Raised electrical uterine activity and shortened cervical length could predict preterm delivery in a low-risk population

PURPOSE: To compare diagnostic accuracy of sonographic cervical length (CL) measurement and uterine electric activity assessed by electromyography (EMG) in second trimester regarding prediction of preterm delivery (PTD). ----- METHODS: Prospective study of 308 low-risk women. Shortened CL was defined as ≤25 mm (≤5th centile), while raised EMG activity was defined as the presence of ≥20 action potentials in 20 min of assessment (≥95th centile). Outcome measures were diagnostic accuracy of both tests alone or in combination for prediction of PTD and early PTD (≤34 weeks). ----- RESULTS: The incidence of PTD was 23/308 (7.4%) while the incidence of early PTD was 9/308 (2.9%). Shortened CL and raised EMG activity were significantly related to PTD [prevalence-weighted likelihood ratio (pw-LR) 1.9, 95% CI 1.0-3.5 vs. 9.5, 95% CI 2.5-35.7], but not to early PTD (pw-LR 0.4, 95% CI 0.2-0.8 vs. 0.6, 95% CI 0.3-1.7). Significant predictive value for early PTD was found only if both tests were combined (pw-LR 4, 95% CI 1.3-14.3). ----- CONCLUSION: Shortened CL and raised EMG activity in second trimester have significant diagnostic accuracy regarding prediction of PTD in a low-risk population. However, in order to be useful as a predictor for early PTD both tests must be positive

A node-wise analysis of the uterine muscle networks for pregnancy monitoring

The recent past years have seen a noticeable increase of interest in the correlation analysis of electrohysterographic (EHG) signals in the perspective of improving the pregnancy monitoring. Here we propose a new approach based on the functional connectivity between multichannel (4x4 matrix) EHG signals recorded from the women abdomen. The proposed pipeline includes i) the computation of the statistical couplings between the multichannel EHG signals, ii) the characterization of the connectivity matrices, computed by using the imaginary part of the coherence, based on the graph-theory analysis and iii) the use of these measures for pregnancy monitoring. The method was evaluated on a dataset of EHGs, in order to track the correlation between EHGs collected by each electrode of the matrix (called node-wise analysis) and follow their evolution along weeks before labor. Results showed that the strength of each node significantly increases from pregnancy to labor. Electrodes located on the median vertical axis of the uterus seemed to be the more discriminant. We speculate that the network-based analysis can be a very promising tool to improve pregnancy monitoring.Comment: 4 pages, 3 figures, accepted in the IEEE EMBC conferanc

Recurring patterns in stationary intervals of abdominal uterine electromyograms during gestation

Abdominal uterine electromyograms (uEMG) studies have focused on uterine contractions to describe the evolution of uterine activity and preterm birth (PTB) prediction. Stationary, non-contracting uEMG has not been studied. The aim of the study was to investigate the recurring patterns in stationary uEMG, their relationship with gestation age and PTB, and PTB predictivity. A public database of 300 (38 PTB) three-channel (S1-S3) uEMG recordings of 30 min, collected between 22 and 35 weeks' gestation, was used. Motion and labour contraction-free intervals in uEMG were identified as 5-min weak-sense stationarity intervals in 268 (34 PTB) recordings. Sample entropy (SampEn), percentage recurrence (PR), percentage determinism (PD), entropy (ER), and maximum length (L MAX) of recurrence were calculated and analysed according to the time to delivery and PTB. Random time series were generated by random shuffle (RS) of actual data. Recurrence was present in actual data (p<0.001) but not RS. In S3, PR (p<0.005), PD (p<0.01), ER (p<0.005), and L MAX (p<0.05) were higher, and SampEn lower (p<0.005) in PTB. Recurrence indices increased (all p<0.001) and SampEn decreased (p<0.01) with decreasing time to delivery, suggesting increasingly regular and recurring patterns with gestation progression. All indices predicted PTB with AUC≥0.62 (p<0.05). Recurring patterns in stationary non-contracting uEMG were associated with time to delivery but were relatively poor predictors of PTB

Preterm labour detection by use of a biophysical marker: the uterine electrical activity

