The Current State of Virtual Reality in the Management of Musculoskeletal Conditions and Associated Chronic Pain: Terminology, Technology, and Associations
Carly Wender
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThis manuscript describes an overview of the current state of virtual reality (VR) in the healthcare field, specifically for persons with musculoskeletal conditions and chronic pain conditions. The authors first discuss the field wide issue of vague terminology and the ways in which that hinders VR from having been completely adopted in the healthcare sphere. The authors then propose a new framework to overcome such barriers. Finally, the authors summarize the current availability of hardware and software that could be utilized for different purposes in the healthcare sphere.
The authors take on a very important topic. It is clear that terminology is vague and that may limit our ability to use VR to its fullest potential in healthcare. However, I’m afraid that this publication ultimately adds more vagueness and complexity to the field rather than simplifying things. I think the goal of this manuscript is to make it easier for healthcare workers and providers to adopt effective VR tools for treatment. However, I don’t believe the manuscript as written accomplishes this goal. In short, it is unclear how the proposed framework shown in Figure 3b clarifies the use of VR in healthcare and helps providers use VR as a tool to help their patients.
Major Revisions:
1. There is no justification in the manuscript for the authors’ decision to focus on both musculoskeletal conditions and chronic pain. There are different ways in which VR would be applied to treatment for these conditions and there is major overlap in persons with musculoskeletal disorders and chronic pain. Is there enough evidence for the benefit of VR in the treatment of these conditions that it should be adopted in the healthcare space? References 5-10 (line 43) primarily points to VR for chronic pain rather than musculoskeletal disorders.
2. The authors talk a lot about the need for defining specific terms in VR to better facilitate translation of research into clinical care. In addition, the authors discuss how this vagueness in terminology has led to researchers being very specific in describing the characteristics of the VR they use (e.g., immersion, interaction). Can the authors clarify why unifying terminology is so important when it does not provide as much clarity as these specific characteristics of the VR?
3. The paragraphs on modern definitions of VR (lines 93-128) lacks focus and direction. There is no sense of understanding the history of VR and how it’s changed over time. In addition, the very basic definition of VR attributed to Ditchburn et al, 2020, actually stems from some original VR research done in the 1990’s (Ellis, 1991; Lombard et al., 1997).
a. Lines 124-125 state that the variety of VR applications signifies a lack of understanding of what VR is. Could an alternative explanation be that VR is a very broad term and these studies underly the myriad of ways that VR is being used to improve chronic pain and musculoskeletal rehabilitation? In that case, aren’t more specific descriptions of characteristics of what is being used advantageous for clinical providers looking to adopt a similar treatment tool?
4. The authors spend significant time discussing characteristics of VR including immersion and interaction. There is no mention of presence, which is highly important in VR and is comprised of characteristics including immersion and interaction. In addition, the authors hypothesize that there should be a clearer definition of immersion, but immersion is inherently subjective, based on individuals’ feelings of being in the virtual environment. Aside from HMDs in which immersion in very clear as the real world is occluded, feelings of immersion cannot be completely objective.
5. More justification is needed for a new proposed framework. How many previous frameworks have been proposed to unify terminology in this field? Why have they failed in doing so? How does this framework overcome those shortcomings? How does a newly proposed framework clarify the field rather than cause more confusion.
6. The proposed framework seems to suggest that non-immersive VR is not nearly as important or effective as immersive VR and should not be included in the definition of VR at all. Why does a distinction between immersive and non-immersive VR necessitate the need for such distinction in the definition? Non-immersive VR can still be effective for those with musculoskeletal disorders and chronic pain. This seems akin to exercise, in which aerobic and resistance exercise and distinct types of exercise with different effects on health outcomes. But both are still considered exercise. Why can’t immersive and non-immersive VR be classified similarly? What if it is unsafe for someone to wear an HMD and they would greatly benefit from non-immersive VR. Separating them so much might discourage healthcare providers from using non-immersive VR, despite the potential benefits.
7. Proposition 3 of the proposed framework does not appear to be based on any evidence from the field of VR at all. With this lack of data, is it perhaps too soon to propose this framework?
8. The proposed framework seems to focus primarily on immersive VR. Section 3 focuses entirely on immersive VR. Together, these suggest that the authors feel the evidence for the benefits of immersive VR far outweigh those of non-immersive VR. However, they have no used evidence in the field to make that compelling argument. Evidence clearly supports the benefits of immersive VR on pain over non-immersive VR because of greater presence and distraction, but this case has primarily been made for acute pain relief, not chronic pain relief. In addition, no such case has been made for musculoskeletal rehabilitation.
Minor Revisions:
1. Please differentiate musculoskeletal rehabilitation from neurological rehabilitation. Lines 34-38 suggest that VR has been more easily applicable in neurological rehabilitation rather than musculoskeletal rehabilitation because it’s use in improving motor function. However, musculoskeletal rehabilitation can also focus on motor function, depending on what a person is struggling with.
2. Please provide evidence for the statement that cost is a major barrier to healthcare adoptions of VR-based treatments (lines 38-41).
3. Second 2.1 would benefit from differentiating between industry and research. How much is XR actually used in research, despite its common use in industry?
4. The second paragraph of section 2.2 seems to discuss definitions of VR based on levels of immersion. But the examples the authors include all differ based on interaction, not immersion.
5. Please provide some evidence for the statement in lines 285-287. This point is pivotal to the entire argument of this paper around needing uniform terminology. However, it appears most research to date does a fairly good job describing the specific VR used, which would reduce the risk of this happening.
