Noninvasive Estimation of the Electrohysterographic Action-Potential Conduction Velocity

Abstract

Abstract-Electrophysiological monitoring of the fetal-heart and the uterine-muscle activity, referred to as an electrohysterogram, is essential to permit timely treatment during pregnancy. While remarkable progress is reported for fetal-cardiac-activity monitoring, the electrohysterographic (EHG) measurement and interpretation remain challenging. In particular, little attention has been paid to the analysis of the EHG propagation, whose characteristics might be predictive of the preterm delivery. Therefore, this paper focuses, for the first time, on the noninvasive estimation of the conduction velocity of the EHG-action potentials. To this end, multichannel EHG recording and surface high-density electrodes are used. A maximum-likelihood method is employed for analyzing the EHG-action-potential propagation in two dimensions. The use of different weighting strategies of the derived cost function is introduced to deal with the poor signal similarity between different channels. The presented methods were evaluated by specific simulations proving the best weighting strategy to lead to an accuracy improvement of 56.7%. EHG measurements on ten women with uterine contractions confirmed the feasibility of the method by leading to conduction velocity values within the expected physiological range.

On the nature of the electromyographic signals recorded during vibration exercise

“…The MF can be estimated as the first statistical moment of the EMG amplitude spectrum (Merletti et al 1990). The CV of the motor unit action potentials along the muscle fibers can be estimated using two or more recording electrodes placed on the skin along the muscle fibers with known inter-electrode distance (Hunter et al 1987;Farina and Merletti 2004;Farina and Negro 2007;Mischi et al 2010;Rabotti et al 2010).…”

Analogue Frontend Amplifiers for Bio-Potential Measurements Manufactured With a-IGZO TFTs on Flexible Substrate

“…One example is described by Rabotti et al in [1], where a matrix of passive electrodes is used to acquire electro EHG signals. These signals are used to monitor the uterine action potential conduction velocity, in order to predict preterm labour of pregnant women.…”

“…A matrix of electrodes on foils with embedded a-IGZO TFT bio-potential amplifiers would be an excellent approach to ensure wearability and comfort of use in this application. In [1] it has been shown that it is possible to extract conduction velocity with very good accuracy from signals having an SNR of 5.88 dB. Here the SNR is expressed as:…”

“…Another interesting application is presented in [1], where the electro hysterogram (electrical activity due to the uterus contractions -EHG) is monitored by a matrix of electrodes placed on top of the abdomen of pregnant women. From the analysis of the EHG signals over a certain area the contraction conduction velocity can be extracted, which can be used to estimate preterm delivery with high accuracy.…”

Combining data fusion with multiresolution analysis for improving the classification accuracy of uterine EMG signals

“…New parameters were derived from the multichannel recordings. In particular, synchronization [9][10][11][12] and propagation velocity [13][14][15][16] of the electrical activity of the uterine muscle were proven to be efficient tools to diagnose labor. Moreover, in terms of classification of uterine EMG signals, it was proven that the use of a data fusion-based approach can outperform the classification based on the use of a single electrodes [17,18].…”