Fetal source extraction from magnetocardiographic recordings by dependent component analysis

Araújo, Dráulio Barros de; Barros, Allan Kardec; Estombelo-Montesco, Carlos A.; Zhao, Hui; Roque, Antônio C.; Baffa, Oswaldo; Wakai, Ronald T.; Ohnishi, Noboru

doi:10.1088/0031-9155/50/19/002

Cited by 10 publications

(6 citation statements)

References 23 publications

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“…The multivariate data were presented to an Infomax ICA algorithm implemented in EEGLAB toolbox (Delorme and Makeig 2004), in order to segregate the contributions from spatially distinct electrophysiological sources. ICA was proved to be highly efficient for artifact rejection in biomedical signal applications (Jung et al 2000) and, in particular, in multichannel fetal magnetographic recordings (Mantini et al 2006, de Araujo et al 2005, Comani et al 2004. The algorithm is based on the maximum entropy method developed by Bell and Sejnowski (1995), with the natural gradient feature introduced by Amari et al (1996).…”

Section: Discussionmentioning

confidence: 99%

Magnetographic assessment of fetal hiccups and their effect on fetal heart rhythm

Popescu¹,

Popescu²,

Bennett³

et al. 2007

Physiol. Meas.

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Fetal hiccups emerge as early as nine weeks post-conception, being the predominant diaphragmatic movement before 26 weeks of gestation. They are considered as a programmed isometric inspiratory muscle exercise of the fetus in preparation for the post-natal respiratory function, or a manifestation of a reflex circuitry underlying the development of suckling and gasping patterns. The present paper provides the first evidence of non-invasive biomagnetic measurements of the diaphragm spasmodic contractions associated with fetal hiccups. The magnetic field patterns generated by fetal hiccups exhibit well-defined morphological features, consisting of an initial high frequency transient waveform followed by a more prolonged low frequency component. This pattern is consistent across recordings obtained from two fetal subjects, and it is confirmed by signals recorded in a neonatal subject. These results demonstrate that fetal biomagnetometry can provide insights into the electrophysiological mechanisms of diaphragm motor function in the fetus. Additionally, we study the correlation between hiccup events and fetal cardiac rhythm and provide evidence that hiccups may modulate the fetal heart rate during the last trimester of pregnancy.

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Section: Discussionmentioning

confidence: 99%

Magnetographic assessment of fetal hiccups and their effect on fetal heart rhythm

Popescu¹,

Popescu²,

Bennett³

et al. 2007

Physiol. Meas.

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“…In this context, it has been proposed as an alternative method using the Shannon entropy (de Araujo et al 2003), which assumes no shape for the HRF but instead only considers the general structure of the signal, which presents maximum amplitude in the first part of ER response. Recently, there has been an increasing interest in applying the Tsallis non-extensive entropy (Tsallis 1988) to the neuroscience scenario (Tedeschi et al 2004, 2005, Mazza et al 2002Cabella et al 2008Cabella et al , 2009. In particular, Tedeschi et al (2005) developed an fMRI method by applying the Tsallis entropy, which differs considerably from that presented in this work.…”

Section: Introductionmentioning

confidence: 88%

“…A few emerging methods do not rely on such assumption, as independent component analysis (ICA) (Mckeown et al 1998, de Araujo et al 2005 and the analysis of variance (ANOVA) (Clare et al 1999).…”

Section: Introductionmentioning

confidence: 99%

Non-extensive entropy and the extraction of BOLD spatial information in event-related functional MRI

Sturzbecher¹,

Tedeschi²,

Cabella³

et al. 2008

Phys. Med. Biol.

