Gait stability in ambulant children with cerebral palsy during dual tasks

Sophie Wist; Lena Carcreff; Sjoerd M. Bruijn; Gilles Allali; Christopher J. Newman; Joel Fluss; Stéphane Armand

doi:10.1371/journal.pone.0270145

Peer Review History

Original SubmissionMarch 1, 2022
26 Apr 2022 Decision Letter - Yury Ivanenko, Editor PONE-D-22-05897Gait stability in ambulant children with cerebral palsy during dual tasksPLOS ONE Dear Dr. Wist, 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. While the reviewer is generally positive about the study, based on his/her and my own assessment of the ms, some adjustments and clarifications in the methods/results are necessary (see the comments). Please submit your revised manuscript by Jun 04 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. 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Sjoerd M.Bruijn was funded by a VIDI grant (016.Vidi.178.014) from the Dutch Organization for Scientific Research (NWO)." We note that you have provided funding information. However, funding information should not appear in the Acknowledgments section or other areas of your manuscript. We will only publish funding information present in the Funding Statement section of the online submission form. Please remove any funding-related text from the manuscript and let us know how you would like to update your Funding Statement. Currently, your Funding Statement reads as follows: "This work was supported by La Fondation Paralysie Cerebrale (Paris, France,https://www.fondationparalysiecerebrale.org/), no grant number is available. Sjoerd M.Bruijn was funded by a VIDI grant (016.Vidi.178.014) from the Dutch Organization for Scientific Research (NWO, https://www.nwo.nl/en). 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We will update your Data Availability statement to reflect the information you provide in your cover letter. 5. 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 If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references.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. [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 ******** 2. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: 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. 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(Please upload your review as an attachment if it exceeds 20,000 characters) Reviewer #1: Review of Manuscript ID PONE-D-22-05897 ’Gait stability in ambulant children with cerebral palsy during dual tasks’. This is an excellent study of an important topic. I have some suggestions to improve clarity outlined below. METHOD • I recommend you change the description of the study design (line 13, 81). Currently it reads: ’prospective cross-sectional study with matched controls.’ These are three different designs: prospective implies that it would be a longitudinal cohort study, cross-sectional that it reflects one time point for each individual (cannot be prospective or retrospective), and finally, matched controls that it would be some sort of a case control study. In the statistical section (line 185-6) you refer to the used of the STROBE checklist for case control studies. So, I suggest you choose one of them rather than all three. • According to the method section (line 86-9) children with CP were matched to controls based on age: ’…as well as age matched children with TD. The sample consisted of two groups, children with CP (CP group) and age-matched children with TD (TD group). Children were age matched with peers, with a range of ±1.5 years.’ However, in the discussion, limitations (line 296-7) you state they were matched by age and sex: ’We reduced the induced gait and cognitive differences by matching the patients per age and sex.’ Please revise for consistency. • Participants. Dysarthria with difficulties coordinating the muscles used for speaking and coordination of breathing, is more frequent in children with CP. This could potentially influence the tests (cognitive tasks requiring talk: numbers, fruits, animals and be worse while walking rapidly). If none of the children had dysarthria this might be worth mentioning in the method section. If not, it could be mentioned as a limitation. RESULTS • Table 1. According to the characteristics of the participants, the height and especially the mean weight of the study group (CP) exceeds the values of the control group (TD) by 10 kg. This is quite unusual, and typically we see the reversed pattern with more underweight in children with CP than in TP children. Currently the weight range is reported as 21 to 107 kg in the children with CP and that is unusually high. Are these values correct? If so, please highlight also in the discussion. • Table 3, it is interesting that children with CP seem to have the same cadence as TD children during all three conditions, even though step length is slightly shorter. I think this could be mentioned in the discussion. • Figures. Page 6 (line 202) you refer to Figure 1A and 2B for gait stability AP and ML directions. I think this should be Figure 2A and 2B. Figure 1 illustrating Foot Placement Estimator Values is presented at page 4. ****** 6. 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Revision 1
2 Jun 2022 Author Response Dear reviewer, Dear editorial board member, We would like to thank you for the positive feedback, and for giving us the chance to revise our work to improve its understandability and readability. We took all the comments into account and made the appropriate changes in the text with the ‘track changes’ mode. The details of the reviewer comments are available below. Reviewer #1 (Remarks to the Author): This is an excellent study of an important topic. I have some suggestions to improve clarity outlined below. METHOD • I recommend you change the description of the study design (line 13, 81). Currently it reads: ’prospective cross-sectional study with matched controls.’ These are three different designs: prospective implies that it would be a longitudinal cohort study, cross-sectional that it reflects one time point for each individual (cannot be prospective or retrospective), and finally, matched controls that it would be some sort of a case control study. In the statistical section (line 185-6) you refer to the used of the STROBE checklist for case control studies. So, I suggest you choose one of them rather than all three. Thank you for this recommendation. For more clarity we adapted the text, and the study design is now expressed as “cross-sectional study”. • According to the method section (line 86-9) children with CP were matched to controls based on age: ’…as well as age matched children with TD. The sample consisted of two groups, children with CP (CP group) and age-matched children with TD (TD group). Children were age matched with peers, with a range of ±1.5 years.’ However, in the discussion, limitations (line 296-7) you state they were matched by age and sex: ’We reduced the induced gait and cognitive differences by matching the patients per age and sex.’ Please revise for consistency. We would like to thank the reviewer for this comment. We revised the text, as: “The study population consisted of children with CP between the ages of 8 and 16 years with level I or II according to the Gross Motor Function Classification System (GMFCS) (23), as well as age and sex-matched children with TD. The sample consisted of two groups, children with CP (CP group) and age and sex-matched children with TD (TD group). Children were age matched with peers, with a range of ±1.5 years.” • Participants. Dysarthria with difficulties coordinating the muscles used for speaking and coordination of breathing, is more frequent in children with CP. This could potentially influence the tests (cognitive tasks requiring talk: numbers, fruits, animals and be worse while walking rapidly). If none of the children had dysarthria this might be worth mentioning in the method section. If not, it could be mentioned as a limitation. Thank you for this remark. This is a very important topic. Probably because we merely had children with low GMFCS level, we didn’t have patients with dysarthria. We added it to the method section as you suggested. “None of the children had dysarthria.” RESULTS • Table 1. According to the characteristics of the participants, the height and especially the mean weight of the study group (CP) exceeds the values of the control group (TD) by 10 kg. This is quite unusual, and typically we see the reversed pattern with more underweight in children with CP than in TP children. Currently the weight range is reported as 21 to 107 kg in the children with CP and that is unusually high. Are these values correct ? If so, please highlight also in the discussion. We thank the reviewer for this question. These values are correct. As this seems unusual, we had to have a look at the statistical differences between the groups. This was executed with a t-test. It occurs that the two groups were not statistically different. Therefore it seemed important to mention it in the results as: “The two groups had similar weight (p=0,09) and height (p=0,53).” As suggested, we mentioned it in the discussion: “Also, probably because of the low GMFCS level of the participants with CP, the two groups were statistically similar in weight and height.” • Table 3, it is interesting that children with CP seem to have the same cadence as TD children during all three conditions, even though step length is slightly shorter. I think this could be mentioned in the discussion. Thank you for this suggestion. We took this comment into great consideration and adapted the discussion as: “We expected certain differences in gait parameters between both groups. For all three tasks the step length was consistently lower in the CP group. Moreover, the difference between both groups became greater under increased dual-task difficulty. However, we observed that both groups had similar cadence, that decreased similarly in each group when the task became more difficult. It is therefore possible that in children with CP the spatial components of movement programming are more strongly impacted by dual-tasks than its temporal components, when compared to TD children.” • Figures. Page 6 (line 202) you refer to Figure 1A and 2B for gait stability AP and ML directions. I think this should be Figure 2A and 2B. Figure 1 illustrating Foot Placement Estimator Values is presented at page 4. We would like to thank the reviewer for this comment. We could not find this mistake, but we still adapted on the text from « Fig 2 » to « Fig 2A and 2B show the distribution of the two…” for more clarity. Other small changes had to be done due to new spotted mistakes or adjustments in order to meet PLOS ONE’style requirement. These are visible in the marked up copy. We would like to change our Financial Disclosure and Funding Information as: This work was supported by a convention (2015/1) by La Fondation Paralysie Cerebrale (Paris, France, https://www.fondationparalysiecerebrale.org/). Sjoerd M.Bruijn was funded by a VIDI grant (016.Vidi.178.014) from the Dutch Organization for Scientific Research (NOW, https://www.nwo.nl/en). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript." We would like to adjust the amended statment as : « The authors thank the participants and their families. We also thank Nathalie Valenza for her contributions in choosing the cognitive tasks and participating in the protocol design. We thank Antoine Poncet for his help on the statistical analysis.” We will join the data as supporting information files in the form of two excel documents. One of the mistakes was about the reference n°39, which is “Chakraborty S, Nandy A, Kesar TM. Gait deficits and dynamic stability in children and adolescents with cerebral palsy: a systematic review and meta-analysis. Clinical biomechanics. 2019. ». We cited wrongfully « Chakravarthy et all ». Best regards, Sophie Wist Attachments Attachment Submitted filename: Responses-to-reviewers.docx https://doi.org/10.1371/journal.pone.0270145.r002
6 Jun 2022 Decision Letter - Yury Ivanenko, Editor Gait stability in ambulant children with cerebral palsy during dual tasks PONE-D-22-05897R1 Dear Dr. Wist, 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, Yury Ivanenko Academic Editor PLOS ONE Additional Editor Comments (optional): 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 #1: 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 #1: Yes ****** 3. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: 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 #1: 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 #1: 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 #1: The authors addressed all of my concerns and I endorse this manuscript for publication. This is a highly relevant topic. ****** 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 #1: No ******** https://doi.org/10.1371/journal.pone.0270145.r003
Formally Accepted
13 Jun 2022 Acceptance Letter - Yury Ivanenko, Editor PONE-D-22-05897R1 Gait stability in ambulant children with cerebral palsy during dual tasks Dear Dr. Wist: 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. Yury Ivanenko Academic Editor PLOS ONE https://doi.org/10.1371/journal.pone.0270145.r004

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