Motor Indicators for the Assessment of Frozen Shoulder Rehabilitation via a Virtual Reality Training System

Round 1

Reviewer 1 Report

Thanks for your work. I enjoyed reading it. Following are my comments. 

1. can you please divide the age into atleast two age groups.
2. are there any standards that a particular exercise should complete in specific time to say that it is OK.
3. There are chances that subjects hurt themselves maybe get get excited and hit their hands on wall, any such incidents. How likely are these incidents as per your understanding. 
4. It would also nice to see the response of subjects, how did they feel about themselves, what do they feel about the system. How likely are they to recommend your system. 
5. Please share some responses of the subjects.

Author Response

1. can you please divide the age into at least two age groups.

<Reply> Since the number of subjects is small, if we further divide the subjects into two groups, the interpretation of statistical results will be limited. As a result, we keep one group as it is.

2. are there any standards that a particular exercise should complete in specific time to say that it is OK..

<Reply> There is no such standard for now. Instead, the total time, for example one hour, to take exercise is an index to fulfill in clinical practice.

3. There are chances that subjects hurt themselves maybe get get excited and hit their hands on wall, any such incidents. How likely are these incidents as per your understanding. 

<Reply> No report like this. It is probably because subjects are with motor impairment that is less likely to hit the wall accidentally.

4. It would also nice to see the response of subjects, how did they feel about themselves, what do they feel about the system. How likely are they to recommend your system. 

<Reply> The purpose of the paper is to propose motor indices to assess motor function instead of feasibility or usability oriented research. As a result, we do not put response of subject in the paper.

5. Please share some responses of the subjects.

<Reply> Most subjects are more than willing to use the proposed system to perform the rehabilitation. They consider that the system is useful.

Reviewer 2 Report

1. Reference 1 is never cited
2. Please either depict or cite references to elaborate “pulley therapy”, “forward and sideways finger wall walking”, and “towel exercise”.
3. Please elaborate the relevant content of references [4-7] to make their applicable content obvious to the reader, so the reader knows why to go get those reference seeking specific information.
4. Please elaborate the relevant content of references [10-11] to make their applicable content obvious to the reader, so the reader knows why to go get those reference seeking specific information.
5. Lines 55-58 are very confusing, seeming to indicate task performance is not a traditional clinical assessment tools, but furthermore seems to assert that task performance was not utilized (is there some un-emphasized significance for not using it to assess therapeutic effects?).
6. Add references or other graphic depiction to elaborate the Fugl-Meyer Arm Scale and the Manual Function Test especially in light of the immediately previous claim that task performance was not used for assessment. In particular, the “manual function test” certainly sounds like a task performance test.  Pastor et al (lines 62-63) seems to be described as using task performance as an example of not using task performance (in light of lines 55-56).
7. Figure 1 very well elaborates the text in paragraph 2.1, and the verbiage in that paragraph very ties the figure to the text.
8. The use of motor trajectories and task performance described in paragraph 2.2, lines 89-93 elaborate the oddly worded claim in lines 55-58 that neither were used for assessment. Please consider lines 89-93 when rewording lines 55-58.
9. Line 103: spell “four” to avoid confusion, especially in a sentence containing a numerical list of items.
10. Lines 112-113 seem to imply motor trajectories are indeed used (contrary to the assertion of lines 55-58), since the trajectories would seem to be used to form the error signal.
11. Figures 2,3,4,5 transmit no information, since the text within the figure is too small and even when zoomed on an electronic viewing device, the figures become blurred due to low resolution. Merely as a recommendation, the figure captions seem to be the smallest text in the manuscript template, so consider using the size of this text as a visual aid to establish legibility.
12. Spell out “seconds” in line 121.
13. Spell “two” in line 122.
14. Section 3 describes experiments, but no prefacing modeling, analysis, simulation, or prediction was offered, limiting the utility of the study. Nonetheless, the study will provide useful aid to future correlational studies.
15. Paragraph 3.2, lines 167-176: spell out abbreviated quantities to increase clarity, e.g. 20 min, 4 weeks, 7 VR. Please do this throughout the document. For example, “min twice per week” has other obvious meanings that would seem to be different than the authors’ intent.
16. Please move the citation explaining CMS from line 180 to line 175 when the reader will want such a reference.
17. Please re-read the sentence on line 178-179 and line 55-58, which seem self-contradictory.
18. Especially amidst a dearth of modeling, analysis, simulation, and prediction, an extra burden is placed upon clarity of presentation of the experimental results in a manner the readership of Electronics will enjoy. Especially since the readership will likely possess foundational understandings from deterministic relations (Ohm’s law, Kirchoff’s laws, Watts Law, Faraday’s law, Lenz’s law, Coulomb’s law, Gauss’s law, electron current, etc.), in-depth stochastic skills including design of experiments should not be assumed.  Please define all the test quantities listed in tables 2, 3, 4, and the second table 1 on page 8 and tables 6-12 that follow the second table 1, including the quantities in the table footers where applicable. Include an explanation of the significance of the presence of two-tailed sigma test results and clarify if the listed results are P-values and the definition and significance of P-values as well. ASIDE: the authors have done a great job in their pithy explanation of stepwise regression in lines 256-259.
19. Section 5 seems to begin by introducing another, subsequent analysis (perhaps due to grammar).
20. The reviewer deems the authors’ word choice was exactly correct (e.g. “significant correlation”), but nonetheless recommends magnification of the genuineness of the authors: Section 5’s discussion should at least mention the low correlation coefficients and R2 values seen in the study and comment on potentials to improve correlation in future studies.  Seemingly a great place for inclusion of such is in lines 274-278 where assertions of efficacy are claimed (amongst others, e.g. lines 288-290, 296, 303).  Especially in light of the final paragraph of lines 315-317, compliance with this recommendation by the reviewer will enhance the “flow” of the entire paragraph drawing to the concluding paragraph.
21. Was the study was conducted according to the guidelines of the Declaration of Helsinki, and approved by the Institutional Review Board (or Ethics Committee) or otherwise waived; or was alternative compliance validated (e.g. Article 26 in Law of the People’s Republic of China on Medical Practitioners, Article 29 in Drug Administration Law of the People's Republic of China, or Article 29 in Law of the People’s Republic of China on Progress of Science and Technology) to insure safety of human subjects? Please indicate such in accordance with the guidance in the MDPI template.