<p>Abstract</p> <p>Background</p> <p>The electrical activity of the uterine muscle is representative of uterine contractility. Its characterization may be used to detect a potential risk of preterm delivery in women, even at an early gestational stage.</p> <p>Methods</p> <p>We have investigated the effect of the recording electrode position on the spectral content of the signal by using a mathematical model of the women's abdomen. We have then compared the simulated results to actual recordings. On signals with noise reduced with a dedicated algorithm, we have characterized the main frequency components of the signal spectrum in order to compute parameters indicative of different situations: preterm contractions resulting nonetheless in term delivery (i.e. normal contractions) and preterm contractions leading to preterm delivery (i.e. high-risk contractions). A diagnosis system permitted us to discriminate between these different categories of contractions. As the position of the placenta seems to affect the frequency content of electrical activity, we have also investigated in monkeys, with internal electrodes attached on the uterus, the effect of the placenta on the spectral content of the electrical signals.</p> <p>Results</p> <p>In women, the best electrode position was the median vertical axis of the abdomen. The discrimination between high risk and normal contractions showed that it was possible to detect a risk of preterm labour as early as at the 27th week of pregnancy (Misclassification Rate range: 11–19.5%). Placental influence on electrical signals was evidenced in animal recordings, with higher energy content in high frequency bands, for signals recorded away from the placenta when compared to signals recorded above the placental insertion. However, we noticed, from pregnancy to labour, a similar evolution of the frequency content of the signal towards high frequencies, whatever the relative position of electrodes and placenta.</p> <p>Conclusion</p> <p>On human recordings, this study has proved that it is possible to detect, by non-invasive abdominal recordings, a risk of preterm birth as early as the 27th week of pregnancy. On animal signals, we have evidenced that the placenta exerts a local influence on the characteristics of the electrical activity of the uterus. However, these differences have a small influence on premature delivery risk diagnosis when using proper diagnosis tools.</p

Feasibility and analysis of bipolar concentric recording of Electrohysterogram with flexible active electrode

