Effect of Individualized Whole-Body Vibration Exercise on Locomotion and Postural Control in a Person with Multiple Sclerosis: A 5-Year Case Report

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This study investigated the long-term effects of individualized WBV. The findings showed improved locomotion, balance, and grip strength. Given the length of the treatment, the case report would be valuable, but the manuscript needs some improvement.

 

I think the hypothesis is well derived. However, it would be better to explain the mechanistic rationale for why WBV might influence grip strength, which is an upper-body outcome, when the vibration stimulus is lower-body focused.

 

Technical details are missing. The authors mentioned that the raw EMG signals were used directly to calculate RMS, but did not report any normalization procedure (e.g., to MVIC). This is a critical issue, especially given the multi-year design and comparisons across limbs and sessions.

 

In addition, the RMS computation method is not replicable. Key details such as window size, stride averaging procedure, and software used are missing.

 

I think it would be better to include kinematic time-series data in the first panel of Figure 4.

 

The purpose of including MRI data is unclear. Was it intended to confirm safety only, or was it expected to relate to functional outcomes?

 

I think an important aspect was not addressed: muscle fatigue, which is also a key factor in MS. Given that muscle fatigue is often estimated using EMG signals, it should not be overlooked. It can be assessed using metrics such as median frequency shift or zero-crossing, as demonstrated in [1]. At the very least, the authors should discuss this point and provide examples of how EMG can be used to estimate fatigue. Including such a discussion would help strengthen the interpretation of the EMG data.

[1] https://doi.org/10.1007/s13534-018-0078-z

 

The fact that this is a within-subject study does not excuse the absence of statistical tests. Even in single-case designs, basic statistical analysis is important to support the interpretation of changes over time. I think the authors should report appropriate statistical results to support their findings.

Author Response

Reviewer 1.

 

This study investigated the long-term effects of individualized WBV. The findings showed improved locomotion, balance, and grip strength. Given the length of the treatment, the case report would be valuable, but the manuscript needs some improvement.

Firstly, we would like to thank you for your comprehensive review of our paper. Your comments helped us to rethink our study and paper. It was very useful. As you can see, we accepted many of your suggestions, rewriting, rephrasing the paper. However, in some cases we tried to give answers to your questions and to reason for our opinion. We would like kindly to ask you to accept our answers and propose our paper be accepted for publication. Thank you very much for your kind assistance in advance. 

Blue letters show your comments and questions. Red fold letters indicate our answers. Corrections were made in the text with red letters.

 

1. Reviewer comment:

-I think the hypothesis is well derived. However, it would be better to explain the mechanistic rationale for why WBV might influence grip strength, which is an upper-body outcome when the vibration stimulus is lower-body focused.

1. Author’s response:

We appreciate your suggestion. We have included a paragraph in the text of the manuscript (page 3, line 118 to line 125).

 

2. Reviewer comment:

 Technical details are missing. The authors mentioned that the raw EMG signals were used directly to calculate RMS, but did not report any normalization procedure (e.g., to MVIC). This is a critical issue, especially given the multi-year design and comparisons across limbs and sessions.

2. Author’s response:

Considering your comment, we have reanalysed the sEMG data during the stance phase of gait by normalizing the EMG values to the peak value of each muscle during the stance phase in each assessment session. This normalization procedure is considered appropriate for the analysis of EMG data during stance phase, as it shows less variability in muscle activity [70]. We have corrected it in the text (page 8, line 279-281).

 

3. Reviewer comment:

 -In addition, the RMS computation method is not replicable. Key details such as window size, stride averaging procedure, and software used are missing.

Author’s response:

In the section “2.5 Surface electromyography (sEMG)” we have added an explanation of how the data were processed by using the software (MuscleLab 6000). (Page 7, lines 241-249)

 

4. Reviewer comment:

 -I think it would be better to include kinematic time-series data in the first panel of Figure 4.

4. Author’s response:

The first panel of Figure 3 (correct numbering) represents the EMG activity of the muscles, recorded during the contact phase. The kinematic changes of the steps in different phases of gait (over time) are represented utilizing the angle-angle diagram. Since this representation constitutes the metric used to study gait analysis, we did not prefer to modify the figure. In addition, we have added some details that help the reader to better understand the content.

 

5. Reviewer comment:

 -The purpose of including MRI data is unclear. Was it intended to confirm safety only, or was it expected to relate to functional outcomes?

