The Design of a Smart Lower-Limb Prosthesis Supporting People with Transtibial Amputation—A Data Acquisition System

Round 1

Reviewer 1 Report

This paper presents the design of a smart lower-limb prosthesis for people with TA. This preliminary study needs much more to modify due to incomplete writing.

1)In reference survey, more comments are required for your design and others.

2)In introduction, the sentences “The paper is organized as follows: Sections 2  Section 3  Section 4 Finally, Section 5 is devoted to our conclusions on the tests and results obtained……” are not complete.

3) Design including assembly components should be indicated in Fig.1 and Fig 2., also what are the considered design parameters

4)Actuation figure should be shown, i.e.  how to control rheological fluid, ….

5) A picture for control circuit including sensory peripheral should be presented.

6)The performance of  Lower-Limb Prosthesis  should be described and compared in detailed.

7)More discussions are needed in test results.

8)More words in conclusion must be added.

Author Response

Thank you for giving us the opportunity to submit a revised draft of the manuscript. We appreciate the time and effort that you dedicated to providing feedback on our manuscript and we are grateful for the insightful comments on, and valuable improvements suggested for our paper. We have addressed the suggestions, and the changes are highlighted within the manuscript. Please see below, in blue, for a point-by-point response.

• In reference survey, more comments are required for your design and others.

Thank you for your suggestion, we updated the Introduction section accordingly

• In introduction, the sentences “The paper is organized as follows: Sections 2  Section 3  Section 4 Finally, Section 5 is devoted to our conclusions on the tests and results obtained……” are not complete.

Thank you for your suggestion. It seems that somehow, due a material error, this draft paragraph remained in the submitted version of the paper. It has been modified accordingly.

• Design including assembly components should be indicated in Fig.1 and Fig 2., also what are the considered design parameters

Thank you for your suggestion, we updated Fig.1 and Fig 2.

• Actuation figure should be shown, i.e.  how to control rheological fluid, ….

Thank you for your suggestion, we updated this information in Section 2.1

• A picture for control circuit including sensory peripheral should be presented.

Thank you for your suggestion, we updated our paper and now this information is presented in Fig. 8

• More discussions are needed in test results.

Thank you for your input, we expanded the Results section

• More words in conclusion must be added.

Thank you for your input, we expanded the Conclusion section

Author Response File: Author Response.docx

Reviewer 2 Report

The authors tried to design a smart lower-limb prosthesis that could benefit people with lower-limb amputation. However, the paper, especially the methods and results, were presenting the validation of insole sensors for gait prediction. 

Line 35: “East.” is an extra word here.

Line 36-37: The prevalence of people with amputation worldwide should be referenced.

Line 38: please double-check the accuracy of the numbers referred. Reference one cited stated that “more than 30,000 below-knee and more than 20,000 above-knee amputations were performed in 2013”. I suggest the authors refer to more reliable and validated resources for the prevalence and more recent numbers.

Line 43: There were no descriptions of the prosthetic, yet the authors stated that “there is a need for new prosthetic technologies.” Were the problems expressed in lines 41-42 caused by prosthetic technologies?

Line 43-45: need rewrite. Not clear and is difficult to follow.

Line 60: The aims of this paper were not developed based on a clear justification. The previous session briefly summarized some of the research on prostheses but had no discussions on the cost. It is not clear why a low-cost prosthesis was needed. Several projects have been working on a low-cost prosthesis for lower-limb support, such as the works of Dr. Amos Winter (publications: Murthy Arelekatti, V. N., and Winter, A. G., V (April 5, 2018). "Design and Preliminary Field Validation of a Fully Passive Prosthetic Knee Mechanism for Users With Transfemoral Amputation in India." ASME. J. Mechanisms Robotics. June 2018; 10(3): 031007. https://doi.org/10.1115/1.4039222; Narang YS, Arelekatti VN, Winter AG. The Effects of Prosthesis Inertial Properties on Prosthetic Knee Moment and Hip Energetics Required to Achieve Able-Bodied Kinematics. IEEE Trans Neural Syst Rehabil Eng. 2016 Jul;24(7):754-63. DOI: 10.1109/TNSRE.2015.2455054. Epub 2015 Jul 13. PMID: 26186794), the review paper (J.K. Pinto Maquilon, M.C. Velasquez, Durability of lower limb prostheses with low-cost exoskeletal technology, in patients with lower limb amputation due to any cause, Annals of Physical and Rehabilitation Medicine, Volume 61, Supplement, 2018, Pages e470-e471, ISSN 1877-0657, https://doi.org/10.1016/j.rehab.2018.05.1099.). The authors need to revise the introduction session to justify better why their work was needed and what problems they are trying to address.

