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Pirnar Ž, Jager F, Geršak K. Characterization and separation of preterm and term spontaneous, induced, and cesarean EHG records. Comput Biol Med 2022; 151:106238. [PMID: 36343404 DOI: 10.1016/j.compbiomed.2022.106238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 09/30/2022] [Accepted: 10/22/2022] [Indexed: 12/27/2022]
Abstract
To improve the understanding of the underlying physiological processes that lead to preterm birth, and different term delivery modes, we quantitatively characterized and assessed the separability of the sets of early (23rd week) and later (31st week) recorded, preterm and term spontaneous, induced, cesarean, and induced-cesarean electrohysterogram (EHG) records using several of the most widely used non-linear features extracted from the EHG signals. Linearly modeled temporal trends of the means of the median frequencies (MFs), and of the means of the peak amplitudes (PAs) of the normalized power spectra of the EHG signals, along pregnancy (from early to later recorded records), derived from a variety of frequency bands, revealed that for the preterm group of records, in comparison to all other term delivery groups, the frequency spectrum of the frequency band B0L (0.08-0.3 Hz) shifts toward higher frequencies, and that the spectrum of the newly identified frequency band B0L' (0.125-0.575 Hz), which approximately matches the Fast Wave Low band, becomes stronger. The most promising features to separate between the later preterm group and all other later term delivery groups appear to be MF (p=1.1⋅10-5) in the band B0L of the horizontal signal S3, and PA (p=2.4⋅10-8) in the band B0L' (S3). Moreover, the PA in the band B0L' (S3) showed the highest power to individually separate between the later preterm group and any other later term delivery group. Furthermore, the results suggest that in preterm pregnancies the resting maternal heart rate decreases between the 23rd and 31st week of gestation.
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Affiliation(s)
- Žiga Pirnar
- Faculty of Computer and Information Science, University of Ljubljana, Večna pot 113, 1000 Ljubljana, Slovenia
| | - Franc Jager
- Faculty of Computer and Information Science, University of Ljubljana, Večna pot 113, 1000 Ljubljana, Slovenia.
| | - Ksenija Geršak
- Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia; University Medical Center Ljubljana, Zaloška cesta 2, 1000 Ljubljana, Slovenia
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Martins D, Batista A, Mouriño H, Russo S, Esgalhado F, dos Reis CRP, Serrano F, Ortigueira M. Adaptive Filtering for the Maternal Respiration Signal Attenuation in the Uterine Electromyogram. SENSORS (BASEL, SWITZERLAND) 2022; 22:7638. [PMID: 36236736 PMCID: PMC9571637 DOI: 10.3390/s22197638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 10/05/2022] [Accepted: 10/06/2022] [Indexed: 06/16/2023]
Abstract
The electrohysterogram (EHG) is the uterine muscle electromyogram recorded at the abdominal surface of pregnant or non-pregnant woman. The maternal respiration electromyographic signal (MR-EMG) is one of the most relevant interferences present in an EHG. Alvarez (Alv) waves are components of the EHG that have been indicated as having the potential for preterm and term birth prediction. The MR-EMG component in the EHG represents an issue, regarding Alv wave application for pregnancy monitoring, for instance, in preterm birth prediction, a subject of great research interest. Therefore, the Alv waves denoising method should be designed to include the interference MR-EMG attenuation, without compromising the original waves. Adaptive filter properties make them suitable for this task. However, selecting the optimal adaptive filter and its parameters is an important task for the success of the filtering operation. In this work, an algorithm is presented for the automatic adaptive filter and parameter selection using synthetic data. The filter selection pool comprised sixteen candidates, from which, the Wiener, recursive least squares (RLS), householder recursive least squares (HRLS), and QR-decomposition recursive least squares (QRD-RLS) were the best performers. The optimized parameters were L = 2 (filter length) for all of them and λ = 1 (forgetting factor) for the last three. The developed optimization algorithm may be of interest to other applications. The optimized filters were applied to real data. The result was the attenuation of the MR-EMG in Alv waves power. For the Wiener filter, power reductions for quartile 1, median, and quartile 3 were found to be -16.74%, -20.32%, and -15.78%, respectively (p-value = 1.31 × 10-12).
