Review Reports

Round 1

Reviewer 1 Report

The main goal of the review is not mentioned by the authors until in Chapter 4, lines 233-234.  It is also appropriate to highlight it at the end of Chapter 1. Introduction.

In general, I found the review to be an clear and well-done article. I recommend it for publication.

Author Response

Please see attached file

Author Response File: Author Response.pdf

Reviewer 2 Report

This paper provides a  very comprehensive review of the current study on metaverse Virtual Reality applications in rehabilitation. The paper is well organized and easy to read with detailed data analysis.

Some minor format issues with the formula on lines 146 and 149.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Thank you for the opportunity to review this interesting manuscript. The purpose of the study has been to study the cybersickness in the rehabilitation setting using metaverse virtual reality. Because the work is a systematic review and meta-analysis, PRISMA statement was followed and I suggest to add in the supplementary materials PRISMA checklist. The topic is actual and interesting, more and more studies will be written in the next years, consequently, after minor revisions, I can suggest its publication.

Minor comments:

-Please, move figure 2 in the results section

-Figure 3. Because most of the information of this figure are in the text, I strongly suggest to remove it.

-Please, move the findings of the meta-analysis in the results section.

-Please, use the discussion to support the findings with other studies, it is not necessary to report the findings here. Figure 4 and 5, and table 3, 4 and 5, according my opinion, are part of the result section.

-As Prisma suggests, please, move the limits of the study and possible future studies at the end of the discussion section

Author Response

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Author Response File: Author Response.pdf

Reviewer 4 Report

The manuscript entitled “Considering the Causes of Cybersickness in Metaverse VR Rehabilitation: Current Research from a Systematic Review and Meta-Analysis” is a Systematic-Review involving 862 individuals with ages ranging from 19 to 95.

The manuscript is misleading from the title and throughout the text because the methodology is not purely focused on the causes of cybersickness in VR but rather on the consequences.

It is incorrect the use of acronyms in the title.

Many sentences are questionable(Abstract, line 11: it is not reliable that VR in the rehabilitation process has become popular in the post-pandemic age; the first sentence in the Introduction is not clear what you mean or too vague or completely wrong; other sentences related to rehabilitation field are not clear or, more easily, not true). 

The concepts related to VR are confused with data related to the use of immersive and non-immersive techniques: lines 73-77 are mentioned exergames. These data are misleading for the analysis of the "metaverse"

The sentences used in lines 44-45, 49-51, 55-61 are clinically questionable.

A clear statement of aim is provided, although the intention probably overstates the capacity of the study.

Please rephrase lines 69-71 because the concept is redundant.

The study design does not seem appropriate to explore the aim of the study. The inclusion and exclusion criteria section is present but is not described in detail. In particular, the sample was not divided into disease categories (the Table is insufficient). This is particularly important for a correct analysis and also for clear results.

The Simulator Sickness Questionnaire (SSQ) was the evaluation parameter used. Nevertheless, the total score of the questionnaire provides information about consequences rather than causes.

 Analysis of the available data looks uninformative and unclear.

In particular, the risk of bias cannot be calculated because two articles did not assign participants to gender groups and one of them even omitted the computation of mean age.

The table included to provide the results should be revised.

The Discussion section is too long, wordy, and partially oriented. The discussion lacks a clear deepening of the available literature.

The results probably overstate the methodological design and the aim of the study. This reflects also in the Discussion.

The organization of this section makes it difficult to distinguish findings from the current study from those of previous reports, despite the citations that are provided. Limitations are noted.

 

Author Response

Please see attached file

Author Response File: Author Response.pdf

Round 2

Reviewer 4 Report

Dear Authors,

your manuscript is substantially lacking from a conceptual point of view both in terms of rehabilitation and analysis of virtual reality.

Every sentence relating to rehabilitation is questionable, since from the abstract.

It is not true that rehabilitation services are getting smarter due to technological development (robotic therapy and mechatronics in the last 20 years). The technological innovation does not imply only the use of virtual reality, as the most advanced phase of current rehabilitation activities is integrated above all with mechatronics, robotics, the use of mechanisms of neurophysiology, and virtual reality systems together, in a structured program of interventions. 

The metaverse is an immersive type of virtual reality different from the classic immersive virtual reality, currently ongoing in the definition (at the moment, a quick search in PubMed with keywords metaverse and virtual reality reveals only 89 articles, with the start in 2021). The metaverse refers to an innovative developing technology. The applications of the metaverse virtual reality in rehabilitation are still minimal. As well, the cybersickness related to the metaverse is not still defined. The cybersickness of immersive virtual reality is another topic.

Another critical issue is related to rehabilitation, described in an excessively simplistic way (the first paragraph of the Introduction). this context is only from the age of intelligence linked to intelligence.