6. Figure 2: Is there evidence that people do not feel immersed or present when using wii games at all. A quick search found some research to suggest that presence is certainly lower than more immersive environments, but presence is not totally gone (Born et al., IEEE Xplore, 2019; Pallavicini et al., 2019)
7. Lines 469-470 state that the same software rarely appears in more than one study. Could this be due to the fact that most of this research is conducted by the tech companies themselves? This is an important point that should be included and considered in the discussion of bridging the gaps between research and clinical care.
Author Response
Dear Reviewer,
We sincerely thank you for your valuable comments and suggestions to improve our manuscript. We have carefully addressed all your comments and have provided detailed responses in the attached PDF document. We believe that the revised manuscript now meets the expectations of the journal and the review process.
Best regards, The authors
REVIEWER 1
This manuscript describes an overview of the current state of virtual reality (VR) in the healthcare field, specifically for persons with musculoskeletal conditions and chronic pain conditions. The authors first discuss the field wide issue of vague terminology and the ways in which that hinders VR from having been completely adopted in the healthcare sphere. The authors then propose a new framework to overcome such barriers. Finally, the authors summarize the current availability of hardware and software that could be utilized for different purposes in the healthcare sphere.
The authors take on a very important topic. It is clear that terminology is vague and that may limit our ability to use VR to its fullest potential in healthcare. However, I’m afraid that this publication ultimately adds more vagueness and complexity to the field rather than simplifying things. I think the goal of this manuscript is to make it easier for healthcare workers and providers to adopt effective VR tools for treatment. However, I don’t believe the manuscript as written accomplishes this goal. In short, it is unclear how the proposed framework shown in Figure 3b clarifies the use of VR in healthcare and helps providers use VR as a tool to help their patients.
RESPONSE: Thank you for your thoughtful feedback. We appreciate your recognition of the importance of addressing the challenges associated with vague VR terminology in the healthcare field and your acknowledgment of the manuscript’s focus on this critical topic. We understand your concerns and welcome the opportunity to clarify the purpose and goals of our work.
The primary aim of this manuscript is to address the inconsistencies in VR terminology that currently hinder communication in the healthcare field. While we agree that our proposed framework may initially introduce new concepts, our intention is not to complicate the field but to provide a foundation for standardizing VR terminology based on levels of immersion and technological characteristics. By distinguishing between non-immersive, semi-immersive, and immersive VR environments, we aim to reduce existing ambiguity and improve communication among researchers, healthcare providers, and developers.
To further clarify the practical application of the proposed framework, we have expanded Section 2.3 to include a detailed justification for its necessity, as outlined in our response to Comment 5.
Regarding Figure 3b, we acknowledge your concern and have added a detailed explanation in the manuscript to ensure its relevance and applicability to healthcare providers is clear.
We hope these revisions address your concerns and demonstrate how our proposed framework and recommendations aim to simplify, rather than complicate, the use of VR in healthcare. If there are further specific areas you believe require additional clarification, we would be happy to address them.
Major Revisions:
1. There is no justification in the manuscript for the authors’ decision to focus on both musculoskeletal conditions and chronic pain. There are different ways in which VR would be applied to treatment for these conditions and there is major overlap in persons with musculoskeletal disorders and chronic pain. Is there enough evidence for the benefit of VR in the treatment of these conditions that it should be adopted in the healthcare space? References 5-10 (line 43) primarily points to VR for chronic pain rather than musculoskeletal disorders.
RESPONSE: Thank you for your insightful feedback. We have revised the manuscript to address your concerns.
Throughout the manuscript, we have replaced the term “musculoskeletal conditions and chronic pain” with “musculoskeletal conditions and associated chronic pain” to clarify that the scope of the article is limited to musculoskeletal conditions, which may include chronic pain as a common feature. This distinction ensures that the focus is not extended to chronic pain originating from non-musculoskeletal (e.g., neurological) conditions.
To justify our decision to focus on musculoskeletal conditions regardless of chronicity, we have added a paragraph highlighting the psychosocial factors prevalent across both acute and chronic musculoskeletal conditions, which can be effectively and similarly addressed through VR. Additionally, we have included examples of how VR can be applied to the treatment of these conditions.
Below is the text that we added in Introduction (lines 46-63):
“In addition, for patients with these conditions, the use of VR goes beyond mere distraction from immediate pain. Recovery success in patients with musculoskeletal pain, regardless of chronicity, can be hindered by various psychosocial factors [7–13], which can be addressed through VR. VR can benefit patients with kinesiophobia by providing distraction from fear, which facilitates movement [14], or through gradual exposure to feared movements, enabling desensitization and reducing fear responses over time [15]. A fun, engaging, and interactive form of therapy is offered through VR, enhancing patient motivation for rehabilitation [16–18]. By enabling patients to develop skills for self-regulation of pain through interactive and sensory-augmented experiences, such as controlling unpleasant virtual elements via biosensor feedback or practicing deep breathing techniques in gamified environments, it also serves as a tool to improve self-efficacy [19]. Additionally, it facilitates embodiment, allowing users to perceive the virtual body as their own [20,21]. Consequently, during and after VR interventions, users exhibit attitudes or behaviors aligned with the characteristics of the virtual avatar, a phenomenon known as the Proteus effect [22,23]. By leveraging embodiment in virtual avatars, VR can help address altered body image [24,25], which is often particularly pronounced in cases of chronic pain [26] and can contribute to dysfunctional pain-coping strategies, such as movement avoidance [27].”