The conduction velocity and propagation patterns of Electrohysterogram (EHG) provide fundamental information about uterine electrophysiological condition. The accuracy of these measurements can be impaired by both the poor spatial selectivity and sensitivity to the relative direction of the contraction propagation associated with conventional disc electrodes. Concentric ring electrodes could overcome these limitations the aim of this study was to examine the feasibility of picking up surface EHG signals using a new flexible tripolar concentric ring electrode (TCRE), and to compare it with conventional bipolar recordings. Simultaneous recording of conventional bipolar signals and bipolar concentric EHG (BC-EHG) were carried out on 22 pregnant women. Signal bursts were characterized and compared. No significant differences among channels in either duration or dominant frequency in the Fast Wave High frequency range were found. Nonetheless, the high pass filtering effect of the BC-EHG records resulted in lower frequency content within the range 0.1 to 0.2 Hz than the bipolar ones. Although the BC-EHG signal amplitude was about 5-7 times smaller than that of bipolar recordings, similar signal-to-noise ratio was obtained. These results suggest that the flexible TCRE is able to pick up uterine electrical activity and could provide additional information for deducing uterine electrophysiological condition.The authors are grateful to the Obstetrics Unit of the Hospital Universitario La Fe de Valencia (Valencia, Spain), where the recording sessions were carried out. The work was supported in part by the Ministerio de Ciencia y Tecnologia de Espana (TEC2010-16945), by the Universitat Politecnica de Valencia (PAID SP20120490) and Generalitat Valenciana (GV/2014/029) and by General Electric Healthcare.Ye Lin, Y.; Alberola Rubio, J.; Prats Boluda, G.; Perales Marin, AJ.; Desantes, D.; Garcia Casado, FJ. (2015). Feasibility and analysis of bipolar concentric recording of Electrohysterogram with flexible active electrode. Annals of Biomedical Engineering. 43(4):968-976. https://doi.org/10.1007/s10439-014-1130-5S968976434Alberola-Rubio, J., G. Prats-Boluda, Y. Ye-Lin, J. Valero, A. Perales, and J. Garcia-Casado. Comparison of non-invasive electrohysterographic recording techniques for monitoring uterine dynamics. Med. Eng. Phys. 35(12):1736–1743, 2013.Besio, W. G., K. Koka, R. Aakula, and W. Dai. Tri-polar concentric ring electrode development for laplacian electroencephalography. IEEE Trans. Biomed. Eng. 53(5):926–933, 2006.Devasahayam, S. R. Signals and Systems in Biomedical Engineering. Berlin: Springer, 2013.Devedeux, D., C. Marque, S. Mansour, G. Germain, and J. Duchene. Uterine electromyography: a critical review. Am. J. Obstet. Gynecol. 169(6):1636–1653, 1993.Estrada, L., A. Torres, J. Garcia-Casado, G. Prats-Boluda, and R. Jane. Characterization of laplacian surface electromyographic signals during isometric contraction in biceps brachii. Conf. Proc. IEEE Eng Med. Biol. Soc. 2013:535–538, 2013.Euliano, T. Y., D. Marossero, M. T. Nguyen, N. R. Euliano, J. Principe, and R. K. Edwards. Spatiotemporal electrohysterography patterns in normal and arrested labor. Am. J. Obstet. Gynecol. 200(1):54–57, 2009.Farina, D., and C. Cescon. Concentric-ring electrode systems for noninvasive detection of single motor unit activity. IEEE Trans. Biomed. Eng. 48(11):1326–1334, 2001.Fele-Zorz, G., G. Kavsek, Z. Novak-Antolic, and F. Jager. A comparison of various linear and non-linear signal processing techniques to separate uterine EMG records of term and pre-term delivery groups. Med. Biol. Eng Comput. 46(9):911–922, 2008.Garfield, R. E., and W. L. Maner. Physiology and electrical activity of uterine contractions. Semin. Cell Dev. Biol. 18(3):289–295, 2007.Garfield, R. E., W. L. Maner, L. B. Mackay, D. Schlembach, and G. R. Saade. Comparing uterine electromyography activity of antepartum patients vs. term labor patients. Am. J. Obstet. Gynecol. 