Another critical issue is the clinical context. A symptomatic condition (cognitive impairment) cannot be considered together with a group of disorders with a clear aetiology deriving from lesions of the central nervous system (brain injury) and with a functional status (physical inactivity), a risk factor for other pathologies.

The research is applied to different conditions and not all are of a rehabilitative nature (i.e., physical inactivity in which virtual reality and other rehabilitative interventions are minimal).

Then, the selection of the keywords is questionable. The use of a tool (the questionnaire) as mesh term could be a confounding factor due to a possible conditioning bias.

The used language is severely inefficient. The manuscript is quite fragmented with many elements all together continuously presented, without a logical and continuous articulation. Also, the written form is inadequate.

Finally, it is good to report the changes tracked in the drafts of the manuscript, for fairness to the reviewer, in addition to the responses themselves.

The correct use of the methodology (PRISMA and systems of metanalysis) does not justify the conceptual bias that risks to provide altered results.

Author Response

Dear reviewer，

We would like to thank you for your careful reading, helpful comments, and  writing suggestions, which has significantly improved the presentation of our manuscript.

We have carefully considered all comments from you and revised our manuscript accordingly. The manuscript has also been double-checked, and the typos and grammar errors we found have been corrected. In the following section, we summarize our responses to each comment from the reviewers. We believe that our responses have well addressed all concerns from the reviewers. 

Here are the response:

Point 1: Your manuscript is substantially lacking from a conceptual point of view both in terms of rehabilitation and analysis of virtual reality.

Response 1: We totally agree with your opinion. In order to do introduction for the terms rehabilitation and analysis of virtual reality, we made a progressive conceptual introduction for all of the terms, including VR, rehabilitation, VR rehabilitation, symptoms and cybersickness in 1.Introduction lines 31-115. The detail is shown in the following responses and WORD attachment.

Point 2: Every sentence relating to rehabilitation is questionable, since from the abstract.

Response 2: In order to present an understandable paragraph, we totally retouch the article of course including rehabilitation theory in Abstract. " VR rehabilitation is a rapidly evolving field, with increasing research and development aimed at improving its effectiveness, accessibility, and integration into mainstream healthcare systems. While there are some commercially available VR rehabilitation programs, their adoption and use in clinical practice is still limited." lines 9-13. 

Point 3: It is not true that rehabilitation services are getting smarter due to technological development (robotic therapy and mechatronics in the last 20 years). The technological innovation does not imply only the use of virtual reality, as the most advanced phase of current rehabilitation activities is integrated above all with mechatronics, robotics, the use of mechanisms of neurophysiology, and virtual reality systems together, in a structured program of interventions. 

Response 3: Thank you for your reminder, the contents have changed to "Rehabilitation is crucial in clinical and healthcare scenarios as it enables individuals to regain independence, enhance their quality of life, and reach their full potential in daily activities. Conceptually, rehabilitation is a multifaceted process that aims to restore physical, psychological, and social functioning after a period of illness, injury, or addiction. It takes into account the intricate interplay between biological, psychological, and social factors that may affect a person's capacity to function and achieve their goals. Ultimately, rehabilitation is a process that considers the whole person and their unique circumstances to support them in their journey towards optimal health and well-being.

Manual rehabilitation is deficient in providing consistent and personalized feedback and monitoring. From the user perspective, patients with less motivation and satisfaction mostly result in obsolete applications. What’s more, the characteristics of patients may even determine the degree of recovery from physical or physiological sickness. In this background, many new technologies are seen to be viable options for investigating the possibilities of high-efficiency approaches." in lines 39-52. 

Point 4: The metaverse is an immersive type of virtual reality different from the classic immersive virtual reality, currently ongoing in the definition (at the moment, a quick search in PubMed with keywords metaverse and virtual reality reveals only 89 articles, with the start in 2021). The metaverse refers to an innovative developing technology. The applications of the metaverse virtual reality in rehabilitation are still minimal. As well, the cybersickness related to the metaverse is not still defined. The cybersickness of immersive virtual reality is another topic.

Response 4: We have doubled-check the difference between metaverse and immersive virtual reality, and we decided to changed the title into "Considering the Consequences of Cybersickness in Immersive Virtual Reality Rehabilitation: A Systematic Review and Meta-Analysis"  

All of the words about metaverse in the pages have been removed and retouched. Immersive virtual reality is more suitable for article theme and it is a valuable topic in VR rehab.

Point 5: Another critical issue is related to rehabilitation, described in an excessively simplistic way (the first paragraph of the Introduction). this context is only from the age of intelligence linked to intelligence.

