Assessment of Muscle Coordination Changes Caused by the Use of an Occupational Passive Lumbar Exoskeleton in Laboratory Conditions

[EN] The introduction of exoskeletons in industry has focused on improving worker safety. Exoskeletons have the objective of decreasing the risk of injury or fatigue when performing physically demanding tasks. Exoskeletons' effect on the muscles is one of the most common focuses of their assessment. The present study aimed to analyze the muscle interactions generated during load-handling tasks in laboratory conditions with and without a passive lumbar exoskeleton. The electromyographic data of the muscles involved in the task were recorded from twelve participants performing load-handling tasks. The correlation coefficient, coherence coefficient, mutual information, and multivariate sample entropy were calculated to determine if there were significant differences in muscle interactions between the two test conditions. The results showed that muscle coordination was affected by the use of the exoskeleton. In some cases, the exoskeleton prevented changes in muscle coordination throughout the execution of the task, suggesting a more stable strategy. Additionally, according to the directed Granger causality, a trend of increasing bottom-up activation was found throughout the task when the participant was not using the exoskeleton. Among the different variables analyzed for coordination, the most sensitive to changes was the multivariate sample entropy.This study was funded by Fundación Prevent.Iranzo-Egea, S.; Belda-Lois, J.; Martínez-De-Juan, JL.; Prats-Boluda, G. (2023). Assessment of Muscle Coordination Changes Caused by the Use of an Occupational Passive Lumbar Exoskeleton in Laboratory Conditions. Sensors. 23(24):1-14. https://doi.org/10.3390/s23249631114232

A Surface Electromyogram Evaluation of the Postural Freedom Effects in Laparoscopic Surgery

[EN] It has been demonstrated that laparoscopic procedures benefit patients in terms of recovery time, exposure to infections and trauma. Nevertheless, it increases the number of problems for the surgeons, including the frequency and duration of awkward postures for surgeons. The repetition of these movements is considered the main cause for musculoskeletal disorders in surgeons' upper limbs. The goal of this study is to evaluate the muscular activity and muscular fatigue effect produced by both, a conventional instrument and an instrument provided with the Postural Freedom (PF) feature; which consists in a ball socket articulation that allows a variable handle-to-shaft angle, on a conventional laparoscopic pistol-grip handle. Seventeen participants were evaluated during a static simulation using both instruments. Surface electromyography was used to compare the instruments in terms of muscular activity in each target position and muscular fatigue produced in the muscles trapezius, deltoids, biceps, and flexor carpi radialis. Trapezius and deltoids were the muscles most affected. Entrance and exit targets and targets facing the participants showed the higher muscular activity values. The PF prototype reduced muscular activity in all the muscles and in the majority of the target positions showing a reduction greater than 70% of the activity required by the trapezius and deltoid muscles in comparison to the conventional tool. Muscular fatigue was produced by both instruments but it presented lower frequency values with PF prototype. The results indicated that the use of conventional instruments impacts negatively on muscular activity during laparoscopic procedures, in terms of positions adopted. The PF feature in laparoscopic instrumentation reduced the muscular activity and also decreased the signals of muscular fatigue in the muscles evaluated in comparison with the conventional tool.Pace-Bedetti, HM.; Martínez-De-Juan, JL.; Conejero Rodilla, A.; Prats-Boluda, G. (2019). A Surface Electromyogram Evaluation of the Postural Freedom Effects in Laparoscopic Surgery. IEEE. 3143-3146. https://doi.org/10.1109/EMBC.2019.88579193143314

Enhancement of the non-invasive electroenterogram to identify intestinal pacemaker activity

