian region of the uterus in women as well as in the guinea-pig (Planes et al 1984, Norwitz et al 1999, Lammers et al 2008, Mikkelsen et al 2013. However, in women, upward and multidirectional propagation patterns, including simultaneous upward and downward propagation, have also been frequently reported while analysing the myometrial electrical burst , Mikkelsen et al 2013, Lange et al 2014. Analysis of the centre of uterine activity, obtained by a Gaussian fitting of the spatial distribution of the burst energy along a two-dimensional grid of electrodes, revealed that women who delivered successfully vaginally, in contrast to those who had arrested labour, had a predominant upward direction of the uterine activity centre (Buhimschi 2009, Euliano et al 2009).…”

“…, Lange et al . ). Analysis of the centre of uterine activity, obtained by a Gaussian fitting of the spatial distribution of the burst energy along a two‐dimensional grid of electrodes, revealed that women who delivered successfully vaginally, in contrast to those who had arrested labour, had a predominant upward direction of the uterine activity centre (Buhimschi , Euliano et al .…”

“…Values of speed with the same average and similar variability, equal to 0.68 cm s −1 , have been found using a two‐dimensional 16‐channel grid in six women in active labour at term (Lange et al . ). On a comparable number of subjects in labour, eight channel recordings also lead to estimated values of burst propagation speed in the 4–5 cm s −1 range (Rabotti et al .…”

Advanced artificial neural network classification for detecting preterm births using EHG records

“…However, only one dimension of propagation is considered at a time, which is based on the estimation of time delays between spikes. In comparison, Lange et al (Lange et al, 2014) estimate the PV of the entire EHG burst that occurs during a contraction. This has been achieved by calculating the bursts corresponding to a full contraction event.…”

Evaluation of Advanced Artificial Neural Network Classification and Feature Extraction Techniques for Detecting Preterm Births Using EHG Records

“…However, only one dimension of propagation is considered at a time, which is based on the estimation of time delays between spikes. In comparison, Lange et al (Lange et al, 2014) estimate the PV of the entire EHG bursts that occur during a contraction by calculating the bursts corresponding to a full contraction event. The results illustrate that the estimated average propagation velocity is 2.18 (60.68) cm/s.…”