Response 5: We totally agree with you. We have upgraded the Introduction, all the words including VR, rehabilitation, virtual rehabilitation, cybersickness, SSQ questionnaires have do comprehensive introduction. The structure is as follow:

1. VR is developing rapidly; VR is important 2. Rehabilitation is important 3. Manual rehabilitation is deficient. We need new technology for better rehabilitation 4. Introduce VR rehabilitation 5. 3 typical conditions to address: cognitive impairment, brain damage, physical inactivity 6. Introduce Cybersickness in general VR 7. Cybersickness in virtual rehabilitation.

Point 6: Another critical issue is the clinical context. A symptomatic condition (cognitive impairment) cannot be considered together with a group of disorders with a clear aetiology deriving from lesions of the central nervous system (brain injury) and with a functional status (physical inactivity), a risk factor for other pathologies.

Response 6: Thank you for your comment. The illnesses of rehabilitation were ranged based on hundreds of papers, they were all common symptoms in VR rehabilitation. The descriptions are in lines 64-67: "Virtual rehabilitation can be divided into different categories based on the types of conditions it aims to address: cognitive impairment, acquired brain damage, and physical inactivity".

Point 7: The research is applied to different conditions and not all are of a rehabilitative nature (i.e., physical inactivity in which virtual reality and other rehabilitative interventions are minimal).

Response 7: Thank you for your suggestion. We have do a great deal research and find that VR rehabilitation has been found to be effective in treating a range of conditions, including stroke, traumatic brain injury, spinal cord injury, amputations, and balance disorders. It can be used to improve motor function, balance, mobility, and cognitive function, as well as to reduce pain and anxiety. As a conclusion, it's too broad to look at just one symptom in a research.

Point 8: Then, the selection of the keywords is questionable. The use of a tool (the questionnaire) as mesh term could be a confounding factor due to a possible conditioning bias. 

Response 8: Thank you for your comment. We try to fully cover all kinds of symptoms in the description of patient statuses. The three keywords in the article are selected and classified.

Point 9: The used language is severely inefficient. The manuscript is quite fragmented with many elements all together continuously presented, without a logical and continuous articulation. Also, the written form is inadequate.

Response 9: We agree with your suggestion. We have made a more rigorous structural division, and the specific content is as follows：

1. Introduction 2. Material and Analysis   2.1 Search process     1）Source website     2）Search keywords     3）Brief introduction of the collected papers     4）Source database     5）Selection criteria     6）Risk of bias   2.2 Data analysis     1）Computation tools: StataSE and CMA     2）SNK-test (Q-test)     3）SMK (foster plot)     4）Pooled mean     5）Introduction of attributes 3. Results   3.1 Study identification     1）The process of selecting 26 papers from 607 papers in total   3.2 Study details     1）Data overview     2）Affiliation distribution     3）Publication venues, like Computer Science, Rehabilitation, etc.     4）Age of participants (and gender     5）Goal     6）Three important factors: demography, VR software, VR hardware     7）Briefly introduce each table and figure
    8）Risk of bias   3.3 Subject Characters and VR Cybersickness     1）Age factor and results     2）There are variations of symptom and condition     3）inducement circumstance   3.4 VR Software and Cybersickness     1）Time duration     2）4 contents: exercise games, training, videos, scenes   3.5 VR Hardware and Cybersickness     1）Locomotion     2）Control     3）Controller     4）Display type 4. Discussion   4.1 Demography of Cybersickness     1）Age leads to different levels, but in this paper it does not hold     2）Overall symptom         brain injuries         cognitive impairment         physical inactivity   4.2 Software Factors of Cybersickness     1）Exposure time     2）Four types of contents   4.3 Hardware Factors of Cybersickness     1）movements/locomotion     2）Control     3）Display type. 3DoF vs. 6DoF   4.4 Strengths, Limitations, and Future work 5. Conclusion     1）summary and value of this work     2）future directions

Point 10: Finally, it is good to report the changes tracked in the drafts of the manuscript, for fairness to the reviewer, in addition to the responses themselves.

Response 10: Thank you for the comment. The introduction of this paper is more detailed, the methods are more clearly classified, and the result part is also smoothly stated. The discussion is divided into three parts, and the conclusion part includes summary and future outlook. Even the references have been updated.

Point 11: The correct use of the methodology (PRISMA and systems of meta analysis) does not justify the conceptual bias that risks to provide altered results.

Response 11: Thank you for your reminder. The risk of bias is based on repeated statistics and confirmation. And it is mentioned in lines 257-261.

Lastly, we thank the reviewer again for reading our paper carefully and giving the above positive comments. About the English writing, we ask for native English speaker to revise the paper before it was submitted to the magazine at this time. I don’t know whether it has reached to your magazine’s standard.

Thank you very much. And best wishes!

Sincerely,

Dr Li

 

 

 

 

 

Author Response File: Author Response.pdf