Surface recording of electroenterogram (EEnG) is a non-invasive method for monitoring intestinal myoelectrical activity. However, surface EEnG is seriously affected by a variety of interferences: cardiac activity, respiration, very low frequency components and movement artefacts. The aim of this study is to eliminate respiratory interference and very low frequency components from external EEnG recording by means of empirical mode decomposition (EMD), so as to obtain more robust indicators of intestinal pacemaker activity from external EEnG signal. For this purpose, 11 recording sessions were performed in an animal model under fasting conditions and in each individual session the myoelectrical signal was recorded simultaneously in the intestinal serosa and the external abdominal surface in physiological states. Various parameters have been proposed for evaluating the efficacy of the method in reducing interferences: the signal-to-interference ratio (S/I ratio), attenuation of the target and interference signals, the normal slow wave percentage and the stability of the dominant frequency (DF) of the signal. The results show that the S/I ratio of the processed signals is significantly greater than the original values (9.66±4.44 dB vs. 1.23±5.13 dB), while the target signal was barely attenuated (-0.63±1.02 dB). The application of the EMD method also increased the percentage of the normal slow wave to 100% in each individual session and enabled the stability of the DF of the external signal to be increased considerably. Furthermore, the variation coefficient of the DF derived from the external processed signals is comparable to the coefficient obtained using internal recordings. Therefore the EMD method could be a very useful tool to improve the quality of external EEnG recording in the low frequency range, and therefore to obtain more robust indicators of the intestinal pacemaker activity from non invasive EEnG recordingsThe authors would like to thank D Alvarez-Martinez, Dr C Vila and the Veterinary Unit of the Research Centre of 'La Fe' University Hospital (Valencia, Spain), where the surgical interventions and recording sessions were carried out, and the R+D+I Linguistic Assistance Office at the UPV for their help in revising this paper. This research study was sponsored by the Ministerio de Ciencia y Tecnologia de Espana (TEC2007-64278) and by the Universidad Politecnica de Valencia, as part of a UPV research and development Grant Programme.Ye Lin, Y.; Garcia Casado, FJ.; Prats Boluda, G.; Ponce, JL.; Martínez De Juan, JL. (2009). Enhancement of the non-invasive electroenterogram to identify intestinal pacemaker activity. PHYSIOLOGICAL MEASUREMENT. 30(9):885-902. https://doi.org/10.1088/0967-3334/30/9/002S885902309Amaris, M. A., Sanmiguel, C. P., Sadowski, D. C., Bowes, K. L., & Mintchev, M. P. (2002). Digestive Diseases and Sciences, 47(11), 2480-2485. doi:10.1023/a:1020503908304Bass, P., & Wiley, J. N. (1965). Electrical and extraluminal contractile-force activity of the duodenum of the dog. The American Journal of Digestive Diseases, 10(3), 183-200. doi:10.1007/bf02233747Bradshaw, L. A., Allos, S. H., Wikswo, J. P., & Richards, W. O. (1997). Correlation and comparison of magnetic and electric detection of small intestinal electrical activity. American Journal of Physiology-Gastrointestinal and Liver Physiology, 272(5), G1159-G1167. doi:10.1152/ajpgi.1997.272.5.g1159Camilleri, M., Hasler, W. L., Parkman, H. P., Quigley, E. M. M., & Soffer, E. (1998). Measurement of gastrointestinal motility in the GI laboratory. Gastroenterology, 115(3), 747-762. doi:10.1016/s0016-5085(98)70155-6Chen, J. D. Z., & Lin, Z. (1993). Adaptive cancellation of the respiratory artifact in surface recording of small intestinal electrical activity. Computers in Biology and Medicine, 23(6), 497-509. doi:10.1016/0010-4825(93)90097-kChen, J., & McCallum, R. W. (1991). Electrogastrography: measuremnt, analysis and prospective applications. Medical & Biological Engineering & Computing, 29(4), 339-350. doi:10.1007/bf02441653Chen, J. D. Z., Schirmer, B. D., & McCallum, R. W. (1993). Measurement of electrical activity of the human small intestine using surface electrodes. IEEE Transactions on Biomedical Engineering, 40(6), 598-602. doi:10.1109/10.237682Garcia-Casado, J., Martinez-de-Juan, J. L., & Ponce, J. L. (2005). Noninvasive Measurement and Analysis of Intestinal Myoelectrical Activity Using Surface Electrodes. IEEE Transactions on Biomedical Engineering, 52(6), 983-991. doi:10.1109/tbme.2005.846730Gordon, A. D. (1987). A Review of Hierarchical Classification. Journal of the Royal Statistical Society. Series A (General), 150(2), 119. doi:10.2307/2981629Huang, N. E., Shen, Z., Long, S. R., Wu, M. C., Shih, H. H., Zheng, Q., … Liu, H. H. (1998). The empirical mode decomposition and the Hilbert spectrum for nonlinear and non-stationary time series analysis. Proceedings of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences, 454(1971), 903-995. doi:10.1098/rspa.1998.0193Irimia, A., & Bradshaw, L. A. (2005). Artifact reduction in magnetogastrography using fast independent component analysis. Physiological Measurement, 26(6), 1059-1073. doi:10.1088/0967-3334/26/6/015Lammers, W. J. E. P., & Stephen, B. (2008). Origin and propagation of individual slow waves along the intact feline small intestine. Experimental Physiology, 93(3), 334-346. doi:10.1113/expphysiol.2007.039180Liang, H. (2001). Adaptive independent component analysis of multichannel electrogastrograms. Medical Engineering & Physics, 23(2), 91-97. doi:10.1016/s1350-4533(01)00019-4Liang, J., Cheung, J. Y., & Chen, J. D. Z. (1997). Detection and deletion of motion artifacts in electrogastrogram using feature analysis and neural networks. Annals of Biomedical Engineering, 25(5), 850-857. doi:10.1007/bf02684169Liang, H., Lin, Z., & McCallum, R. W. (2000). Artifact reduction in electrogastrogram based on empirical mode decomposition method. Medical & Biological Engineering & Computing, 38(1), 35-41. doi:10.1007/bf02344686Zhi-Yue Lin, Chen, Z., & Jian De. (1994). Time-frequency representation of the electrogastrogram-application of the exponential distribution. IEEE Transactions on Biomedical Engineering, 41(3), 267-275. doi:10.1109/10.284945Lin, Z. Y., & Chen, J. D. Z. (1994). Recursive running DCT algorithm and its application in adaptive filtering of surface electrical recording of small intestine. Medical & Biological Engineering & Computing, 32(3), 317-322. doi:10.1007/bf02512529Lin, Z., & Chen, J. D. Z. (1995). Comparison of three running spectral analysis methods for electrogastrographic signals. Medical & Biological Engineering & Computing, 33(4), 596-604. doi:10.1007/bf02522520Maestri, R., Pinna, G. D., Porta, A., Balocchi, R., Sassi, R., Signorini, M. G., … Raczak, G. (2007). Assessing nonlinear properties of heart rate variability from short-term recordings: are these measurements reliable? Physiological Measurement, 28(9), 1067-1077. doi:10.1088/0967-3334/28/9/008Martinez-de-Juan, J. ., Saiz, J., Meseguer, M., & Ponce, J. . (2000). Small bowel motility: relationship between smooth muscle contraction and electroenterogram signal. Medical Engineering & Physics, 22(3), 189-199. doi:10.1016/s1350-4533(00)00032-1Mintchev, M. P., Kingma, Y. J., & Bowes, K. L. (1993). Accuracy of cutaneous recordings of gastric electrical activity. Gastroenterology, 104(5), 1273-1280. doi:10.1016/0016-5085(93)90334-9Prats-Boluda, G., Garcia-Casado, J., Martinez-de-Juan, J. L., & Ponce, J. L. (2007). Identification of the slow wave component of the electroenterogram from Laplacian abdominal surface recordings in humans. Physiological Measurement, 28(9), 1115-1133. doi:10.1088/0967-3334/28/9/012Quigley, E. M. M. (1996). GASTRIC AND SMALL INTESTINAL MOTILITY IN HEALTH AND DISEASE. Gastroenterology Clinics of North America, 25(1), 113-145. doi:10.1016/s0889-8553(05)70368-xSeidel, S. A., Bradshaw, L. A., Ladipo, J. K., Wikswo, J. P., & Richards, W. O. (1999). Noninvasive detection of ischemic bowel. Journal of Vascular Surgery, 30(2), 309-319. doi:10.1016/s0741-5214(99)70142-4Tomomasa, T., Morikawa, A., Sandler, R. H., Mansy, H. A., Koneko, H., Masahiko, T., … Itoh, Z. (1999). Gastrointestinal Sounds and Migrating Motor Complex in Fasted Humans. 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Optimized Feature Subset Selection Using Genetic Algorithm for Preterm Labor Prediction Based on Electrohysterography

