A multichannel time–frequency and multi-wavelet toolbox for uterine electromyography processing and visualisation

Batista, Arnaldo; Najdi, Shirin; Godinho, Daniela M.; Martins, Catarina; Serrano, Fátima; Ortigueira, Manuel Duarte; Rato, Raul Tello

doi:10.1016/j.compbiomed.2016.07.003

Cited by 27 publications

(22 citation statements)

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“…It is hypothesized that FWL is related to the propagation of the EHG signal and FWH to the excitability of the uterine cells (Devedeux et al, 1993). Nonetheless, surface EHG amplitude is low (between tenths and hundredths of µV) and its recording is affected by interference, noise and artifacts, including: drift, maternal respiration, maternal ECG, fetal ECG, electromyography noise, power line interference and motion artifacts (Batista et al, 2016). As commented above, baseline drift frequency content can overlap that of the EHG short wave and is usually discarded.…”

Section: Signal Componentsmentioning

confidence: 99%

Electrohysterography in the diagnosis of preterm birth: a review

et al. 2018

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Section: Signal Componentsmentioning

confidence: 99%

Electrohysterography in the diagnosis of preterm birth: a review

et al. 2018

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“…Many methods to assess the danger of preterm birth use the frequency band 0.34-1.0 Hz of EHG signals [ 10 , 17 , 18 , 29 , 31 , 32 ]. This is done to avoid maternal respiration in the frequency band 0.2-0.34 Hz (assuming a respiratory rate from 12 to 20.4 breaths per min), and to avoid the influence of maternal electrocardiogram (ECG) in terms of maternal heart rate, a strong component, above 1.0 Hz (assuming a maternal heart rate of 60 beats per min [bpm] and higher) together with high frequency harmonics [ 37 ]. On the other hand, there is evidence that useful information regarding electrical activity of uterine bursts lies in the frequency band 0.1-4.7 Hz divided into two frequency bands: 0.1-1.2 Hz, Fast Wave Low (F W L ), and 1.2-4.7 Hz, Fast Wave High (F W H ) [ 11 , 38 ].…”

Section: Introductionmentioning

confidence: 99%

“…The ECG activity is of strong potential, about 1 mV, while the potential of EHG bursts is about 50 μV; the ratio is about 20. The influence of the maternal ECG [ 5 ], as well as the influence of the maternal heart rate with higher harmonics [ 37 ], on the uterine EHG activity are known. Besides, none of the studies were dedicated to frequency analysis of the external tocogram (TOCO signal) in the frequency band above 1.0 Hz where permanent maternal heart activity (maternal heart rate) in the mechanical sense, i.e., mechanical “vibrating” of the uterus due to the heart beating, is expected.…”

Section: Introductionmentioning

confidence: 99%

Characterization and automatic classification of preterm and term uterine records

2018

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Predicting preterm birth is uncertain, and numerous scientists are searching for non-invasive methods to improve its predictability. Current researches are based on the analysis of ElectroHysteroGram (EHG) records, which contain information about the electrophysiological properties of the uterine muscle and uterine contractions. Since pregnancy is a long process, we decided to also characterize, for the first time, non-contraction intervals (dummy intervals) of the uterine records, i.e., EHG signals accompanied by a simultaneously recorded external tocogram measuring mechanical uterine activity (TOCO signal). For this purpose, we developed a new set of uterine records, TPEHGT DS, containing preterm and term uterine records of pregnant women, and uterine records of non-pregnant women. We quantitatively characterized contraction intervals (contractions) and dummy intervals of the uterine records of the TPEHGT DS in terms of the normalized power spectra of the EHG and TOCO signals, and developed a new method for predicting preterm birth. The results on the characterization revealed that the peak amplitudes of the normalized power spectra of the EHG and TOCO signals of the contraction and dummy intervals in the frequency band 1.0-2.2 Hz, describing the electrical and mechanical activity of the uterus due to the maternal heart (maternal heart rate), are high only during term pregnancies, when the delivery is still far away; and they are low when the delivery is close. However, these peak amplitudes are also low during preterm pregnancies, when the delivery is still supposed to be far away (thus suggesting the danger of preterm birth); and they are also low or barely present for non-pregnant women. We propose the values of the peak amplitudes of the normalized power spectra due to the influence of the maternal heart, in an electro-mechanical sense, in the frequency band 1.0-2.2 Hz as a new biophysical marker for the preliminary, or early, assessment of the danger of preterm birth. The classification of preterm and term, contraction and dummy intervals of the TPEHGT DS, for the task of the automatic prediction of preterm birth, using sample entropy, the median frequency of the power spectra, and the peak amplitude of the normalized power spectra, revealed that the dummy intervals provide quite comparable and slightly higher classification performances than these features obtained from the contraction intervals. This result suggests a novel and simple clinical technique, not necessarily to seek contraction intervals but using the dummy intervals, for the early assessment of the danger of preterm birth. Using the publicly available TPEHG DB database to predict preterm birth in terms of classifying between preterm and term EHG records, the proposed method outperformed all currently existing methods. The achieved classification accuracy was 100% for early records, recorded around the 23rd week of pregnancy; and 96.33%, the area under the curve of 99.44%, for all records of the database. Since the proposed method is capable ...