Line 69-72: Incomplete information was provided with just the section number.

Line 76-91: I do not see why this should be part of the prosthesis design. Those are just common-sense statements.

Figure 1 did not add much value to the paper. What does smart prosthesis mean? The same for Figure 2; what do smart fluids mean? How does the spherical joint work? Where will the spherical joint locate in the smart prosthesis in Figure 1? The text from lines 96-105 was difficult to follow as they were not linked to Figure 2.

Line 120-125: What did elastic elements mean? Those should be clearly labeled in a Figure to illustrate the concept.

Line 126-131: What kind of sensors were used? Where were the sensors located, and how were they powered?

Line 139-140: Reference should be provided if you mentioned a known ankle prosthesis.

Line 158-171: Very difficult to follow with many statements without references support. In addition, this is the method session but seems to justify the development of an insole sensor. There are so many low-cost insole sensors for rehabilitation purposes that I am not sure I got the points here.

Line 175-176: I’m afraid that I must disagree with this statement. Many of the sensor development papers were thoroughly validated. The authors will need to provide evidence if they tend to say so.

Line 308-309: I did not get how those three sensors could not provide reliable and repeatable data. What were the criteria for making the decision?

Line 329: “X” healthy persons?

Figure X.3.3.2. What were the 8 phases mean?

The specifications of the sensors were not provided. The justifications for the locations of the sensors were not provided.

The validation of the output of the sensor was not provided. How do you know the sensors were predicting the right gait kinematics?

Author Response

Thank you for giving us the opportunity to submit a revised draft of the manuscript. We appreciate the time and effort that you dedicated to providing feedback on our manuscript and we are grateful for the insightful comments on, and valuable improvements suggested for our paper. We have addressed the suggestions, and the changes are highlighted within the manuscript. Please see below, in blue, for a point-by-point response.

• Line 35: “East.” is an extra word here.

Thank you, we corrected this material error.

• Line 36-37: The prevalence of people with amputation worldwide should be

Thank you for your suggestion, we updated our paper, the prevalence of people with amputation worldwide is now referenced.

• Line 38: please double-check the accuracy of the numbers referred. Reference one cited stated that “more than 30,000 below-knee and more than 20,000 above-knee amputations were performed in 2013”. I suggest the authors refer to more reliable and validated resources for the prevalence and more recent numbers.

Thank you for your suggestion, we modified this part of the introduction.

• Line 43: There were no descriptions of the prosthetic, yet the authors stated that “there is a need for new prosthetic technologies.” Were the problems expressed in lines 41-42 caused by prosthetic technologies?

Thank you for your suggestion, we updated the Introduction section accordingly.

• Line 43-45: need rewrite. Not clear and is difficult to follow.

Thank you for your suggestion, we have reformulated that phrase.

• Line 60: The aims of this paper were not developed based on a clear justification. The previous session briefly summarized some of the research on prostheses but had no discussions on the cost. It is not clear why a low-cost prosthesis was needed. Several projects have been working on a low-cost prosthesis for lower-limb support, such as the works of Dr. Amos Winter (publications: Murthy Arelekatti, V. N., and Winter, A. G., V (April 5, 2018). "Design and Preliminary Field Validation of a Fully Passive Prosthetic Knee Mechanism for Users With Transfemoral Amputation in India." ASME. J. Mechanisms Robotics. June 2018; 10(3): 031007. https://doi.org/10.1115/1.4039222; Narang YS, Arelekatti VN, Winter AG. The Effects of Prosthesis Inertial Properties on Prosthetic Knee Moment and Hip Energetics Required to Achieve Able-Bodied Kinematics. IEEE Trans Neural Syst Rehabil Eng. 2016 Jul;24(7):754-63. DOI: 10.1109/TNSRE.2015.2455054. Epub 2015 Jul 13. PMID: 26186794), the review paper (J.K. Pinto Maquilon, M.C. Velasquez, Durability of lower limb prostheses with low-cost exoskeletal technology, in patients with lower limb amputation due to any cause, Annals of Physical and Rehabilitation Medicine, Volume 61, Supplement, 2018, Pages e470-e471, ISSN 1877-0657, https://doi.org/10.1016/j.rehab.2018.05.1099.). The authors need to revise the introduction session to justify better why their work was needed and what problems they are trying to address.

Thank you for your recommendation, we updated this part of the introduction accordingly. We related our work to these additional citations.