[EN] Electrohysterography (EHG) has emerged as an alternative technique to predict preterm labor, which still remains a challenge for the scientific-technical community. Based on EHG parameters, complex classification algorithms involving non-linear transformation of the input features, which clinicians found difficult to interpret, were generally used to predict preterm labor. We proposed to use genetic algorithm to identify the optimum feature subset to predict preterm labor using simple classification algorithms. A total of 203 parameters from 326 multichannel EHG recordings and obstetric data were used as input features. We designed and validated 3 base classifiers based on k-nearest neighbors, linear discriminant analysis and logistic regression, achieving F1-score of 84.63 ± 2.76%, 89.34 ± 3.5% and 86.87 ± 4.53%, respectively, for incoming new data. The results reveal that temporal, spectral and non-linear EHG parameters computed in different bandwidths from multichannel recordings provide complementary information on preterm labor prediction. We also developed an ensemble classifier that not only outperformed base classifiers but also reduced their variability, achieving an F1-score of 92.04 ± 2.97%, which is comparable with those obtained using complex classifiers. Our results suggest the feasibility of developing a preterm labor prediction system with high generalization capacity using simple easy-to-interpret classification algorithms to assist in transferring the EHG technique to clinical practice.This work was supported by the Spanish Ministry of Economy and Competitiveness, the European Regional Development Fund (MCIU/AEI/FEDER, UE RTI2018-094449-A-I00-AR) and by the Generalitat Valenciana (AICO/2019/220).Nieto-Del-Amor, F.; Prats-Boluda, G.; Martínez-De-Juan, JL.; Díaz-Martínez, MDA.; Monfort-Ortiz, R.; Diago-Almela, VJ.; Ye Lin, Y. (2021). Optimized Feature Subset Selection Using Genetic Algorithm for Preterm Labor Prediction Based on Electrohysterography. Sensors. 21(10):1-15. https://doi.org/10.3390/s21103350S115211