193(1):23–29, 2005.Garfield, R. E., H. Maul, L. Shi, W. Maner, C. Fittkow, G. Olsen, and G. R. Saade. Methods and devices for the management of term and preterm labor. Ann. N. Y. Acad. Sci. 943(1):203–224, 2001.Hassan, M., J. Terrien, C. Muszynski, A. Alexandersson, C. Marque, and B. Karlsson. Better pregnancy monitoring using nonlinear correlation analysis of external uterine electromyography. IEEE Trans. Biomed. Eng. 60(4):1160–1166, 2013.Kaufer, M., L. Rasquinha, and P. Tarjan. Optimization of multi-ring sensing electrode set, Conference proceedings of IEEE Engineering in Medicine and Biology Society, 1990, pp. 612–613.Koka, K., and W. G. Besio. Improvement of spatial selectivity and decrease of mutual information of tri-polar concentric ring electrodes. J. Neurosci. Methods 165(2):216–222, 2007.Lu, C.-C., and P. P. Tarjan. Pasteless, active, concentric ring sensors for directly obtained laplacian cardiac electrograms. J. Med. Biol. Eng. 22(4):199–203, 2002.Lucovnik, M., W. L. Maner, L. R. Chambliss, R. Blumrick, J. Balducci, Z. Novak-Antolic, and R. E. Garfield. Noninvasive uterine electromyography for prediction of preterm delivery. Am. J. Obstet. Gynecol. 204(3):228.e1–228.e10, 2011.Maner, W. L., and R. E. Garfield. Identification of human term and preterm labor using artificial neural networks on uterine electromyography data. Ann. Biomed. Eng. 35(3):465–473, 2007.Maner, W. L., R. E. Garfield, H. Maul, G. Olson, and G. Saade. Predicting term and preterm delivery with transabdominal uterine electromyography. Obstet. Gynecol. 101(6):1254–1260, 2003.Marque, C., J. M. Duchene, S. Leclercq, G. S. Panczer, and J. Chaumont. Uterine EHG processing for obstetrical monitoring. IEEE Trans. Biomed. Eng. 33(12):1182–1187, 1986.Marque, C. K., J. Terrien, S. Rihana, and G. Germain. Preterm labour detection by use of a biophysical marker: the uterine electrical activity. BMC. Pregnancy Childbirth. 7(Suppl1):S5, 2007.Maul, H., W. L. Maner, G. Olson, G. R. Saade, and R. E. Garfield. Non-invasive transabdominal uterine electromyography correlates with the strength of intrauterine pressure and is predictive of labor and delivery. J. Matern. Fetal Neonatal Med. 15(5):297–301, 2004.Miles, A. M., M. Monga, and K. S. Richeson. Correlation of external and internal monitoring of uterine activity in a cohort of term patients. Am. J. Perinatol. 18(3):137–140, 2001.Prats-Boluda, G., J. Garcia-Casado, J. L. Martinez-de-Juan, and Y. Ye-Lin. Active concentric ring electrode for non-invasive detection of intestinal myoelectric signals. Med. Eng. Phys. 33(4):446–455, 2010.Prats-Boluda, G., Y. Ye-Lin, E. Garcia-Breijo, J. Ibañez, and J. Garcia-Casado. Active flexible concentric ring electrode for non-invasive surface bioelectrical recordings. Meas. Sci. Technol. 23(12):1–10, 2012.Rabotti, C., M. Mischi, S. G. Oei, and J. W. Bergmans. Noninvasive estimation of the electrohysterographic action-potential conduction velocity. IEEE Trans. Biomed. Eng. 57(9):2178–2187, 2010.Rabotti, C., S. G. Oei, H. J. van ‘t, and M. Mischi. Electrohysterographic propagation velocity for preterm delivery prediction. Am. J. Obstet. Gynecol. 205(6):e9–e10, 2011.Rooijakkers, M. J., S. Song, C. Rabotti, S. G. Oei, J. W. Bergmans, E. Cantatore, and M. Mischi. Influence of electrode placement on signal quality for ambulatory pregnancy monitoring. Comput. Math. Methods Med. 2014(1):960980, 2014.Schlembach, D., W. L. Maner, R. E. Garfield, and H. Maul. Monitoring the progress of pregnancy and labor using electromyography. Eur. J. Obstet. Gynecol. Reprod. Biol. 144(Suppl1):S33–S39, 2009.Sikora, J., A. Matonia, R. Czabanski, K. Horoba, J. Jezewski, and T. Kupka. Recognition of premature threatening labour symptoms from bioelectrical uterine activity signals. Arch. Perinatal Med. 17(2):97–103, 2011.Terrien, J., C. Marque, and B. Karlsson. Spectral characterization of human EHG frequency components based on the extraction and reconstruction of the ridges in the scalogram, Conference proceedings of IEEE Engineering in Medicine and Biology Society, 2007, pp. 1872–1875.Terrien, J., C. Marque, T. Steingrimsdottir, and B. Karlsson. Evaluation of adaptive filtering methods on a 16 electrode electrohysterogram recorded externally in labor, 11th Mediterranean Conference on Medical and Biomedical Engineering and Computing, 2007, Vol. 16, pp. 135–138.U.S. Preventive Services Task Force. Guide to clinical preventive services: an assessment of the effectiveness of 169 interventions. Baltimore: Willams & Wilkins, 1989