• Line 69-72: Incomplete information was provided with just the section number.

Thank you for your suggestion. It seems that somehow, due a material error, this draft paragraph remained in the submitted version of the paper. It has been modified accordingly.

• Line 76-91: I do not see why this should be part of the prosthesis design. Those are just common-sense statements.

Figure 1 did not add much value to the paper. What does smart prosthesis mean? The same for Figure 2; what do smart fluids mean? How does the spherical joint work? Where will the spherical joint locate in the smart prosthesis in Figure 1? The text from lines 96-105 was difficult to follow as they were not linked to Figure 2.

Thank you for your recommendation, we updated sub-section 2.1 accordingly. The spherical joint design and function was detailed.  Now we indicate the smart fluid type we are using. We reformulate the paragraph accordingly.

• Line 120-125: What did elastic elements mean? Those should be clearly labeled in a Figure to illustrate the concept.

Thank you for your recommendation, we updated Section 2.1 accordingly.

• Line 126-131: What kind of sensors were used? Where were the sensors located, and how were they powered?

Thank you for your recommendation, we updated Section 2.2 accordingly.

• Line 139-140: Reference should be provided if you mentioned a known ankle prosthesis.

Thank you for your recommendation, this information has now been included.

• Line 158-171: Very difficult to follow with many statements without references support. In addition, this is the method session but seems to justify the development of an insole sensor. There are so many low-cost insole sensors for rehabilitation purposes that I am not sure I got the points here.

Thank you for your input, we rephrased the paragraph.

• Line 175-176: I’m afraid that I must disagree with this statement. Many of the sensor development papers were thoroughly validated. The authors will need to provide evidence if they tend to say so.

Thank you for your input, we rephrased the paragraph

• Line 308-309: I did not get how those three sensors could not provide reliable and repeatable data. What were the criteria for making the decision?

Thank you for your question, we presented our criteria and justification for rejecting the three sensors.

• Line 329: “X” healthy persons?

Thank you for your suggestion. It seems that somehow, due a material error, this draft paragraph remained in the submitted version of the paper. It has been modified accordingly.

• Figure X.3.3.2. What were the 8 phases mean?

Thank you for your suggestion. It seems that somehow, due a material error, this draft paragraph remained in the submitted version of the paper. It has been modified accordingly.

• The specifications of the sensors were not provided. The justifications for the locations of the sensors were not provided.

This information was presented in Section 2.2

• The validation of the output of the sensor was not provided. How do you know the sensors were predicting the right gait kinematics?

Thank you for your input, we inserted the references to the materials we studied in order to validate our data readings.

Author Response File: Author Response.docx

Reviewer 3 Report

The design of prosthesis for amputated people is highly needed over the world so that this work could attract some attention in the rehabilitation community. However, regarding the present version，I have to regect it for the following reasons.

(1) The paper is not complete without conclusions!!

(2) In Page 2, there are no descriptions about the struture of this paper. Section2/section 3/section 4? It should be written in details.

(3) In Abstract, it can be better to include some conclusion of this comparison. For example, how about the accuracy/error for the proposed system.

(4) It is better to include at least four key words for the readers to search your work.

(5) The full meaning should be explicitly denoted before using abbreviation at the first time. For example, UEA/LEA.

(6) In Introduction, page 2, the difference between the mechanical properties and the length of the prosthesis should be explained. For my point of view, the length of the prosthesis belongs to the mechanical properties.

Author Response

Thank you for the time and effort that you dedicated to providing feedback on our manuscript and we are grateful for the insightful comments on, and valuable improvements suggested for our paper. We have addressed the suggestions, and the changes are highlighted within the manuscript. Please see below, in blue, for a point-by-point response.

• The paper is not complete without conclusions!!

Thank you for your input, we developed the Conclusion section

• In Page 2, there are no descriptions about the struture of this paper. Section2/section 3/section 4? It should be written in details.

Thank you for your input. It seems that somehow, due a material error, this draft paragraph remained in the submitted version of the paper. It has been modified accordingly.

• In Abstract, it can be better to include some conclusion of this comparison. For example, how about the accuracy/error for the proposed system.

Thank you for your input, we reformulated the Abstract section

• It is better to include at least four key words for the readers to search your work.

Thank you for your suggestion. We updated the keywords accordingly

• The full meaning should be explicitly denoted before using abbreviation at the first time. For example, UEA/LEA.

Thank you for your input. This information has been changed

• In Introduction, page 2, the difference between the mechanical properties and the length of the prosthesis should be explained. For my point of view, the length of the prosthesis belongs to the mechanical properties.