5. Author’s response:

MRI is a key component in the diagnosis and treatment of MS as it helps to assess any cortical and spinal cord changes in response to the specificity of the intervention [61]. The participant's clinical routine MRIs were included to assess the long-term WBV intervention and the possibility of WBV that could induce changes in the participant's cortical lesions. We clarified this further in the manuscript (Page 4, lines 176-178).

 

6. Reviewer comment:

 I think an important aspect was not addressed: muscle fatigue, which is also a key factor in MS. Given that muscle fatigue is often estimated using EMG signals, it should not be overlooked. It can be assessed using metrics such as median frequency shift or zero-crossing, as demonstrated in [1]. At the very least, the authors should discuss this point and provide examples of how EMG can be used to estimate fatigue. Including such a discussion would help strengthen the interpretation of the EMG data. [1] https://doi.org/10.1007/s13534-018-0078-z

6. Author’s response:

We agree with you that muscle fatigue is a key factor in MS. However, since the tasks that the participant performed (walking, balance, and grip strength) lasted only a few seconds; therefore, the measures were unable to capture the muscle fatigue. To assess any improvement in muscle fatigue, we should have included a test with a longer duration to induce fatigue and assess it over time (i.e. monitoring the EMG median frequency). Nevertheless, considering the importance of this variable in this population, we have decided to add this aspect to the limitation section. (Page 18, lines 672-683).

 

7. Reviewer comment:

 The fact that this is a within-subject study does not excuse the absence of statistical tests. Even in single-case designs, basic statistical analysis is important to support the interpretation of changes over time. I think the authors should report appropriate statistical results to support their findings.

7. Author’s response:

Considering the reviewers' comments, we have decided to include a statistical analysis of the results using a linear regression model. We added the details of the 'analysis in the text of the manuscript in section 2.12 “statistics and data analysis” (Page 10, lines 390-394). The results were included in the results section.

Reviewer 2 Report

Comments and Suggestions for Authors

REVIEW REPORT (applsci-3587970)

 

Effect of Individualized Whole-Body Vibration Exercise on Locomotion and Postural Control in a Person with Multiple Sclerosis: a 5-year Case Report

 

INTRODUCTION

1. Although I think the literature review is long, the introduction is ok. However, as a minor recommendation, I suggest that the authors consider reviewing the long citations that can be summarized. Furthermore, since there are many abbreviations and this makes the text less dynamic, I recommend reviewing the entire manuscript so that they are properly mentioned at the first mention.
2. The authors assume that WBV has a positive effect on motor recruitment, but how do these mechanisms translate into functional improvements in practice?

METHODS

3. The authors should better describe the selection information of the participant in question. For example: why was this specific participant chosen? Were there other potential participants who were not included? Is the participant's condition (benign diagnosis, previous use of the orthosis, active lifestyle) representative of the RRMS population? Although I understand the complexity surrounding the logistics over the five years (including attrition), it is necessary to include an explanation as to why a single case study was chosen.
4. Please include information about the training of the evaluators and how intra- and inter-individual variability was minimized.
5. Authors should provide the precise location of the sEMG sensors and the parameters for data analysis.

RESULTS

7. Conclusions about the effects of whole-body vibration on postural control, muscle strength, and locomotion are presented without statistical support. For example, improvements in sEMG variables, joint angles, and CoP displacement are described as “increased” or “decreased,” but there are no statistical tests to prove significance.
8. Comparisons between T0, T1, T2, etc. do not include p-values, which makes it difficult to classify the clinical significance of the observed differences.
9. The symmetry index was calculated for several variables. Why was some type of test, such as analysis of variance (ANOVA) or nonparametric tests, used to assess asymmetry over time?

DISCUSSION

10. The authors were pleased to find promising results, but the relationship between the findings and clinical practice needs to be improved, as it is not clear how the whole-body vibration protocol can be applied in clinical settings or incorporated into rehabilitation programs. In addition, there is a lack of information on how the observed improvements in locomotion, postural control, and grip strength can directly impact the functional independence of patients with multiple sclerosis. The authors should highlight this information clearly in the first paragraph.
11. The authors need to better discuss the underlying physiological mechanisms that may explain the observed effects (e.g., tonic vibration reflexes, motor unit recruitment, or hormonal changes).
12. Please prioritize discussing each clinical outcome (e.g., improvement in grip strength, balance, dorsiflexion) with direct implications for daily activities, such as walking on uneven terrain, climbing stairs, or performing household chores.
13. Regarding limitations, authors should delve deeper into important challenges, such as external validity (representativeness of a single participant), the effects of interruption due to the pandemic, and the absence of a control group.