Enhancement of Non-Invasive Recording of Electroenterogram by Means of a Flexible Array of Concentric Ring Electrodes

Monitoring intestinal myoelectrical activity by electroenterogram (EEnG) would be of great clinical interest for diagnosing gastrointestinal pathologies and disorders. However, surface EEnG recordings are of very low amplitude and can be severely affected by baseline drifts and respiratory and electrocardiographic (ECG) interference. In this work, a flexible array of concentric ring electrodes was developed and tested to determine whether it can provide surface EEnG signals of better quality than bipolar recordings from conventional disc electrodes. With this aime, sixteen healthy subjects in a fasting state (>8h) underwent recording. The capabiltiy of detecting intestinal pacemaker activity (slow wave) and the influence of physiological interferences were studied. The signals obtained from the concentric ring electrodes proved to be more robust to ECG and respiratory interference than those from conventional disc electrodes. The results also show that intestinal EEnG components such as the slow wave can be more easily identified by the proposed system based on a flexible array of concentric ring electrodes. The developed active electrode array could be a very valuable tool for non-invasive diagnosis of disease states such as ischemia and motility disorders of the small bowel which are known to alter the normal enteric slow wave activity.Research supported in part by the Ministerio de Ciencia y Tecnologia de Espana (TEC 2010-16945). The proof-reading of this paper was funded by the Universitat Politecnica de Valencia, Spain.Garcia Casado, FJ.; Zena Giménez, VF.; Prats Boluda, G.; Ye Lin, Y. (2014). Enhancement of Non-Invasive Recording of Electroenterogram by Means of a Flexible Array of Concentric Ring Electrodes. Annals of Biomedical Engineering. 42(3):651-660. https://doi.org/10.1007/s10439-013-0935-yS651660423Abo, M., J. Liang, L. Qian, and J. D. Chen. Distension-induced myoelectrical dysrhythmia and effect of intestinal pacing in dogs. Dig. Dis. Sci. 45(1):129–135, 2000.Besio, W., R. Aakula, K. Koka, and W. Dai. Development of a tri-polar concentric ring electrode for acquiring accurate Laplacian body surface potentials. Ann. Biomed. Eng. 34(3):426–435, 2006.Besio, W., and T. Chen. Tripolar Laplacian electrocardiogram and moment of activation isochronal mapping. Physiol. Meas. 28(5):515–529, 2007.Bradshaw, L. A., S. H. Allos, J. P. Wikswo, Jr, and W. O. Richards. Correlation and comparison of magnetic and electric detection of small intestinal electrical activity. Am. J. Physiol. 272(5 Pt 1):G1159–G1167, 1997.Bradshaw, L. A., J. K. Ladipo, D. J. Staton, J. P. Wikswo, Jr, and W. O. Richards. The human vector magnetogastrogram and magnetoenterogram. IEEE Trans. Biomed. Eng. 46(8):959–970, 1999.Bradshaw, L. A., W. O. Richards, and J. P. Wikswo, Jr. Volume conductor effects on the spatial resolution of magnetic fields and electric potentials from gastrointestinal electrical activity. Med. Biol. Eng Comput. 39(1):35–43, 2001.Caenepeel, P., W. Janssens, A. Accarino, J. Janssens, G. Vantrappen, and H. Eyssen. Variation of slow-wave frequency and locking during the migrating myoelectric complex in dogs. Am. J. Physiol. 261(6):G1079–G1084, 1991.Chang, F. Y., C.-L. Lu, C.-Y. Chen, J.-C. Luo, S.-D. Lee, H.-C. Wu, and J. D. Z. Chen. Fasting and postprandial small intestinal slow waves non-invasively measured in subjects with total gastrectomy. Gastroenterology 22:247–252, 2006.Chen, J. D. Z. Non-invasive measurement of gastric myoelectrical activity and its analysis and applications. In: Annual International Conference of the IEEE Engineering in Medicine and Biology Society, Vol. 20, 1998, pp. 2802–2807.Chen, J. D. Z., D. Schirmer, and R. W. McCallum. Measurement of electric activity of the human small intestine using surface electrodes. IEEE Trans. Biomed. Eng. 40(6):598–602, 1993.Clifton, J. A., J. Christensen, and H. P. Schedl. The human small intestinal slow wave. Trans. Am. Clin. Climatol. Assoc. 77:217–225, 1966.Feltane, A., G. F. Boudreaux-Bartels, and W. Besio. Automatic seizure detection in rats using Laplacian EEG and verification with human seizure signals. Ann. Biomed. Eng. 41(3):645–654, 2013.Fleckenstein, P., and A. Oigaard. Electrical spike activity in the human small intestine. A multiple electrode study of fasting diurnal variations. Am. J. Dig. Dis. 23(9):776–780, 1978.Garcia-Casado, J., J. L. Martinez-de-Juan, and J. L. Ponce. Noninvasive measurement and analysis of intestinal myoelectrical activity using surface electrodes. IEEE Trans. Biomed. Eng. 52(6):983–991, 2005.Garcia-Casado, J., J. L. Martinez-de-Juan, and J. L. Ponce. Adaptive filtering of ECG interference on surface EEnGs based on signal averaging. Physiol. Meas. 27(6):509–527, 2006.Gruetzmann, A., S. Hansen, and J. Muller. Novel dry electrodes for ECG monitoring. Physiol. Meas. 28(11):1375–1390, 2007.He, B., and R. J. Cohen. Body surface Laplacian mapping of cardiac electrical activity. Am. J. Cardiol. 