Estudio integral de la metodología aprendizaje basado en problemas para la adquisición de competencias transversales con técnica de trabajo en equipo y evaluación individualizada

[ES] El trabajo en grupo es una de las metodologías docentes más comunes para la adquisición de competencias específicas y transversales. La metodología de aprendizaje basado en problemas (ABP) se implantó para el desarrollo grupal de competencias en los estudiantes del Grado en Ingeniería Biomédica. No obstante, se detectó una excesiva carga de trabajo no presencial para los alumnos (71±35 h). Asimismo, la evaluación del trabajo grupal no reflejaba fielmente el aprendizaje individual de cada estudiante. En este trabajo se realiza un estudio integral de la implantación de la metodología ABP con especial énfasis en la evaluación del aprendizaje individual en las actividades grupales. El análisis de la dedicación no presencial del alumnado (26±15 h por 1.8 ECTS) y del profesorado (~14.3 h/ECTS) muestra que la metodología propuesta es altamente sostenible y aunque supuso una reducción significativa en el tiempo de dedicación, no afectó a la percepción del alumnado sobre la adquisición de competencias. Además, los alumnos consideran que la metodología ABP permite mejorar significativamente el nivel de dominio del manejo de Matlab. En cuanto al sistema de evaluación que valora el aprendizaje individual del manejo de Matlab se ha encontrado cierta resistencia al cambio del método de evaluación por parte del alumnado.Este trabajo está subvencionado parcialmente por la ETSII UPV y el Vicerrectorado de Estudios, Calidad y Acreditación de la UPV (PIME B03, Convocatoria 2017-2018).Ye Lin, Y.; Prats-Boluda, G.; Bosch Roig, I.; Martínez-De-Juan, JL. (2019). Estudio integral de la metodología aprendizaje basado en problemas para la adquisición de competencias transversales con técnica de trabajo en equipo y evaluación individualizada. REDINE. 512-517. http://hdl.handle.net/10251/181094S51251

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. 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Active flexible concentric ring electrode for non-invasive surface bioelectrical recordings

Bioelectrical surface recordings are usually performed by unipolar or bipolar disc electrodes even though they entail the serious disadvantage of having poor spatial resolution. Concentric ring electrodes give improved spatial resolution, although this type of electrode has so far only been implemented in rigid substrates and as they are not adapted to the curvature of the recording surface may provide discomfort to the patient. Moreover, the signals recorded by these electrodes are usually lower in amplitude than conventional disc electrodes. The aim of this work was thus to develop and test a new modular active sensor made up of concentric ring electrodes printed on a flexible substrate by thick-film technology together with a reusable battery-powered signal-conditioning circuit. Simultaneous ECG recording with both flexible and rigid concentric ring electrodes was carried out on ten healthy volunteers at rest and in motion. The results show that flexible concentric ring electrodes not only present lower skin electrode contact impedance and lower baseline wander than rigid electrodes but are also less sensitive to interference and motion artefacts. We believe these electrodes, which allow bioelectric signals to be acquired non-invasively with better spatial resolution than conventional disc electrodes, to be a step forward in the development of new monitoring systems based on Laplacian potential recordings.This research was supported in part by the Ministerio de Ciencia y Tecnologia de Espana (TEC2010-16945) and by the Universitat Politecnica de Valencia (PAID 2009/10-2298). The proof-reading of this paper was funded by the Universitat Politecnica de Valencia, Spain.Prats Boluda, G.; Ye Lin, Y.; García Breijo, E.; Ibáñez Civera, FJ.; Garcia Casado, FJ. (2012). Active flexible concentric ring electrode for non-invasive surface bioelectrical recordings. 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Comparison of electrohysterogram signal measured by surface electrodes with different designs: A computational study with dipole band and abdomen models