To address the concern regarding the focus of references, we have incorporated additional studies that demonstrate the effectiveness of VR across musculoskeletal conditions, not exclusively associated with chronic pain. These include: Elaraby et al. (2023) and Garcia Sanchez et al. (2023), that focus on orthopaedic ankle injuries and postoperative rehabilitation following total knee arthroplasty. We reformulated the text accordingly to reviewer’s comment (lines 63-66 in Introduction):
“Furthermore, meta-analyses have increasingly highlighted the significant benefits of VR in managing musculoskeletal conditions and associated chronic pain [26–34], underscoring its potential as a valuable tool for integration into healthcare to effectively address these conditions.”
2. The authors talk a lot about the need for defining specific terms in VR to better facilitate translation of research into clinical care. In addition, the authors discuss how this vagueness in terminology has led to researchers being very specific in describing the characteristics of the VR they use (e.g., immersion, interaction). Can the authors clarify why unifying terminology is so important when it does not provide as much clarity as these specific characteristics of the VR?
RESPONSE: Thank you for your feedback. In response, we have clarified the importance of unifying terminology in the manuscript. To address this, we have added the following explanation to the text (Section 2.2; lines 304-314):
“Overall, the inconsistency in VR terminology highlights the need for researchers and practitioners to precisely define the equipment and methods they use [38]. While detailed descriptions of interventions are valuable, the need for such precision can increase the risk of errors—if an intervention is not thoroughly described, reliance may fall solely on (potentially inaccurate) terminology. Different interpretations of the same terms can lead to the inclusion of various types of interventions under a single label. For example, in the case of non-immersive VR, it is currently unclear whether such environments require interaction from the user or not. Uniformity in terminology would facilitate clearer communication within the field by reducing the need for highly detailed descriptions of the technology used and its intended purpose, ensuring a shared understanding of key concepts.”
3. The paragraphs on modern definitions of VR (lines 93-128) lacks focus and direction. There is no sense of understanding the history of VR and how it’s changed over time. In addition, the very basic definition of VR attributed to Ditchburn et al, 2020, actually stems from some original VR research done in the 1990’s (Ellis, 1991; Lombard et al., 1997).
RESPONSE: Thank you for your comment. We have revised the section to provide a clearer narrative and include historical context.
To address the lack of historical context, we included references to early definitions of VR in the rehabilitation field from the 1990s (lines 129-132):
“Such a broader understanding may also stem from some of the earliest definitions in rehabilitation from the 1990s, which did not limit VR to immersive systems but described it as including HMDs as well as other equipment such as monitors or large screens [54,55].”
We have shortened and revised the section you mentioned (last paragraph of Section 2) to improve clarity. In this paragraph, our aim was to highlight the differences in VR definitions, focusing specifically on the field of healthcare, with a more focus on musculoskeletal rehabilitation. The intention of this section was not to provide a historical overview of VR terminology but rather to emphasize the aspects in which definitions differ and explore the possible reasons for these differences.
a. Lines 124-125 state that the variety of VR applications signifies a lack of understanding of what VR is. Could an alternative explanation be that VR is a very broad term and these studies underly the myriad of ways that VR is being used to improve chronic pain and musculoskeletal rehabilitation? In that case, aren’t more specific descriptions of characteristics of what is being used advantageous for clinical providers looking to adopt a similar treatment tool?
RESPONSE: In response to the comment, we have added an alternative explanation that VR can be considered a very broad term in the field of healthcare (Lines 127-135):
“This discrepancy indicates that VR in healthcare encompasses a broad spectrum of technologies and that VR remains a very broad term in this field. Such a broader understanding may also stem from some of the earliest definitions in rehabilitation from the 1990s, which did not limit VR to immersive systems but described it as including HMDs as well as other equipment such as monitors or large screens [56,57]. On the other hand, the inconsistency in reported definitions poses significant challenges. These inconsistencies limit the understanding and applicability of research findings, restrict researchers from identifying relevant studies, and raise unrealistic expectations about the potential of these novel solutions [40,58].”
We agree that precise descriptions of interventions are necessary. However, we believe that the lack of clarity in definitions also introduces certain risks, which we have highlighted in the text and addressed in our response to Comment 2 from Reviewer 1.
4. The authors spend significant time discussing characteristics of VR including immersion and interaction. There is no mention of presence, which is highly important in VR and is comprised of characteristics including immersion and interaction. In addition, the authors hypothesize that there should be a clearer definition of immersion, but immersion is inherently subjective, based on individuals’ feelings of being in the virtual environment. Aside from HMDs in which immersion in very clear as the real world is occluded, feelings of immersion cannot be completely objective.
RESPONSE: Thank you for your thoughtful comment. We would like to clarify why the term presence does not appear in the sections where we discuss the current state of VR definitions. Specifically, we did not encounter the term presence in the definitions of VR commonly found in healthcare literature. As a result, definitions incorporating presence are not presented in the early sections of the manuscript (e.g., Sections 2, 2.1, and 2.2).
However, we agree that presence is a crucial concept in VR terminology. In light of your comment, we have added a discussion on presence to Section 2.3, where we address its importance and its relationship with immersion (lines 417-424):
»A higher number of stimulated senses enhances immersion and, consequently, the sense of presence by increasing the feeling of "being there” [83]. This occurs because more attentional resources are allocated to the virtual world as the number of stimulated senses increases [83]. The level of immersion increases not only with the number of virtually stimulated senses but also with the quality of virtual stimulation. The better the quality of virtual stimuli (e.g., the visual appearance of objects, tracking quality, etc.), the greater the immersion. This, in turn, contributes to higher perceived realism and subsequently enhances the sense of presence [83].«
Regarding the second part of your comment, we respectfully disagree with the assertion that immersion is inherently subjective. Based on our review of recent literature, immersion is typically described as an objective quality of VR, primarily determined by the technological capabilities of the system. In contrast, sense of presence refers to the subjective experience of being in the virtual environment. To further support this distinction, we reference Wilkinson et al. (2021), who conducted a review on the concepts of presence and immersion. Their findings clearly differentiate between the two:
»On the other hand, immersion is associated with the more technical aspect related to the illusion. It is a more objective quality of VR insofar as the technology is capable of providing realistic feedback, general interaction, and its ability to allow the user to move and behave as they would normally (Table 2). The thematic content analysis revealed two themes: presence is experiential, immersion is the technical qualities of a system that aide the feeling of presence.«
We believe these clarifications and the addition of the discussion on presence in Section 2.3 address your concerns and enhance the manuscript.