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Affiliation(s)
- Daniela Martins
- NOVA School of Science and Technology, NOVA University Lisbon, 2829-516 Caparica, Portugal
| | - Arnaldo Batista
- NOVA School of Science and Technology, NOVA University Lisbon, 2829-516 Caparica, Portugal
- UNINOVA-CTS, NOVA School of Science and Technology, NOVA University Lisbon, 2829-516 Caparica, Portugal
| | - Helena Mouriño
- Faculty of Sciences, Lisbon University, Campo Grande, 1749-016 Lisbon, Portugal
- CEAUL Faculty of Sciences, Lisbon University, Campo Grande, 1749-016 Lisbon, Portugal
| | - Sara Russo
- NOVA School of Science and Technology, NOVA University Lisbon, 2829-516 Caparica, Portugal
| | - Filipa Esgalhado
- NOVA School of Science and Technology, NOVA University Lisbon, 2829-516 Caparica, Portugal
| | - Catarina R. Palma dos Reis
- Department of Obstetrics, University Central Hospital Lisbon (CHULC), 1169-050 Lisboa, Portugal
- Comprehensive Health Research Centre (CHRC), NOVA Medical School, Universidade NOVA de Lisboa, 1169-056 Lisboa, Portugal
| | - Fátima Serrano
- Department of Obstetrics, University Central Hospital Lisbon (CHULC), 1169-050 Lisboa, Portugal
- Comprehensive Health Research Centre (CHRC), NOVA Medical School, Universidade NOVA de Lisboa, 1169-056 Lisboa, Portugal
| | - Manuel Ortigueira
- NOVA School of Science and Technology, NOVA University Lisbon, 2829-516 Caparica, Portugal
- UNINOVA-CTS, NOVA School of Science and Technology, NOVA University Lisbon, 2829-516 Caparica, Portugal
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Şan M, Batista A, Russo S, Esgalhado F, dos Reis CRP, Serrano F, Ortigueira M. A Preliminary Exploration of the Placental Position Influence on Uterine Electromyography Using Fractional Modelling. SENSORS 2022; 22:s22051704. [PMID: 35270857 PMCID: PMC8914849 DOI: 10.3390/s22051704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 01/25/2022] [Accepted: 02/18/2022] [Indexed: 02/04/2023]
Abstract
The uterine electromyogram, also called electrohysterogram (EHG), is the electrical signal generated by uterine contractile activity. The EHG has been considered an expanding technique for pregnancy monitoring and preterm risk evaluation. Data were collected on the abdominal surface. It has been speculated the effect of the placenta location on the characteristics of the EHG. In this work, a preliminary exploration method is proposed using the average spectra of Alvarez waves contractions of subjects with anterior and non-anterior placental position as a basis for the triple-dispersion Cole model that provides a best fit for these two cases. This leads to the uterine impedance estimation for these two study cases. Non-linear least square fitting (NLSF) was applied for this modelling process, which produces electric circuit fractional models’ representations. A triple-dispersion Cole-impedance model was used to obtain the uterine impedance curve in a frequency band between 0.1 and 1 Hz. A proposal for the interpretation relating the model parameters and the placental influence on the myometrial contractile action is provided. This is the first report regarding in silico estimation of the uterine impedance for cases involving anterior or non-anterior placental positions.
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Affiliation(s)
- Müfit Şan
- Department of Mathematics, Çankırı Karatekin University, Çankırı 18100, Turkey;
| | - Arnaldo Batista
- NOVA School of Science and Technology, NOVA University Lisbon, 2829-516 Caparica, Portugal; (S.R.); (F.E.); (M.O.)