Author Response

1. Reference 1 is never cited

<Reply> Thank you for pointing this out. One sentence is added to that reference 1 is cited as below:

The goal for frozen shoulder treatments is to maintain and improve shoulder ROM and enhance muscle strength, thereby allowing patients to resume their normal activities as soon as possible [1].

2. Please either depict or cite references to elaborate “pulley therapy”, “forward and sideways finger wall walking”, and “towel exercise”.

<Reply> Thank you for the suggestion. Two references are added as below:

19. Lowe, Catherine Minns, et al. "Clinical effectiveness of non-surgical interventions for primary frozen shoulder: a systematic review." Journal of rehabilitation medicine51.8 (2019): 539-556.
20. Challoumas, Dimitris, et al. "Comparison of treatments for frozen shoulder: a systematic review and meta-analysis." JAMA network open3.12 (2020): e2029581-e2029581.

3. Please elaborate the relevant content of references [4-7] to make their applicable content obvious to the reader, so the reader knows why to go get those reference seeking specific information

<Reply> Thank you for the suggestion. Additional content is added as below:

…which show the feasibility and usability of proposed VR system.

4. Please elaborate the relevant content of references [10-11] to make their applicable content obvious to the reader, so the reader knows why to go get those reference seeking speci Reference 1 is never cited fic information.

<Reply> Thank you for the suggestion. Additional content is added as below:

…, indicating the effectiveness of VR-based rehabilitation system.

5. Lines 55-58 are very confusing, seeming to indicate task performance is not a traditional clinical assessment tools, but furthermore seems to assert that task performance was not utilized (is there some un-emphasized significance for not using it to assess therapeutic effects?).

<Reply> Clinical assessment tools are for traditional assessment. Task performance were proposed for assessment by other VR-related researches. However, our research proposed more advanced indices oriented from motion data for assessment.

6. Add references or other graphic depiction to elaborate the Fugl-Meyer Arm Scale and the Manual Function Test especially in light of the immediately previous claim that task performance was not used for assessment. In particular, the “manual function test” certainly sounds like a task performance test.  Pastor et al (lines 62-63) seems to be described as using task performance as an example of not using task performance (in light of lines 55-56).

<Reply> Sorry for the confusion. Task performance in this paper stands for the outcome of VR or game based tasks. As a result, clinical assessments, such as Fugl-Meyer Arm Scale or the Manual Function Test, are irrelevant with task performance.

7. Figure 1 very well elaborates the text in paragraph 2.1, and the verbiage in that paragraph very ties the figure to the text.

<Reply> Thank you for the comments.

8. The use of motor trajectories and task performance described in paragraph 2.2, lines 89-93 elaborate the oddly worded claim in lines 55-58 that neither were used for assessment. Please consider lines 89-93 when rewording lines 55-58.

<Reply> Sorry for the confusion. Following the reply of previous question, descriptions in lines 89-93 comply with it in lines 55-58

9. Line 103: spell “four” to avoid confusion, especially in a sentence containing a numerical list of items.

<Reply> Thank you for the suggestion. It is fixed.