5. More justification is needed for a new proposed framework. How many previous frameworks have been proposed to unify terminology in this field? Why have they failed in doing so? How does this framework overcome those shortcomings? How does a newly proposed framework clarify the field rather than cause more confusion.
RESPONSE: Thank you for your comment. The frameworks we identified are discussed in Section 2.1 and presented in Figure 1. In the healthcare field, we found only one article by Abbas et al. (2023) that specifically addresses VR terminology in this domain (presented in Section 2.1; lines 202-208). To our knowledge, publication by Abbas et al., (2023) is the only publication attempting to define VR terminology for healthcare applications comprehensively.
The definition of VR proposed by Abbas et al. (2023) was designed to accommodate the existing confusion in the field and to encompass the broad range of interpretations of what
constitutes VR. Abbas et al. (2023) did not address the confusion surrounding the understanding of computer-generated environments offering varying levels of immersion, but instead tailored their definition to reflect the current ambiguity in the field. In contrast, our approach focuses on clarifying what VR means, with an emphasis on understanding computer-generated environments with varying levels of immersion.
We believe there is significant confusion regarding what constitutes different levels of immersion in VR environments, particularly in defining non-immersive and semi-immersive VR. Meanwhile, current definitions of immersive VR are often limited solely to the use of HMD headsets, overlooking other modern technologies that stimulate additional exteroceptive senses (as presented in Chapter 2.2). Additionally, there also appears to be confusion about whether VR is understood as an immersive environment or as an environment that can encompass various levels of immersion. This lack of clarity underscores the need to develop a more refined framework specifically addressing the concept of immersion. To the best of our knowledge, our proposed framework is the first in the healthcare field to tackle this issue comprehensively.
We do not believe that our framework introduces further confusion. On the contrary, it aims to address the existing lack of clarity regarding the definitions of non-immersive, immersive, and semi-immersive VR, as discussed in Section 2.2. Our article serves as a starting point for establishing uniform terminology in this field, which appears to urgently require a standardized approach. We believe it will contribute to reducing ambiguity and facilitating clearer communication within the field.
To address the reviewer's concerns, we have added the following justification to our article:
Section 2.1. (lines 206-208):
“Accordingly, in their literature review, Abbas et al., (2023) examined how the term VR is defined in the medical literature and proposed the following definition of VR: “VR is a three-dimensional computer-generated simulated environment, which attempts to replicate real-world or imaginary environments and interactions, thereby supporting work, education, recreation, and health.”. Their definition was constructed to accommodate the current confusion in the field and to encompass the broad range of interpretations of what constitutes VR.”
Section 2.3 (lines 317-334):
“The terminology surrounding VR in healthcare is characterized by inconsistency and ambiguity, particularly regarding levels of immersion. While Abbas et al. (2023) provided a comprehensive attempt to define VR terminology for healthcare applications, their approach primarily aimed to accommodate the existing confusion in the field, rather than resolve it by addressing the ambiguity surrounding terms like non-immersive, semi-immersive, and immersive VR. We believe there is significant confusion regarding what constitutes different levels of immersion in VR environments, particularly in defining non-immersive and semi-immersive VR. Meanwhile, current definitions of immersive VR are often limited solely to the use of HMD head-sets, overlooking other modern technologies that stimulate additional exteroceptive senses (as presented in Chapter 2.2). Additionally, there also appears to be confusion about whether VR is understood as an immersive environment or as an environment that can encompass various levels of immersion. This lack of clarity underscores the need to develop a more refined framework specifically addressing the concept of immersion. To the best of our knowledge, our proposed framework is the first in the healthcare field to tackle this issue comprehensively. Our article serves as a starting point for establishing uniform terminology in this field, which appears to urgently require a standardized approach. We believe it will contribute to reducing ambiguity and facilitating clearer communication within the field.”
6. The proposed framework seems to suggest that non-immersive VR is not nearly as important or effective as immersive VR and should not be included in the definition of VR at all. Why does a distinction between immersive and non-immersive VR necessitate the need for such distinction in the definition? Non-immersive VR can still be effective for those with musculoskeletal disorders and chronic pain. This seems akin to exercise, in which aerobic and resistance exercise and distinct types of exercise with different effects on health outcomes. But both are still considered exercise. Why can’t immersive and non-immersive VR be classified similarly? What if it is unsafe for someone to wear an HMD and they would greatly benefit from non-immersive VR. Separating them so much might discourage healthcare providers from using non-immersive VR, despite the potential benefits.
RESPONSE: Thank you for your comment. Our article does not aim to compare VR environments based on their effectiveness. Instead, it focuses on addressing terminological challenges in the field. We agree that it would be misleading to suggest that our proposed terminology is based on the effectiveness of specific technological solutions. To avoid any such misunderstanding, we have removed the following sentence from Proposition 2:
“Evidence from healthcare further supports the validity of this distinction, with studies demonstrating that immersive and non-immersive experiences have varying effects [77,78].”