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“…Considering term nonlabor uterine records of the TPEHGT DS, or term early EHG 792 records of the TPEHG DB, a strong activity in the frequency band B1 for the EHG 793 signals is present permanently and throughout the records (Figs 6 and S6 Fig) human organs that could be measured via EHG signals, was reported [37]. Another 799 aspect is the influence of the maternal heart on the uterus in the mechanical sense.…”

mentioning

confidence: 98%

“…769 30/50 Table 10 summarizes the classification performance results obtained for preterm and 770 term EHG records recorded early, and for all preterm and term EHG records of the 771 TPEHG DB. For early records, and cross-validation with five-and ten-folds, the The influence of the maternal ECG signal on the uterine EHG activity is known [5,37]. 783 In order to assess the intensity of the influence of the maternal ECG on the uterus in 784 the electrical sense, it is necessary to measure the maternal heart's influence within the 785 EHG signals.…”

mentioning

confidence: 99%

Characterization and automatic classification of preterm and term uterine records

Jager

Libenšek

Geršak

2018

Preprint

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Predicting preterm birth is uncertain, and numerous scientists are searching for non-invasive methods to improve its predictability. Current researches are based on the analysis of ElectroHysteroGram (EHG) records, which contain information about the electrophysiological properties of the uterine muscle and uterine contractions. Since pregnancy is a long process, we decided to also characterize, for the first time, non-contraction intervals (dummy intervals) of the uterine records, i.e., EHG signals accompanied by a simultaneously recorded external tocogram measuring mechanical uterine activity (TOCO signal). For this purpose, we developed a new set of uterine records, TPEHGT DS, containing preterm and term uterine records of pregnant women, and uterine records of non-pregnant women. We quantitatively characterized contraction intervals (contractions) and dummy intervals of the uterine records of the TPEHGT DS in terms of the normalized power spectra of the EHG and TOCO signals, and developed a new method for predicting preterm birth. The results on the characterization revealed that the peak amplitudes of the normalized power spectra of the EHG and TOCO signals of the contraction and dummy intervals in the frequency band 1.0-2.2 Hz, describing the electrical and mechanical activity of the uterus due to the maternal heart (maternal heart rate), are high only during term pregnancies, when the delivery is still far away; and they are low when the delivery is close. However, these peak amplitudes are also low during preterm pregnancies, when the delivery is still supposed to be far away (thus suggesting the danger of preterm birth); and they are also low or barely present for non-pregnant women. We propose the values of the peak amplitudes of the normalized power spectra due to the influence of the maternal heart, in an electro-mechanical sense, in the frequency band 1.0-2.2 Hz as a new biophysical marker for the preliminary, or early, assessment of the danger of preterm birth. The classification of preterm and term, contraction and dummy intervals of the TPEHGT DS, for the task of the automatic prediction of preterm birth, using sample entropy, the median frequency of the power spectra, and the peak amplitude of the normalized power spectra, revealed that the dummy intervals provide quite comparable and slightly higher classification performances than these features obtained from the contraction intervals. This result suggests a novel and simple clinical technique, not necessarily to seek contraction intervals but using the dummy intervals, for the early assessment of the danger of preterm birth. Using the publicly available TPEHG DB database to predict preterm birth in terms of classifying between preterm and term EHG records, the 1/50 proposed method outperformed all currently existing methods. The achieved classification accuracy was 100% for early records, recorded around the 23rd week of pregnancy; and 96.33%, the area under the curve of 99.44%, for all records of the database. Since the proposed method is cap...

show abstract

A multichannel time–frequency and multi-wavelet toolbox for uterine electromyography processing and visualisation

Cited by 27 publications

References 57 publications

Electrohysterography in the diagnosis of preterm birth: a review

Electrohysterography in the diagnosis of preterm birth: a review

Characterization and automatic classification of preterm and term uterine records

Characterization and automatic classification of preterm and term uterine records

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