Author Response

Reviewer 2.

 

Firstly, we would like to thank you for your comprehensive review of our paper. Your comments helped us to rethink our study and paper. It was very useful. As you can see, we accepted many of your suggestions, rewriting, rephrasing the paper. However, in some cases we tried to give answers to your questions and to reason for our opinion. We would like kindly to ask you to accept our answers and propose our paper be accepted for publication. Thank you very much for your kind assistance in advance. 

Blue letters show your comments and questions. Red letters indicate our answers. Corrections were made in the text with red letters.

 

Introduction

1. Reviewer comment:

Although I think the literature review is long, the introduction is ok. However, as a minor recommendation, I suggest that the authors consider reviewing the long citations that can be summarized. Furthermore, since there are many abbreviations and this makes the text less dynamic, I recommend reviewing the entire manuscript so that they are properly mentioned at the first mention.

1. Author’s response:

We have followed your suggestions: where possible, we have reduced the number of citations by using references that could summarize the concepts of the sentences. In addition, we have reduced the number of abbreviations using full terms where applicable, and we have reviewed the manuscript to ensure that the abbreviations are properly mentioned at their first use.

 

2. Reviewer comment:

The authors assume that WBV has a positive effect on motor recruitment, but how do these mechanisms translate into functional improvements in practice?

2. Author’s response:

We have integrated a more in-depth explanation into the text (Page 2, Line 84 to 90).

 

Methods

3. Reviewer comment:

The authors should better describe the selection information of the participant in question. For example: why was this specific participant chosen? Were there other potential participants who were not included? Is the participant's condition (benign diagnosis, previous use of the orthosis, active lifestyle) representative of the RRMS population? Although I understand the complexity surrounding the logistics over the five years (including attrition), it is necessary to include an explanation as to why a single case study was chosen.

3. Author’s response:

We have corrected the text by adding a more specific description to motivate the choice of the experimental design. (Page 4, lines 151-158).

 

4. Reviewer comment:

Please include information about the training of the evaluators and how intra- and inter-individual variability was minimized.

4. Author’s response:

Thanks for your suggestion, we have included this information in the text. (Page 4, lines 176-178).

 

5. Reviewer comment:

Authors should provide the precise location of the sEMG sensors and the parameters for data analysis.

5. Author’s response:

By keeping in mind, the length of the entire manuscript, we did not want to dwell on the explanation regarding electrode placement since it was conformed to the international recommendations reported in Surface EMG for Non-Invasive Assessment of Muscles (SENIAM), (line 229 of the manuscript). We have added an explanation of how the data were processed by the software.  We have used the MuscleLab 6000 (section 2.5 “Surface electromyography sEMG”) (Page 7, lines 241-249).

 

Results

7. Reviewer comment:

Conclusions about the effects of whole-body vibration on postural control, muscle strength, and locomotion are presented without statistical support. For example, improvements in sEMG variables, joint angles, and CoP displacement are described as “increased” or “decreased,” but there are no statistical tests to prove significance.

7. Author’s response:

Considering the reviewers' comments, we have decided to include a statistical analysis of the results using a linear regression model. We have added the details in the text (section 2.12 “statistics and data analysis”) (Page 10, lines 390-394). The results have been included in the results section.

 

8. Reviewer comment:

Comparisons between T0, T1, T2, etc. do not include p-values, which makes it difficult to classify the clinical significance of the observed differences.

8. Author’s response:

 We have included the p-values in the different result sections, and we have specified each variable in the respective tables (table S1-S5).

 

9. Reviewer comment:

The symmetry index was calculated for several variables. Why was some type of test, such as analysis of variance (ANOVA) or nonparametric tests, used to assess asymmetry over time?

9. Author’s response:

To understand if the variations of symmetry index over time were statistically significant, we used the linear regression model. We have added this information to the manuscript.

 

Discussion

10. Reviewer comment:

The authors were pleased to find promising results, but the relationship between the findings and clinical practice needs to be improved, as it is not clear how the whole-body vibration protocol can be applied in clinical settings or incorporated into rehabilitation programs. In addition, there is a lack of information on how the observed improvements in locomotion, postural control, and grip strength can directly impact the functional independence of patients with multiple sclerosis. The authors should highlight this information clearly in the first paragraph.

10. Author’s response:

We have included a description paragraph at the beginning of the discussion section (Page 14, lines 489-495).