10. Lines 112-113 seem to imply motor trajectories are indeed used (contrary to the assertion of lines 55-58), since the trajectories would seem to be used to form the error signal.

<Reply> Sorry for the confusion. Traditionally, motor trajectories are not used for assessment. However, motor trajectories are used to derive motor indices in our paper. Therefore, descriptions in lines 112-113 comply with it in lines 55-58

11. Figures 2,3,4,5 transmit no information, since the text within the figure is too small and even when zoomed on an electronic viewing device, the figures become blurred due to low resolution. Merely as a recommendation, the figure captions seem to be the smallest text in the manuscript template, so consider using the size of this text as a visual aid to establish legibility.

<Reply> Thank you for the recommendation. Original pictures are re-sized that the text within the figure is as large as figure captions.

12. Spell out “seconds” in line 121.

<Reply> Thank you for the suggestion. It is fixed.

13. Spell “two” in line 122.

<Reply> Thank you for the suggestion. It is fixed.

14. Section 3 describes experiments, but no prefacing modeling, analysis, simulation, or prediction was offered, limiting the utility of the study. Nonetheless, the study will provide useful aid to future correlational studies.

<Reply> Thank you for the comments.

15. Paragraph 3.2, lines 167-176: spell out abbreviated quantities to increase clarity, e.g. 20 min, 4 weeks, 7 VR. Please do this throughout the document. For example, “min twice per week” has other obvious meanings that would seem to be different than the authors’ intent.

<Reply> Thank you for the suggestion. It is fixed.

16. Please move the citation explaining CMS from line 180 to line 175 when the reader will want such a reference.

<Reply> Thank you for the suggestion. It is fixed.

17. Please re-read the sentence on line 178-179 and line 55-58, which seem self-contradictory.

<Reply> Sorry for the confusion. Clinical assessment is also used as reference in this study. Therefore, descriptions in lines 178-179 comply with it in lines 55-58

18. Especially amidst a dearth of modeling, analysis, simulation, and prediction, an extra burden is placed upon clarity of presentation of the experimental results in a manner the readership of Electronics will enjoy. Especially since the readership will likely possess foundational understandings from deterministic relations (Ohm’s law, Kirchoff’s laws, Watts Law, Faraday’s law, Lenz’s law, Coulomb’s law, Gauss’s law, electron current, etc.), in-depth stochastic skills including design of experiments should not be assumed.  Please define all the test quantities listed in tables 2, 3, 4, and the second table 1 on page 8 and tables 6-12 that follow the second table 1, including the quantities in the table footers where applicable. Include an explanation of the significance of the presence of two-tailed sigma test results and clarify if the listed results are P-values and the definition and significance of P-values as well. ASIDE: the authors have done a great job in their pithy explanation of stepwise regression in lines 256-259

<Reply> Thank you for the suggestions. More explanations about the statistics methods are added in Pg.7 as below:

…Note that the normal approximation was adopted to carry out the test statistic….

…It should be noted that the two-sided test was adopted to determine the p-values. Meanwhile, p-values less than 0.05 were declared to be significant….

Also, Table2~Table12 are fixed as recommended.

19. Section 5 seems to begin by introducing another, subsequent analysis (perhaps due to grammar).

<Reply> Thank you for pointing this out. It is removed.

20. The reviewer deems the authors’ word choice was exactly correct (e.g. “significant correlation”), but nonetheless recommends magnification of the genuineness of the authors: Section 5’s discussion should at least mention the low correlation coefficients and R2 values seen in the study and comment on potentials to improve correlation in future studies.  Seemingly a great place for inclusion of such is in lines 274-278 where assertions of efficacy are claimed (amongst others, e.g. lines 288-290, 296, 303).  Especially in light of the final paragraph of lines 315-317, compliance with this recommendation by the reviewer will enhance the “flow” of the entire paragraph drawing to the concluding paragraph.

<Reply> Thank you for the recommendation. A sentence is added in Pg. 14 to comment on potentials to improve correlation in future studies as below:

…Meanwhile, despite that some motor indices showed low correlation with clinical assessment items, there is still great potential to re-exanimate them if a large scale of clinical trials will be performed in the future.

21. Was the study was conducted according to the guidelines of the Declaration of Helsinki, and approved by the Institutional Review Board (or Ethics Committee) or otherwise waived; or was alternative compliance validated (e.g. Article 26 in Law of the People’s Republic of China on Medical Practitioners, Article 29 in Drug Administration Law of the People's Republic of China, or Article 29 in Law of the People’s Republic of China on Progress of Science and Technology) to insure safety of human subjects? Please indicate such in accordance with the guidance in the MDPI template.

<Reply> Yes, this study is with IRB approval issued by Taipei Veterans General Hospital.