Non-invasive measurement of uterine activity using electrohysterogram (EHG) surface electrodes has been attempted to monitor uterine contraction. This study aimed to computationally compare the performance of acquiring EHG signals using monopolar electrode and three types of Laplacian concentric ring electrodes (bipolar, quasi-bipolar and tri-polar). With the implementation of dipole band model and abdomen model, the performances of four electrodes in terms of the local sensitivity were quantifed by potential attenuation. Furthermore, the efects of fat and muscle thickness on potential attenuation were evaluated using the bipolar and tri-polar electrodes with diferent radius. The results showed that all the four types of electrodes detected the simulated EHG signals with consistency. That the bipolar and tri-polar electrodes had greater attenuations than the others, and the shorter distance between the origin and location of dipole band at 20dB attenuation, indicating that they had relatively better local sensitivity. In addition, ANOVA analysis showed that, for all the electrodes with diferent outer ring radius, the efects of fat and muscle on potential attenuation were signifcant (all p<0.01). It is therefore concluded that the bipolar and tri-polar electrodes had higher local sensitivity than the others, indicating that they can be applied to detect EHG efectively

Predicting Survival after Allogeneic Hematopoietic Cell Transplantation in Myelofibrosis : Performance of the Myelofibrosis Transplant Scoring System (MTSS) and Development of a New Prognostic Model

Accurate prognostic tools are crucial to assess the risk/benefit ratio of allogeneic hematopoietic cell transplantation (allo-HCT) in patients with myelofibrosis (MF). We aimed to evaluate the performance of the Myelofibrosis Transplant Scoring System (MTSS) and identify risk factors for survival in a multicenter series of 197 patients with MF undergoing allo-HCT. After a median follow-up of 3.1 years, 47% of patients had died, and the estimated 5-year survival rate was 51%. Projected 5-year risk of nonrelapse mortality and relapse incidence was 30% and 20%, respectively. Factors independently associated with increased mortality were a hematopoietic cell transplantation-specific comorbidity index (HCT-CI) ≥3 and receiving a graft from an HLA-mismatched unrelated donor or cord blood, whereas post-transplant cyclophosphamide (PT-Cy) was associated with improved survival. Donor type was the only parameter included in the MTSS model with independent prognostic value for survival. According to the MTSS, 3-year survival was 62%, 66%, 37%, and 17% for low-, intermediate-, high-, and very high-risk groups, respectively. By pooling together the low- and intermediate-risk groups, as well as the high- and very high-risk groups, we pinpointed 2 categories: standard risk and high risk (25% of the series). Three-year survival was 62% in standard-risk and 25% in high-risk categories (P <.001). We derived a risk score based on the 3 independent risk factors for survival in our series (donor type, HCT-CI, and PT-Cy). The corresponding 5-year survival for the low-, intermediate-, and high-risk categories was 79%, 55%, and 32%, respectively (P <.001). In conclusion, the MTSS model failed to clearly delineate 4 prognostic groups in our series but may still be useful to identify a subset of patients with poor outcome. We provide a simple prognostic scoring system for risk/benefit considerations before transplantation in patients with MF

Uterine electromyography for discrimination of labor imminence in women with threatened preterm labor under tocolytic treatment

[EN] As one of the main aims of obstetrics is to be able to detect imminent delivery in patients with threatened preterm labor, the techniques currently used in clinical practice have serious limitations in this respect. The electrohysterogram (EHG) has now emerged as an alternative technique, providing relevant information about labor onset when recorded in controlled checkups without administration of tocolytic drugs. The studies published to date mainly focus on EHG-burst analysis and, to a lesser extent, on whole EHG window analysis. The study described here assessed the ability of EHG signals to discriminate imminent labor (The ability of EHG recordings to predict imminent labor (<7days) was analyzed in preterm threatened patients undergoing tocolytic therapies by means of EHG-burst and whole EHG window analysis. 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