70(20):1617–1620, 1992.Koka, K., and W. G. Besio. Improvement of spatial selectivity and decrease of mutual information of tri-polar concentric ring electrodes. J. Neurosci. Methods 165(2):216–222, 2007.Lammers, W. J., H. M. Al-Bloushi, S. A. Al-Eisae, F. A. Al-Dhaheri, B. Stephen, R. John, S. Dhanasekaran, and M. Karam. Slow wave propagation and plasticity of interstitial cells of Cajal in the small intestine of diabetic. Exp. Physiol. 96:1039–1048, 2011.Li, G., Y. Wang, W. Jiang, L. L. Wang, C.-Y. S. Lu, and W. G. Besio. Active Laplacian electrode for the data-acquisition system of EHG. J. Phys: Conf. Ser. 13:330–335, 2005.Li, G. L., J. Lian, P. Salla, J. Cheng, I. Ramachandra, P. Shah, B. Avitall, and B. He. Body surface Laplacian electrocardiogram of ventricular depolarization in normal human subjects. J. Cardiovasc. Electrophysiol. 14(1):16–27, 2003.Lian, J., G. Li, J. Cheng, B. Avitall, and B. He. Body surface Laplacian mapping of atrial depolarization in healthy human subjects. Med. Biol. Eng Comput. 40(6):650–659, 2002.Lin, Z. Y., and J. D. Z. Chen. Recursive running DCT algorithm and its application in adaptive filtering of surface electrical recording of small-intestine. Med. Biol. Eng. Comput. 32(3):317–322, 1994.Lindh, W. Q., M. Pooler, C. D. Tamparo, B. M. Dahl, and J. Morris. Delmar’s Comprehensive Medical Assisting: Administrative and Clinical Competencies. Clifton Park, NY: Delmar Cengage Learning, p. 573, 2009.Madl, C., and W. Druml. Gastrointestinal disorders of the critically ill. Systemic consequences of ileus. Best. Pract. Res. Clin. Gastroenterol. 17(3):445–456, 2003.Merletti, R. Standards for reporting EMG data. J. Electromyography Kinesiol. 9(1):III–IV, 1999.Morrison, P., B. W. Miedema, L. Kohler, and K. A. Kelly. Electrical rysrhythmias in the Roux jejunal limb—cause and treatment. Am. J. Surg. 160(3):252–256, 1990.Park, H. The pathophysiology of irritable bowel syndrome: inflammation and motor disorder. Korean J. Gastroenterol. 47(2):101–110, 2006.Prats-Boluda, G., J. Garcia-Casado, J. L. Martinez-de-Juan, and J. L. Ponce. Identification of the slow wave component of the electroenterogram from Laplacian abdominal surface recordings in humans. Physiol. Meas. 28(9):1115–1133, 2007.Prats-Boluda, G., J. Garcia-Casado, J. L. Martinez-de-Juan, and Y. Ye-Lin. Active concentric ring electrode for non-invasive detection of intestinal myoelectric signals. Med. Eng. Phys. 33(4):446–455, 2011.Prats-Boluda, G., Y. Ye-Lin, E. Garcia-Breijó, J. Ibañez, and J. Garcia-Casado. Active flexible concentric ring electrode for noninvasive surface bioelectrical recordings. Meas. Sci. Technol. 23(125703):1–10, 2012.Saito, Y. A., P. R. Strege, D. J. Tester, G. R. Locke, N. J. Talley, C. E. Bernard, J. L. Rae, J. C. Makielski, M. J. Ackerman, and G. Farrugia. Sodium channel mutation in irritable bowel syndrome: evidence for an ion channelopathy. Am. J. Physiol. Gastrointest. Liver Physiol. 296(2):G211–G218, 2009.Shafik, A., A. A. Shafik, O. El Sibai, and I. Ahmed. Colonic pacing in patients with constipation due to colonic inertia. Med. Sci. Monit. 9(5):191–196, 2003.Somarajan, S., S. Cassilly, C. Obioha, L. Bradshaw, and W. Richards. Noninvasive biomagnetic detection of isolated ischemic bowel segments. IEEE Trans. Biomed. Eng. 60(6):1677–1684, 2013.Soundararajan, V., and W. Besio. Simulated comparison of disc and concentric electrode maps during atrial arrhythmias. Int. J. Bioelectromagn 7(1):217–220, 2005.Summers, R. W., S. Anuras, and J. Green. Jejunal manometry patterns in health, partial intestinal obstruction, and pseudoobstruction. Gastroenterology 85(6):1290–1300, 1983.Webster, J. G., J. W. Clark, Jr., M. R. Neuman, W. H. Olson, R. A. Peura, F. P. J. Primiano, M. P. Siedband, and L. A. Wheeler. Medical Instrumentation Application and Design. NewYork: Wiley, 1998.Weisbrodt, N. W. Motility of the small intestine. In: Physiology of the Gastrointestinal Tract, edited by L. R. Johnson. New York: Raven Press, 1987, pp. 631–663.Wu, D., H. C. Tsai, and B. He. On the estimation of the Laplacian electrocardiogram during ventricular activation. Ann. Biomed. Eng. 27(6):731–745, 1999.Ye-Lin, Y., J. Garcia-Casado, J. L. Martinez-de-Juan, G. Prats-Boluda, and J. L. Ponce. The detection of intestinal spike activity on surface electroenterograms. Phys. Med. Biol. 55(3):663–680, 2010.Ye-Lin, Y., J. Garcia-Casado, G. Prats-Boluda, J. L. Ponce, and J. L. Martinez-de-Juan. Enhancement of the non-invasive electroenterogram to identify intestinal pacemaker activity. Physiol. Meas. 30(9):885–902, 2009

