Optimization of adaptive filter control parameters for non-invasive fetal electrocardiogram extraction

Radana Kahankova; Martina Mikolasova; Radek Martinek

doi:10.1371/journal.pone.0266807

Peer Review History

Original SubmissionJuly 26, 2021
14 Feb 2022 Decision Letter - Ardashir Mohammadzadeh, Editor PONE-D-21-24207Optimization of Adaptive Filter Control Parameters for Non-Invasive Fetal Electrocardiogram ExtractionPLOS ONE Dear Dr. Kahankova, Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. Please submit your revised manuscript by Mar 31 2022 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file. 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The PLOS ONE style templates can be found at https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf 2. Thank you for stating the following financial disclosure: "R.M. and R.J. European Regional Development Fund in the Research Centre of Advanced Mechatronic Systems project through the Operational Programme Research, Development and Education under Project CZ.02.1.01/0.0/0.0/16_019/0000867 M.M. Ministry of Education of the Czech Republic under Project SP2021/32." Please state what role the funders took in the study. If the funders had no role, please state: "The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript." If this statement is not correct you must amend it as needed. Please include this amended Role of Funder statement in your cover letter; we will change the online submission form on your behalf. 3. Please ensure that you refer to Figure 9 in your text as, if accepted, production will need this reference to link the reader to the figure. 4. We note you have included a table to which you do not refer in the text of your manuscript. Please ensure that you refer to Tables 1, 2, 3, 4, and 5 in your text; if accepted, production will need this reference to link the reader to the Table. 5. Please include captions for your Supporting Information files at the end of your manuscript, and update any in-text citations to match accordingly. Please see our Supporting Information guidelines for more information: http://journals.plos.org/plosone/s/supporting-information. [Note: HTML markup is below. Please do not edit.] Reviewers' comments: Reviewer's Responses to Questions Comments to the Author 1. Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. Reviewer #1: Yes Reviewer #2: Yes ******** 2. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: Yes Reviewer #2: Yes ****** 3. Have the authors made all data underlying the findings in their manuscript fully available? The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified. Reviewer #1: Yes Reviewer #2: Yes ****** 4. Is the manuscript presented in an intelligible fashion and written in standard English? PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here. Reviewer #1: Yes Reviewer #2: Yes ****** 5. Review Comments to the Author Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters) Reviewer #1: This paper is focused on the design, implementation and verification of a novel method for the optimization of the control parameters of different hybrid systems used for non-invasive fetal electrocardiogram (fECG) extraction. This paper is generally well written with sufficient analysis. It can be accepted if the following concerns can be addressed. 1. Please ensure all the variables have been defined clearly in the paper. 2. The parameter tuning is critical to the performance of the discussed method, so more details should be given on how to select the parameters. 3. Least squares-based methods such as RLS and LMS have been widely used for system parameter identification, e.g., DOI: 10.1109/JESTPE.2021.3098836; DOI: 10.1109/TTE.2020.2994543. Such works can be included for brief discussion. 4. Least squares-based identification is vulnerable to the noises on system input. Noise-compensated versions of them have been proposed in the literature for noise-immune and unbiased identification, e.g., DOI: 10.1109/TIE.2019.2962429; DOI: 10.1109/TIE.2021.3063968. Such works can be mentioned for completeness and maybe as a future work. 5. The conclusions can be further improved. Primary findings with statistical results should be given. Reviewer #2: This article raises a very interesting topic and will definitely be discussed further in the future. And after applying a minor change can be published 1- More literature needs to be surveyed. 2- Discussion is short. Please express it more detailed. ****** 6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files. If you choose “no”, your identity will remain anonymous but your review may still be made public. Do you want your identity to be public for this peer review?** For information about this choice, including consent withdrawal, please see our Privacy Policy. Reviewer #1: No Reviewer #2: No [NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.] While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step. https://doi.org/10.1371/journal.pone.0266807.r001
Revision 1