Additionally, we reviewed the entire manuscript to ensure that no statements imply a comparison of the effects of different VR environments. This is to avoid conveying the incorrect message that the separation of non-immersive VR environments from VR is based on differences in their effectiveness.
Our distinction between non-immersive and immersive VR environments is solely based on the equipment used and the technological solutions they provide. As explained in our response to Comment 4, immersiveness is a technical attribute of the system. We agree with authors who define VR as inherently immersive (see lines 116-118), and for this reason, we have separated non-immersive environments from VR. To our knowledge, this is the first attempt to clearly define what constitutes non-immersive environments versus immersive VR.
This separation is not intended to discourage the use of non-immersive environments in healthcare but rather to establish a clear and standardized framework for understanding and categorizing VR technologies based on their technical characteristics. We believe this distinction will facilitate more precise communication within the field and support the effective implementation of both immersive and non-immersive technologies in clinical practice.
To clarify this in the article, we have added the following text to Proposition 2 (lines 367-377):
“We would like to emphasize that this distinction is not based on differences in the effectiveness of non-immersive and immersive environments. The separation of non-immersive environments is made based on the technological solutions these envi-ronments offer compared to immersive ones. As presented in the review article by Wilkinson et al., (2021) immersion is described as "a more objective quality of VR" and "the technical qualities of a system". Furthermore, this distinction aligns with certain proposals from other authors in the field who also define VR as exclusively immersive environments [44,46,47]. This separation is not intended to discourage the use of non-immersive environments in healthcare but rather to establish a clear and standardized framework for under-standing and categorizing VR technologies based on their technical characteristics.”
7. Proposition 3 of the proposed framework does not appear to be based on any evidence from the field of VR at all. With this lack of data, is it perhaps too soon to propose this framework?
RESPONSE: Thank you for your comment. To address the reviewer’s concern, we have added a reference to Proposition 3 that describes the use of interoception stimulation in conjunction with VR in the medical field (see lines 405-410):
“To the best of our knowledge, no research in the healthcare field has yet combined VR with interoception stimulation. However, there are articles that discuss the integration of internal body stimulation with VR in the medical field [83], highlighting the need to reconceptualize certain previous frameworks that suggested interoception stimulation with modern technology was not possible [39].”
Since our article primarily focuses on the terminology and understanding of concepts related to VR, we believe it is appropriate to also highlight emerging areas, such as interoception stimulation, even though research in this domain is still limited. With the proposed framework, we aim to encompass all possibilities that VR currently offers, regardless of the number of studies available in this field. We also want to emphasize the possibility of interoception stimulation, as previous proposed frameworks stated that internal body stimulation was not possible.
8. The proposed framework seems to focus primarily on immersive VR. Section 3 focuses entirely on immersive VR. Together, these suggest that the authors feel the evidence for the benefits of immersive VR far outweigh those of non-immersive VR. However, they have no used evidence in the field to make that compelling argument. Evidence clearly supports the benefits of immersive VR on pain over non-immersive VR because of greater presence and distraction, but this case has primarily been made for acute pain relief, not chronic pain relief. In addition, no such case has been made for musculoskeletal rehabilitation.
RESPONSE: Thank you for your comment. We appreciate the opportunity to clarify our intentions. Our proposed framework and article do not aim to prioritize immersive VR over non-immersive VR or suggest that immersive VR is inherently more beneficial. Instead, our primary focus is on addressing terminological challenges and providing a standardized framework for understanding and categorizing VR technologies based on their technical characteristics.
To ensure this point is clear, we reviewed Section 3 and the rest of the manuscript to verify that no content implies a direct comparison between the benefits of immersive and non-immersive VR. Our framework is not intended to advocate for one type of VR over another. Instead, it seeks to provide clarity on what constitutes immersive and non-immersive environments, which is essential for interpreting evidence and facilitating communication in the field.
To address this concern explicitly in the article, we have added the following clarification to Section 2.3 (see lines 334-338):
“Our framework is not intended to prioritize immersive VR over non-immersive VR or to suggest that one is inherently more beneficial than the other. Instead, it seeks to address existing terminological inconsistencies and provide a standardized basis for understanding VR environments based on their technical characteristics.”
We hope this addition and clarification address your concerns and demonstrate the scope and intent of our framework.
Minor Revisions:
1. Please differentiate musculoskeletal rehabilitation from neurological rehabilitation. Lines 34-38 suggest that VR has been more easily applicable in neurological rehabilitation rather than musculoskeletal rehabilitation because it’s use in improving motor function. However, musculoskeletal rehabilitation can also focus on motor function, depending on what a person is struggling with.
RESPONSE: We appreciate this observation and have revised the text to clarify the differences between musculoskeletal and neurological rehabilitation. In the updated manuscript, we now explicitly acknowledge that motor function improvement is a key focus in both fields. However, we also highlight the differing primary objectives: while neurological rehabilitation often centers on facilitating cortical reorganization and restoring motor control after neural injury, musculoskeletal rehabilitation typically emphasizes goals such as improving range of motion, increasing muscle strength, and managing pain. These distinctions have been integrated into the revised introduction to provide a clearer differentiation.
Updated text (lines 38-40):
“Although motor function improvement is also an important focus in musculoskeletal rehabilitation, the field often emphasizes goals such as enhancing range of motion, increasing muscle strength, and managing pain.”
2. Please provide evidence for the statement that cost is a major barrier to healthcare adoptions of VR-based treatments (lines 38-41).