Thank you for your suggestion. This part of the introduction has been modified accordingly

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

This draft has been modified according to the reviewer's comments, and can be accepted.

Author Response

Thank you for your feedback!

Regards,

Reviewer 2 Report

Thank you for working on my previous comments. While some of the comments were addressed, I am still concerned about below:

1. The quality of writing. The authors should carefully proofread the revised version to make it clear. Many typos and grammar errors negatively impact the understanding and readability of the current manuscript.

2. The abstract is very vague and descriptive. If the purpose is on the kinematic and dynamic parameters of the smart prosthesis, the parameters should be reported.

3. The introduction is lengthy and difficult to follow. It would be better to focus on why the smart lower-limb prosthesis is needed, with clear aims and objectives of this study.

4. the team aims to design and implement a low-cost prosthesis, but the cost of the proposed design was not provided.

5. It would be better to start with clear design objectives and a design matrix in the method session. Otherwise, it isn't easy to follow how and why the current design approach was selected. In addition, it isn't easy to evaluate whether the prototype meets the design objectives or not.

6. The critical component of the prosthesis is the spherical joint based on intelligent fluids, but it is unclear to me what intelligent fluids mean. What is the theoretical and experimental performance of such a system? The referred patent (citation number 47) was not accessible. I cannot justify whether this system will work or not based on the current description.

7. There is no information on how the prosthesis will be controlled. What kind of controller was used? It would be helpful to include a control schematic.

8. The results were primarily on the sensor mounted on the sole of the sandal but not results on the spherical joint and the intelligent fluids.

9. It is unclear how the sensor data will be used to detect gait phases. There was just one example showing that the readings from different sensors will be further in different phases, but no algorithms will detect those phases based on the sensor readings.

Author Response

Thank you for your feedback, it really help us to improve our paper.

The according answers are uploaded in the attachment.

Best regards,

Author Response File: Author Response.docx

Reviewer 3 Report

All my comments have been answered. This version can be accepted for publication.

Author Response

Thank you for your feedback!

Regards,

Round 3

Reviewer 2 Report

The paper read much better, and thank you for your effort in revising it. 

I have those additional comments for the current paper:

1. Session 2.1 of prosthesis design was listed in materials and methods, but no results were associated. As the article is focused on the data acquisition system ( which is fine and essential for a new prosthesis system), I suggest removing it or being listed as part of the introduction.

2. Line 208-221. Those are not methods but the background to justify why the proposed data acquisition system was needed.

3. I suggest removing Figure 8 as it did not add much value to the article. Or please provide the hardware diagram instead of the circuit design.

4. It would be better to briefly justify why 1kg, 5kg, and 10kg weights were used. As the maximum load of the sensors is 50kg, and a person's weight, why not test with a heavier weight?

5. It is necessary to describe each test weight (were they the same shapes or sizes) and how they were applied (they were applied to the same location of the prototype or not) to the repeatability test prototype. A figure could be helpful here.

6. Line 388-398: Thank you for adding the homogeneity test measurement protocol, but it is unclear how the results obtained from each sensorial element were compared. Those should be something you had already done; the future sense did not read correctly.

7. Session 2.4 should include the inclusion and exclusion criteria for the healthy participants. How and where they were recruited should be described as well.

8. Line 430-433: It is confused here. Even though the study did not administer medical drugs or invasive physical elements, the study should be approved by IRB. What do you mean "there was no requirement from the Ethical Com-432 mission for research involving human subjects." This was inconsistent with what you stated just before those sentences.

9. Session 3.1 of the repeatability measurements, beyond the SD to mean ratio for the 10kg weight, were there any correlations among the pressure distributions of the same sensor at different weights?

10. Session 3.2 of the homogeneity results: I have difficulty following the results. 

11. Basic demographic information of the ten participants should be provided. The results only showed one participant's data; how about other participants? If one person's data is enough, why were ten participants tested?

12. Line 493-494: These should not be added here. How can a reader tell this? Did the two references use the same method and protocol and show similar results? If you want to discuss the consistency with literature, these should be discussed in the discussion instead of your results.

Author Response

Thank you for giving us the opportunity to improve our manuscript. We appreciate the time and effort that you dedicated to providing feedback on our manuscript and we are grateful for the insightful comments on, and valuable improvements suggested for our paper. We have addressed the suggestions, and the changes are highlighted within the manuscript. Please see on the attached document, marked with blue, the point-by-point response.

Author Response File: Author Response.docx