Assessment of Features between Multichannel Electrohysterogram for Differentiation of Labors

[EN] Electrohysterogram (EHG) is a promising method for noninvasive monitoring of uterine electrical activity. The main purpose of this study was to characterize the multichannel EHG signals to distinguish between term delivery and preterm birth, as well as deliveries within and beyond 24 h. A total of 219 pregnant women were grouped in two ways: (1) term delivery (TD), threatened preterm labor (TPL) with the outcome of preterm birth (TPL_PB), and TPL with the outcome of term delivery (TPL_TD); (2) EHG recording time to delivery (TTD) 24 h. Three bipolar EHG signals were analyzed for the 30 min recording. Six EHG features between multiple channels, including multivariate sample entropy, mutual information, correlation coefficient, coherence, direct partial Granger causality, and direct transfer entropy, were extracted to characterize the coupling and information flow between channels. Significant differences were found for these six features between TPL and TD, and between TTD 24 h. No significant difference was found between TPL_PB and TPL_TD. The results indicated that EHG signals of TD were more regular and synchronized than TPL, and stronger coupling between multichannel EHG signals was exhibited as delivery approaches. In addition, EHG signals propagate downward for the majority of pregnant women regardless of different labors. In conclusion, the coupling and propagation features extracted from multichannel EHG signals could be used to differentiate term delivery and preterm birth and may predict delivery within and beyond 24 h.This research was funded by the National Key R&D Program, grant number 2019YFC0119700, and the National Natural Science Foundation of China, grant number U20A20388.Zhang, Y.; Hao, D.; Yang, L.; Zhou, X.; Ye Lin, Y.; Yang, Y. (2022). Assessment of Features between Multichannel Electrohysterogram for Differentiation of Labors. Sensors. 22(9):1-18. https://doi.org/10.3390/s2209335211822