RESPONSE: Thank you for pointing this out. To address this comment, we have provided evidence supporting the claim that financial costs are a significant barrier to the implementation of VR in healthcare. We have cited a recent scoping review that specifically identifies financial costs as a notable challenge in adopting VR-based treatments. Additionally, we included evidence indicating that VR may, in fact, be cost-saving for managing chronic musculoskeletal conditions, providing a balanced perspective.
Updated text (lines 40-46):
“At first glance, it may seem that these objectives would not significantly benefit from VR compared to traditional non-VR interventions, raising questions about its cost-effectiveness for widespread adoption in the musculoskeletal field. Accordingly, a recent scoping review identified financial costs as one of the barriers to the implementation of VR in healthcare [5]. However, it appears that in the field of chronic musculoskeletal conditions, VR may be cost-saving compared to non-VR interventions [6].”
3. Second 2.1 would benefit from differentiating between industry and research. How much is XR actually used in research, despite its common use in industry?
RESPONSE: In response to your comment, we have revised Section 2.1 to better differentiate between the use of XR in industry and research. Specifically, we have added a discussion highlighting that, while XR technologies are frequently used in industry for training, simulations, and entertainment—often emphasizing more immersive technologies—applications in healthcare tend to rely more on non-immersive approaches.
Below, we have included the text added to Section 2.1 (lines 215-223):
“One possible explanation for this discrepancy is the frequent use of various types of XR technologies in industry, particularly for training, simulations, and entertainment, where more immersive technologies often take center stage. In contrast, applications in healthcare tend to rely more on non-immersive approaches, such as Nintendo Wii games, a technology whose production in the industry ended in 2013. When it comes to immersive experiences, healthcare primarily utilizes immersive VR, while the use of MR and AR currently lags behind. This is likely due to the increasing accessibility of immersive VR, whereas MR and AR remain relatively recent developments.”
4. The second paragraph of section 2.2 seems to discuss definitions of VR based on levels of immersion. But the examples the authors include all differ based on interaction, not immersion.
RESPONSE: Thank you for your observation. In Section 2.2, our goal was to present definitions commonly found in healthcare literature for terms such as "non-immersive VR," "semi-immersive VR," and "immersive VR." While these definitions primarily focus on levels of immersion, they also reveal differences in how interaction is conceptualized. For example, some definitions describe "non-immersive" environments as interactive, while others do not.
Our intention was not to define the differences between interactive and non-interactive VR environments. Instead, our goal was to present the current understanding of what constitutes "non-immersive VR," "immersive VR," and "semi-immersive VR." This understanding evidently varies, including differences in the types of interaction described within these environments.
We hope this clarification addresses your concern.
5. Please provide some evidence for the statement in lines 285-287. This point is pivotal to the entire argument of this paper around needing uniform terminology. However, it appears most research to date does a fairly good job describing the specific VR used, which would reduce the risk of this happening.
RESPONSE: In response to Comment 2 (in major revisions), we removed the statement referenced in lines 285–287 and rephrased the text accordingly (please see our response to Comment 2 for details). In that response, we also provided additional clarification on why the need for uniform terminology persists.
While we agree that providing a precise description of the equipment and use of VR is essential, we believe that the lack of consistency in understanding terms such as non-immersive, immersive, and semi-immersive VR underscores the continued importance of establishing uniform terminology. This would help ensure clearer communication and reduce potential misunderstandings across the field.
6. Figure 2: Is there evidence that people do not feel immersed or present when using wii games at all. A quick search found some research to suggest that presence is certainly lower than more immersive environments, but presence is not totally gone (Born et al., IEEE Xplore, 2019; Pallavicini et al., 2019)
RESPONSE: Since immersion primarily refers to the objective technological aspects of an environment, as discussed in our response to Reviewer Comment 4 (in major revisions), we believe that the term "non-immersive VR" is an appropriate name for environments where the technology does not allow for full visual immersion. Non-immersive environments are thus defined based on the technological capabilities rather than the subjective sense of presence.
We do not claim that the sense of being there or perceived realism is impossible in non-immersive environments. Rather, we distinguish non-immersive from immersive environments based on the technology used. Therefore, we believe the term "non-immersive" for environments that do not enable complete visual immersion is appropriate and not contradictory to evidence suggesting that a sense of presence is achievable even in non-immersive environments.
To better clarify this, we have added the following text to the article in Proposition 2 (line 355 and 363-366):
“For VR in healthcare currently labeled as "non-immersive," which typically involves the projection of artificial environments on a computer or television screen (e.g., Wii games) and does not allow for complete visual detachment from the real world, regardless of whether these environments are interactive or non-interactive, we propose the term "non-immersive fully artificial environments".”
“Non-immersive fully artificial environments can still provide a certain degree of presence[79]. However, since the technology used in these environments does not allow for complete visual detachment from the real world, we categorize them as non-immersive environments.”
7. Lines 469-470 state that the same software rarely appears in more than one study. Could this be due to the fact that most of this research is conducted by the tech companies themselves? This is an important point that should be included and considered in the discussion of bridging the gaps between research and clinical care.
RESPONSE: To address the reviewer’s comment, we have added the following sentence to the text (lines 533-535):
“This variability could be attributed, at least in part, to the possibility that some of this research is funded by technology companies developing proprietary VR systems [128].”
We also reviewed studies in the field of musculoskeletal rehabilitation that investigate the use of immersive VR and found only one study (Garcia et al., 2021) that was funded by a technology company (Applied VR). Therefore, we did not include a more extensive discussion on this topic in the article.