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Functional magnetic resonance imaging (fMRI) data analysis has been carried out recently in the framework of information theory, by means of the Shannon entropy. As a natural extension, a method based on the generalized Tsallis entropy was developed to the analysis event-related (ER-fMRI), where a brief stimulus is presented, followed by a long period of rest. The new technique aims for spatial localization neuronal activity due to a specific task. This method does not require a priori hypothesis of the hemodynamic response function (HRF) shape and the linear relation between BOLD responses with the presented task. Numerical simulations were performed so as to determine the optimal values of the Tsallis q parameter and the number of levels, L. In order to avoid undesirable divergences of the Tsallis entropy, only positive q values were studied. Results from simulated data (with L = 3) indicated that, for q = 0.8, the active brain areas are detected with the highest performance. Moreover, the method was tested for an in vivo experiment and demonstrated the ability to discriminate active brain regions that selectively responded to a bilateral motor task.

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“…Techniques utilizing a multi-channel signal source include multiple and single-source methods. Single-channel signal source methods are based on for example Wavelet Transform (WT), Karvounis et al ( 2004 ), Datian and Xuemei ( 1996 ), Hassanpour and Parsaei ( 2007 ), Bsoul ( 2015 ), Ivanushkina et al ( 2014 ), Abburi and Chandrasekhara Sastry ( 2012 ), Bensafia et al ( 2017 ), Castillo et al ( 2013 ), Correlation Techniques De Araujo et al ( 2005 ), Averaging Techniques (AT) Hon and Lee ( 1963 ), Hon and Lee ( 1964 ), Template Subtraction Tsui et al ( 2017 ), Singular Value Decomposition (SVD) Kanjilal et al ( 1997 ), Adaptive Noise Canceler (ANC) Zhang et al ( 2017 ), and so on.…”

Section: State Of the Artmentioning

confidence: 99%

Comparative Effectiveness of ICA and PCA in Extraction of Fetal ECG From Abdominal Signals: Toward Non-invasive Fetal Monitoring

et al. 2018

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Non-adaptive signal processing methods have been successfully applied to extract fetal electrocardiograms (fECGs) from maternal abdominal electrocardiograms (aECGs); and initial tests to evaluate the efficacy of these methods have been carried out by using synthetic data. Nevertheless, performance evaluation of such methods using real data is a much more challenging task and has neither been fully undertaken nor reported in the literature. Therefore, in this investigation, we aimed to compare the effectiveness of two popular non-adaptive methods (the ICA and PCA) to explore the non-invasive (NI) extraction (separation) of fECGs, also known as NI-fECGs from aECGs. The performance of these well-known methods was enhanced by an adaptive algorithm, compensating amplitude difference and time shift between the estimated components. We used real signals compiled in 12 recordings (real01–real12). Five of the recordings were from the publicly available database (PhysioNet-Abdominal and Direct Fetal Electrocardiogram Database), which included data recorded by multiple abdominal electrodes. Seven more recordings were acquired by measurements performed at the Institute of Medical Technology and Equipment, Zabrze, Poland. Therefore, in total we used 60 min of data (i.e., around 88,000 R waves) for our experiments. This dataset covers different gestational ages, fetal positions, fetal positions, maternal body mass indices (BMI), etc. Such a unique heterogeneous dataset of sufficient length combining continuous Fetal Scalp Electrode (FSE) acquired and abdominal ECG recordings allows for robust testing of the applied ICA and PCA methods. The performance of these signal separation methods was then comprehensively evaluated by comparing the fetal Heart Rate (fHR) values determined from the extracted fECGs with those calculated from the fECG signals recorded directly by means of a reference FSE. Additionally, we tested the possibility of non-invasive ST analysis (NI-STAN) by determining the T/QRS ratio. Our results demonstrated that even though these advanced signal processing methods are suitable for the non-invasive estimation and monitoring of the fHR information from maternal aECG signals, their utility for further morphological analysis of the extracted fECG signals remains questionable and warrants further work.

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Fetal source extraction from magnetocardiographic recordings by dependent component analysis

Cited by 10 publications

References 23 publications

Magnetographic assessment of fetal hiccups and their effect on fetal heart rhythm

Magnetographic assessment of fetal hiccups and their effect on fetal heart rhythm

Non-extensive entropy and the extraction of BOLD spatial information in event-related functional MRI

Comparative Effectiveness of ICA and PCA in Extraction of Fetal ECG From Abdominal Signals: Toward Non-invasive Fetal Monitoring

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