 

11. Reviewer comment:

The authors need to better discuss the underlying physiological mechanisms that may explain the observed effects (e.g., tonic vibration reflexes, motor unit recruitment, or hormonal changes).

11. Author’s response:

Reviewer 3 Report

Comments and Suggestions for Authors

Dear Authors,

The manuscript presents a comprehensive 5-year case study on the effects of individualized Whole-Body Vibration (WBV) exercise on locomotion, postural control, and handgrip strength in a 68-year-old male with relapsing-remitting multiple sclerosis (RRMS). The manuscript is well-structured, and the methodology is presented in detail. The results provide valuable insights into the application of WBV in different treatments. 

I think that the quality of the manuscript can be improved. Please see my comments below:

- The case study design is appropriate for exploring long-term effects, but the findings cannot be generalized. The authors should explicitly acknowledge this limitation and recommend future multi-subject studies as future work.

- The Figure numbering is not correct.

- Tables S1-S5 are referenced in the main text (results section) but not included in the manuscript. I think that they should be included in the main text.

- Clarify how the progression of WBV workload (Table 1) was determined.

- Expand the discussion to compare results with other WBV studies (e.g., conflicting findings from https://doi.org/10.2340/16501977-0609 and https://doi.org/10.1177/1352458511423267 ).

- The participant’s reported benefits (e.g., improved sleep, mood) are valuable but anecdotal.

- Define all abbreviations at first use. Please check and include full terms where applicable.

Comments on the Quality of English Language

 Minor grammatical errors exist. The manuscript can benefit from language editing and proofreading.

Author Response

Reviewer 3.

Dear Authors,

The manuscript presents a comprehensive 5-year case study on the effects of individualized Whole-Body Vibration (WBV) exercise on locomotion, postural control, and handgrip strength in a 68-year-old male with relapsing-remitting multiple sclerosis (RRMS). The manuscript is well-structured, and the methodology is presented in detail. The results provide valuable insights into the application of WBV in different treatments. 

I think that the quality of the manuscript can be improved. Please see my comments below:

 

Firstly, we would like to thank you for your comprehensive review of our paper. Your comments helped us to rethink our study and paper. It was very useful. As you can see, we accepted many of your suggestions, rewriting and rephrasing the paper. However, in some cases we tried to give answers to your questions and to reason for our opinion. We would kindly like to ask you to accept our answers and propose our paper be accepted for publication. Thank you very much for your kind assistance in advance. 

Blue letters show your comments and questions. Red letters indicate our answers. Corrections were made in the text by red letters.

 

1. Reviewer comment:

The case study design is appropriate for exploring long-term effects, but the findings cannot be generalized. The authors should explicitly acknowledge this limitation and recommend future multi-subject studies as future work.

1. Author’s response:

We have expanded the manuscript with a specific section. (page 18, line 672-683).

 

2. Reviewer comment:

The Figure numbering is not correct.

2. Author’s response:

The numbering of the figures have been corrected.

 

3. Reviewer comment:

- Tables S1-S5 are referenced in the main text (results section) but not included in the manuscript. I think that they should be included in the main text.

3. Author’s response:

As the manuscript is long and has plenty of information, to facilitate its readability, we have decided not to include the tables (S1-S5) in the main text.

 

4. Reviewer comment:

Clarify how the progression of WBV workload (Table 1) was determined.

4. Author’s response:

We have clarified in the text how the workload was increased (Page 5, lines 210-212).

 

5. Reviewer comment:

Expand the discussion to compare results with other WBV studies (e.g., conflicting findings from https://doi.org/10.2340/16501977-0609 and https://doi.org/10.1177/1352458511423267).

5. Author’s response:

We have implemented the discussion section in several parts, clarifying and better specifying some aspects regarding our results.

6. Reviewer comment:

- The participant’s reported benefits (e.g., improved sleep, mood) are valuable but anecdotal.

Author’s response:

We specified in the text (Page 13, line 479 and page 17 line 614).

 

8. Reviewer comment:

- Define all abbreviations at first use. Please check and include full terms where applicable.

8. Author’s response:

We have reduced the number of abbreviations using full terms where applicable, and we have reviewed the manuscript to ensure that the abbreviations are properly mentioned at first use.

 

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

I have no other comments. 

Reviewer 2 Report

Comments and Suggestions for Authors

None

Reviewer 3 Report

Comments and Suggestions for Authors

Thank you for addressing the comments. I have no further comment. Good luck.