REVIEWER 2
The work is well done, the analysis collects in my opinion the main aspects to take into consideration in this field and the narration is well conducted. The references are appropriate both in number and selection, the graphic part is clear and well understandable by the reader, the results stimulating for the reader.
RESPONSE: Thank you for your kind and encouraging feedback. We are delighted that you found our work well-conducted, with a comprehensive analysis and appropriate references. We are also pleased that the graphical elements were clear and that the results were stimulating for the reader.
REVIEWER 3
In the academic editor notes, you stated that the revisions should address the overall comments from Reviewer 1 and the specific comments from Reviewer 3 regarding the discussion and conclusion. Therefore, only the comments related to the discussion and conclusion are provided below.
Discussion
There is no critical analysis of the studies included in the review.
The discussion does not explore how the findings could be directly applied in rehabilitation settings.
Often, the discussion seems disconnected from the challenges mentioned in the introduction and the results presented.
RESPONSE: Thank you for your comment. Since the reviewer has indicated that these comments pertain to the discussion, and our article does not include a section specifically titled "Discussion," we are unsure about the exact revisions being requested. However, we believe that we have addressed the concerns raised through revisions made in response to comments from Reviewer 1.
For instance, we expanded the justification for our proposed framework in Section 2.3 (please see our response to Comment 5 from Reviewer 1 in major revisions). Additionally, in the final paragraph of the introduction, we explicitly describe how our findings can contribute to clinical practice.
If there are further specific areas the reviewer would like us to address, we would be happy to provide additional clarification.
Conclusion
The conclusion provides a general summary of challenges and opportunities but does not include specific recommendations for professionals or researchers.
No concrete steps are proposed to address identified gaps, such as the need to standardise terminology or develop specialised software.
RESPONSE: Thank you for your comment. To address your concerns, we have revised the conclusion to include specific recommendations, particularly regarding the development of software solutions (lines 700-701):
“Current software solutions often fail to leverage VR's full potential mechanisms, such as its impact on kinesiophobia and body image through the use of body illusions or body-swapping techniques, highlighting the need for the development of additional software solutions in the field of musculoskeletal rehabilitation.”
Additionally, we have addressed the need for standardized terminology in Section 2.3, where we provide a detailed justification for this requirement. This is also outlined in our response to Comment 5 from Reviewer 1 (in major revisions).
We hope these additions clarify our intentions and provide concrete steps to address the identified gaps.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe work is well done, the analysis collects in my opinion the main aspects to take into consideration in this field and the narration is well conducted. The references are appropriate both in number and selection, the graphic part is clear and well understandable by the reader, the results stimulating for the reader.
Author Response
Dear Reviewer,
We sincerely thank you for your valuable comments and suggestions to improve our manuscript. We have carefully addressed all your comments and have provided detailed responses in the attached PDF document. We believe that the revised manuscript now meets the expectations of the journal and the review process.
Best regards, The authors
REVIEWER 1
This manuscript describes an overview of the current state of virtual reality (VR) in the healthcare field, specifically for persons with musculoskeletal conditions and chronic pain conditions. The authors first discuss the field wide issue of vague terminology and the ways in which that hinders VR from having been completely adopted in the healthcare sphere. The authors then propose a new framework to overcome such barriers. Finally, the authors summarize the current availability of hardware and software that could be utilized for different purposes in the healthcare sphere.
The authors take on a very important topic. It is clear that terminology is vague and that may limit our ability to use VR to its fullest potential in healthcare. However, I’m afraid that this publication ultimately adds more vagueness and complexity to the field rather than simplifying things. I think the goal of this manuscript is to make it easier for healthcare workers and providers to adopt effective VR tools for treatment. However, I don’t believe the manuscript as written accomplishes this goal. In short, it is unclear how the proposed framework shown in Figure 3b clarifies the use of VR in healthcare and helps providers use VR as a tool to help their patients.
RESPONSE: Thank you for your thoughtful feedback. We appreciate your recognition of the importance of addressing the challenges associated with vague VR terminology in the healthcare field and your acknowledgment of the manuscript’s focus on this critical topic. We understand your concerns and welcome the opportunity to clarify the purpose and goals of our work.
The primary aim of this manuscript is to address the inconsistencies in VR terminology that currently hinder communication in the healthcare field. While we agree that our proposed framework may initially introduce new concepts, our intention is not to complicate the field but to provide a foundation for standardizing VR terminology based on levels of immersion and technological characteristics. By distinguishing between non-immersive, semi-immersive, and immersive VR environments, we aim to reduce existing ambiguity and improve communication among researchers, healthcare providers, and developers.
To further clarify the practical application of the proposed framework, we have expanded Section 2.3 to include a detailed justification for its necessity, as outlined in our response to Comment 5.
Regarding Figure 3b, we acknowledge your concern and have added a detailed explanation in the manuscript to ensure its relevance and applicability to healthcare providers is clear.
We hope these revisions address your concerns and demonstrate how our proposed framework and recommendations aim to simplify, rather than complicate, the use of VR in healthcare. If there are further specific areas you believe require additional clarification, we would be happy to address them.
Major Revisions:
1. There is no justification in the manuscript for the authors’ decision to focus on both musculoskeletal conditions and chronic pain. There are different ways in which VR would be applied to treatment for these conditions and there is major overlap in persons with musculoskeletal disorders and chronic pain. Is there enough evidence for the benefit of VR in the treatment of these conditions that it should be adopted in the healthcare space? References 5-10 (line 43) primarily points to VR for chronic pain rather than musculoskeletal disorders.
RESPONSE: Thank you for your insightful feedback. We have revised the manuscript to address your concerns.