- UNINOVA-CTS, NOVA School of Science and Technology, NOVA University Lisbon, 2829-516 Lisbon, Portugal
- Correspondence:
| | - Sara Russo
- NOVA School of Science and Technology, NOVA University Lisbon, 2829-516 Caparica, Portugal; (S.R.); (F.E.); (M.O.)
| | - Filipa Esgalhado
- NOVA School of Science and Technology, NOVA University Lisbon, 2829-516 Caparica, Portugal; (S.R.); (F.E.); (M.O.)
- NMT S.A., Parque Tecnológico de Cantanhede, Núcleo 04, Lote 3, 3060-197 Lisbon, Portugal
| | - Catarina R. Palma dos Reis
- Maternidade Alfredo da Costa, Rua Viriato 1, 1050-170 Lisbon, Portugal; (C.R.P.d.R.); (F.S.)
- Faculty of Medical Sciences, Nova Medical School, NOVA University Lisbon, 1169-056 Lisbon, Portugal
| | - Fátima Serrano
- Maternidade Alfredo da Costa, Rua Viriato 1, 1050-170 Lisbon, Portugal; (C.R.P.d.R.); (F.S.)
- Faculty of Medical Sciences, Nova Medical School, NOVA University Lisbon, 1169-056 Lisbon, Portugal
| | - Manuel Ortigueira
- NOVA School of Science and Technology, NOVA University Lisbon, 2829-516 Caparica, Portugal; (S.R.); (F.E.); (M.O.)
- UNINOVA-CTS, NOVA School of Science and Technology, NOVA University Lisbon, 2829-516 Lisbon, Portugal
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Abstract
The current issue (volume 13 issue 6, 2021) is a Special Issue jointly dedicated to scientific content presented at the 20th triennial IUPAB Congress that was held in conjunction with both the 45th Annual Meeting of the Brazilian Biophysical Society (Sociedade Brasileira de Biofísica - SBBf) and the 50th Annual Meeting of the Brazilian Society for Biochemistry and Molecular Biology (Sociedade Brasileira de Bioquímica e Biologia Molecular - SBBq). In addition to describing the scientific and nonscientific content arising from the meeting this sub-editorial also provides a look back at some of the high points for Biophysical Reviews in the year 2021 before going on to describe a number of matters of interest to readers of the journal in relation to the coming year of 2022.
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Affiliation(s)
- Damien Hall
- WPI Nano Life Science Institute, Kanazawa University, Kakumamachi, Kanazawa, Ishikawa 920-1164 Japan
- Department of Applied Physics, Aalto University, FI-00076 Aalto, Finland
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Hall D. Biophysical reviews-providing an effective critique. Biophys Rev 2021; 13:427-434. [PMID: 34471433 PMCID: PMC8355284 DOI: 10.1007/s12551-021-00824-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 07/19/2021] [Indexed: 12/11/2022] Open
Abstract
This Editorial for Volume 13, Issue 4 of Biophysical Reviews begins with an introduction to the invited Review contributed by the 2021 winner of "The Michèle Auger Award for Young Scientists' Independent Research" (Assoc. Prof. Jorge Alegre-Cebollada). After providing a short summary of the other articles contained within the Issue, we discuss some additional matters important to the journal and its readers. In particular, this Editorial describes ongoing preparations for the upcoming IUPAB World Congress (October 4th-8th); it introduces two new Executive Editors from the UK and Spain; it describes the journal's placement in the latest SCIMago journal rankings, and it explains a new feature of the journal-"The Biophysical Reviews Historical Top Five". This piece closes with some thoughts about what might constitute a constructive critique of a manuscript.
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Affiliation(s)
- Damien Hall
- WPI Nano Life Science Institute, Kanazawa University, Kakumamachi, Kanazawa, Ishikawa 920-1164 Japan
- Department of Applied Physics, Aalto University, FI-00076 Aalto, Finland
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