21 Feb 2022 Author Response Responses to Editor: Comment 1. Please ensure that you refer to Figure 9 in your text as, if accepted, production will need this reference to link the reader to the figure. Authors’ action: We added reference to Fig. 6 (lines 279, 294) and Fig. 9 (line 417). Comment 2. We note you have included a table to which you do not refer in the text of your manuscript. Please ensure that you refer to Tables 1, 2, 3, 4, and 5 in your text; if accepted, production will need this reference to link the reader to the Table. Authors’ action: We went through the manuscript, all tables are mentioned: Tab1 (lines 102 and 117), Tab2 (line 278), Tab 3 (lines 326, 328, 338, 345), Tab4 (line 363), Tab5 (lines 431, 434, 438, 474) Reviewer #1 This paper is focused on the design, implementation and verification of a novel method for the optimization of the control parameters of different hybrid systems used for non-invasive fetal electrocardiogram (fECG) extraction. This paper is generally well written with sufficient analysis. It can be accepted if the following concerns can be addressed. Comment 1: Please ensure all the variables have been defined clearly in the paper. Authors’ answer: Thank you, for your suggestion. We went through the text and corrected parts where the variables were not sufficiently described. Authors’ action: We found the cases where the variables were not sufficiently defined and corrected them. Comment 2: The parameter tuning is critical to the performance of the discussed method, so more details should be given on how to select the parameters. Authors’ answer: Thank you, for your suggestion, this will be added. Authors’ action: We added more details regarding selection of the parameters to be tuned. Comment 3: Least squares-based methods such as RLS and LMS have been widely used for system parameter identification, e.g., DOI: 10.1109/JESTPE.2021.3098836; DOI: 10.1109/TTE.2020.2994543. Such works can be included for brief discussion. Authors’ answer: Thank you, for your suggestion. We mentioned system parameter identification as one of the use cases of LMS algorithms. The works are from quite different area not related to biosignals, so we did not make extended discussion of them. Authors’ action: We mentioned system parameter identification as one of the use cases of LMS algorithms (line 133). We included the mentioned works as references. Comment 4: Least squares-based identification is vulnerable to the noises on system input. Noise-compensated versions of them have been proposed in the literature for noise-immune and unbiased identification, e.g., DOI: 10.1109/TIE.2019.2962429; DOI: 10.1109/TIE.2021.3063968. Such works can be mentioned for completeness and maybe as a future work. Authors’ answer: Thank you, for your suggestion. We mentioned this in the introduction but since the mentioned works and the approach is from a completely different field that is not related to proposed study, we did not include it into the future work in further discussions. Authors’ action: We added this information and reference to the introduction. Comment 5: The conclusions can be further improved. Primary findings with statistical results should be given. Authors’ answer: Thank you, for your suggestion. Indeed, the conclusion was not sufficient. Authors’ action: We expanded the conclusion section. Reviewer #2 This article raises a very interesting topic and will definitely be discussed further in the future. And after applying a minor change can be published Comment 1: More literature needs to be surveyed. Authors’ answer: Thank you, for your suggestion, we extended the literature survey for the latest research outcomes and added them to the introduction and comparison of the results. Authors’ action: The literature survey was extended. Comment 2: Discussion is short. Please express it more detailed. Authors’ answer: Thank you, for your suggestion, the discussion was not structured right and seemed short. Authors’ action: We revised the discussion section. Attachments Attachment Submitted filename: Response to Reviewers.pdf https://doi.org/10.1371/journal.pone.0266807.r002
21 Mar 2022 Decision Letter - Ardashir Mohammadzadeh, Editor PONE-D-21-24207R1Optimization of Adaptive Filter Control Parameters for Non-Invasive Fetal Electrocardiogram ExtractionPLOS ONE Dear Dr. Kahankova, Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. Please submit your revised manuscript by May 05 2022 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file. Please include the following items when submitting your revised manuscript: A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'. A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'. An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'. If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter. If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols. We look forward to receiving your revised manuscript. Kind regards, Ardashir Mohammadzadeh, Phd Academic Editor PLOS ONE Journal Requirements: Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice. Additional Editor Comments: One of the reviewers has some concern about the novelties of paper; please revise the paper according the comments. [Note: HTML markup is below. Please do not edit.] Reviewers' comments: Reviewer's Responses to Questions Comments to the Author 1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation. Reviewer #2: All comments have been addressed ******** 2. Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. Reviewer #2: Yes ****** 3. Has the statistical analysis been performed appropriately and rigorously? Reviewer #2: Yes ****** 4. Have the authors made all data underlying the findings in their manuscript fully available? The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified. Reviewer #2: Yes ****** 5. Is the manuscript presented in an intelligible fashion and written in standard English? PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here. Reviewer #2: Yes ****** 6. Review Comments to the Author Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters) Reviewer #2: What is the difference between your work and the method presented in the following article? Katerina Barnova, Radek Martinek, Rene Jaros, Radana Kahankova, Khosrow Behbehani, Vaclav Snasel, System for adaptive extraction of non-invasive fetal electrocardiogram, Applied Soft Computing, Volume 113, Part B, 2021, 107940, ISSN 1568-4946, https://doi.org/10.1016/j.asoc.2021.107940. ****** 7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files. If you choose “no”, your identity will remain anonymous but your review may still be made public. Do you want your identity to be public for this peer review?** For information about this choice, including consent withdrawal, please see our Privacy Policy. Reviewer #2: No [NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.] While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step. https://doi.org/10.1371/journal.pone.0266807.r003
Revision 2
27 Mar 2022 Author Response Responses to Editor: Comment 1. One of the reviewers has some concern about the novelties of paper; please revise the paper according the comments. Authors’ action: We revised the paper according the comments. Reviewer #2: What is the difference between your work and the method presented in the following article? Katerina Barnova et al. System for adaptive extraction of non-invasive fetal electrocardiogram, Applied Soft Computing, Volume 113, Part B, 2021, 107940, ISSN 1568-4946, https://doi.org/10.1016/j.asoc.2021.107940. Authors’ answer: In the proposed work, we tested and optimized in total of 5 algorithms in hybrid fECG extraction system: ADALINE, LMS, SE-LMS, RLS and FTF. The combinations of ICA-ADALINE and ICA-SELMS and have not been used in the literature before. In the paper of Barnova you mentioned, the focus is fully on the ICA-FTF-CEEMDA extraction system. However, in our results, the FTF algorithm is achieving poorest results when used alone, i.e. without final processing using CEEMDA (method who’s settings also need to be optimized). In our paper, the ADALINE method is most powerful when used alone. Therefore, it could be further improved when additional processing enhancing the fetal R peaks was used (such as CEEMDA method). Further, Barnova in her paper admits that the limitation of her work is the need for optimal parameter setting of both FTF and CEEMDA algorithms (see table 8 summary in her paper). Contrary to paper of Barnova et al., we did not focus only on one method but on finding a way to optimize them all so they function well even without additional postprocessing methods – i.e. optimizing them for fECG extraction (as stated in the title of the article). Authors’ action: We added the information regarding this paper to the manuscript and highlighted the limitations. Attachments Attachment Submitted filename: Response to Reviewers2.pdf https://doi.org/10.1371/journal.pone.0266807.r004
29 Mar 2022 Decision Letter - Ardashir Mohammadzadeh, Editor Optimization of Adaptive Filter Control Parameters for Non-Invasive Fetal Electrocardiogram Extraction PONE-D-21-24207R2 Dear Dr. Kahankova, We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements. Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication. An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org. If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org. Kind regards, Ardashir Mohammadzadeh, Phd Academic Editor PLOS ONE Additional Editor Comments (optional): Reviewers' comments: https://doi.org/10.1371/journal.pone.0266807.r005
Formally Accepted
1 Apr 2022 Acceptance Letter - Ardashir Mohammadzadeh, Editor PONE-D-21-24207R2 Optimization of Adaptive Filter Control Parameters for Non-Invasive Fetal Electrocardiogram Extraction Dear Dr. Kahankova: I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department. If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org. If we can help with anything else, please email us at plosone@plos.org. Thank you for submitting your work to PLOS ONE and supporting open access. Kind regards, PLOS ONE Editorial Office Staff on behalf of Dr. Ardashir Mohammadzadeh Academic Editor PLOS ONE https://doi.org/10.1371/journal.pone.0266807.r006

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