Use of Uterine Electromyography (EMG) for Estimation of Uterine Contractility and Cervical Dilation During the 1st Stage Labor in Pregnant Women

A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine.Labor and delivery in pregnant women occurs in three stages: The 1st stage begins with the onset of uterine contractility and progressive cervical dilation. The onset and development of labor are commonly monitored with crude and inaccurate instruments and methods: a force transducer (tocodynamometer or TOCO) strapped to the abdominal surface to measure uterine contractility and digital exams to estimate effacement and cervical dilation. Electrical activity is the underlying basis for uterine contractility as it is in all muscles including the heart, skeletal and smooth muscles and electrical activity can be accurately estimated with electromyography (EMG, electrophysiological methods). In the uterus, electrical activity consists of bursts of spikes and the characteristics of the bursts are responsible for the frequency, duration and force of contractions. The goals of this study were to assess: 1) The potential for measuring uterine electrical activity during the 1st stage of labor as the basis for contractility of the uterus; 2) The causal relationship of contractility to and changes in cervical effacement and dilation in pregnant patients , and 3) Define how predicted values of cervical dilation can be obtained from electrical signals and how predicted values of electrical signal characteristics can be obtained from cervical dilation.This item is part of the College of Medicine - Phoenix Scholarly Projects 2019 collection. For more information, contact the Phoenix Biomedical Campus Library at [email protected]

Electrohysterography in the diagnosis of preterm birth: a review

This is an author-created, un-copyedited versíon of an article published in Physiological Measurement. IOP Publishing Ltd is not responsíble for any errors or omissíons in this versíon of the manuscript or any versíon derived from it. The Versíon of Record is available online at http://doi.org/10.1088/1361-6579/aaad56.[EN] Preterm birth (PTB) is one of the most common and serious complications in pregnancy. About 15 million preterm neonates are born every year, with ratios of 10-15% of total births. In industrialized countries, preterm delivery is responsible for 70% of mortality and 75% of morbidity in the neonatal period. Diagnostic means for its timely risk assessment are lacking and the underlying physiological mechanisms are unclear. Surface recording of the uterine myoelectrical activity (electrohysterogram, EHG) has emerged as a better uterine dynamics monitoring technique than traditional surface pressure recordings and provides information on the condition of uterine muscle in different obstetrical scenarios with emphasis on predicting preterm deliveries. Objective: A comprehensive review of the literature was performed on studies related to the use of the electrohysterogram in the PTB context. Approach: This review presents and discusses the results according to the different types of parameter (temporal and spectral, non-linear and bivariate) used for EHG characterization. Main results: Electrohysterogram analysis reveals that the uterine electrophysiological changes that precede spontaneous preterm labor are associated with contractions of more intensity, higher frequency content, faster and more organized propagated activity and stronger coupling of different uterine areas. Temporal, spectral, non-linear and bivariate EHG analyses therefore provide useful and complementary information. Classificatory techniques of different types and varying complexity have been developed to diagnose PTB. The information derived from these different types of EHG parameters, either individually or in combination, is able to provide more accurate predictions of PTB than current clinical methods. However, in order to extend EHG to clinical applications, the recording set-up should be simplified, be less intrusive and more robust-and signal analysis should be automated without requiring much supervision and yield physiologically interpretable results. Significance: This review provides a general background to PTB and describes how EHG can be used to better understand its underlying physiological mechanisms and improve its prediction. The findings will help future research workers to decide the most appropriate EHG features to be used in their analyses and facilitate future clinical EHG applications in order to improve PTB prediction.This work was supported by the Spanish Ministry of Economy and Competitiveness and the European Regional Development Fund under grant DPI2015-68397-R.Garcia-Casado, J.; Ye Lin, Y.; Prats-Boluda, G.; Mas-Cabo, J.; Alberola Rubio, J.; Perales Marin, AJ. (2018). Electrohysterography in the diagnosis of preterm birth: a review. Physiological Measurement. 39(2). https://doi.org/10.1088/1361-6579/aaad56S39