Throughout the manuscript, we have replaced the term “musculoskeletal conditions and chronic pain” with “musculoskeletal conditions and associated chronic pain” to clarify that the scope of the article is limited to musculoskeletal conditions, which may include chronic pain as a common feature. This distinction ensures that the focus is not extended to chronic pain originating from non-musculoskeletal (e.g., neurological) conditions.
To justify our decision to focus on musculoskeletal conditions regardless of chronicity, we have added a paragraph highlighting the psychosocial factors prevalent across both acute and chronic musculoskeletal conditions, which can be effectively and similarly addressed through VR. Additionally, we have included examples of how VR can be applied to the treatment of these conditions.
Below is the text that we added in Introduction (lines 46-63):
“In addition, for patients with these conditions, the use of VR goes beyond mere distraction from immediate pain. Recovery success in patients with musculoskeletal pain, regardless of chronicity, can be hindered by various psychosocial factors [7–13], which can be addressed through VR. VR can benefit patients with kinesiophobia by providing distraction from fear, which facilitates movement [14], or through gradual exposure to feared movements, enabling desensitization and reducing fear responses over time [15]. A fun, engaging, and interactive form of therapy is offered through VR, enhancing patient motivation for rehabilitation [16–18]. By enabling patients to develop skills for self-regulation of pain through interactive and sensory-augmented experiences, such as controlling unpleasant virtual elements via biosensor feedback or practicing deep breathing techniques in gamified environments, it also serves as a tool to improve self-efficacy [19]. Additionally, it facilitates embodiment, allowing users to perceive the virtual body as their own [20,21]. Consequently, during and after VR interventions, users exhibit attitudes or behaviors aligned with the characteristics of the virtual avatar, a phenomenon known as the Proteus effect [22,23]. By leveraging embodiment in virtual avatars, VR can help address altered body image [24,25], which is often particularly pronounced in cases of chronic pain [26] and can contribute to dysfunctional pain-coping strategies, such as movement avoidance [27].”
To address the concern regarding the focus of references, we have incorporated additional studies that demonstrate the effectiveness of VR across musculoskeletal conditions, not exclusively associated with chronic pain. These include: Elaraby et al. (2023) and Garcia Sanchez et al. (2023), that focus on orthopaedic ankle injuries and postoperative rehabilitation following total knee arthroplasty. We reformulated the text accordingly to reviewer’s comment (lines 63-66 in Introduction):
“Furthermore, meta-analyses have increasingly highlighted the significant benefits of VR in managing musculoskeletal conditions and associated chronic pain [26–34], underscoring its potential as a valuable tool for integration into healthcare to effectively address these conditions.”
2. The authors talk a lot about the need for defining specific terms in VR to better facilitate translation of research into clinical care. In addition, the authors discuss how this vagueness in terminology has led to researchers being very specific in describing the characteristics of the VR they use (e.g., immersion, interaction). Can the authors clarify why unifying terminology is so important when it does not provide as much clarity as these specific characteristics of the VR?
RESPONSE: Thank you for your feedback. In response, we have clarified the importance of unifying terminology in the manuscript. To address this, we have added the following explanation to the text (Section 2.2; lines 304-314):
“Overall, the inconsistency in VR terminology highlights the need for researchers and practitioners to precisely define the equipment and methods they use [38]. While detailed descriptions of interventions are valuable, the need for such precision can increase the risk of errors—if an intervention is not thoroughly described, reliance may fall solely on (potentially inaccurate) terminology. Different interpretations of the same terms can lead to the inclusion of various types of interventions under a single label. For example, in the case of non-immersive VR, it is currently unclear whether such environments require interaction from the user or not. Uniformity in terminology would facilitate clearer communication within the field by reducing the need for highly detailed descriptions of the technology used and its intended purpose, ensuring a shared understanding of key concepts.”
3. The paragraphs on modern definitions of VR (lines 93-128) lacks focus and direction. There is no sense of understanding the history of VR and how it’s changed over time. In addition, the very basic definition of VR attributed to Ditchburn et al, 2020, actually stems from some original VR research done in the 1990’s (Ellis, 1991; Lombard et al., 1997).
RESPONSE: Thank you for your comment. We have revised the section to provide a clearer narrative and include historical context.
To address the lack of historical context, we included references to early definitions of VR in the rehabilitation field from the 1990s (lines 129-132):
“Such a broader understanding may also stem from some of the earliest definitions in rehabilitation from the 1990s, which did not limit VR to immersive systems but described it as including HMDs as well as other equipment such as monitors or large screens [54,55].”
We have shortened and revised the section you mentioned (last paragraph of Section 2) to improve clarity. In this paragraph, our aim was to highlight the differences in VR definitions, focusing specifically on the field of healthcare, with a more focus on musculoskeletal rehabilitation. The intention of this section was not to provide a historical overview of VR terminology but rather to emphasize the aspects in which definitions differ and explore the possible reasons for these differences.
a. Lines 124-125 state that the variety of VR applications signifies a lack of understanding of what VR is. Could an alternative explanation be that VR is a very broad term and these studies underly the myriad of ways that VR is being used to improve chronic pain and musculoskeletal rehabilitation? In that case, aren’t more specific descriptions of characteristics of what is being used advantageous for clinical providers looking to adopt a similar treatment tool?
RESPONSE: In response to the comment, we have added an alternative explanation that VR can be considered a very broad term in the field of healthcare (Lines 127-135):
“This discrepancy indicates that VR in healthcare encompasses a broad spectrum of technologies and that VR remains a very broad term in this field. Such a broader understanding may also stem from some of the earliest definitions in rehabilitation from the 1990s, which did not limit VR to immersive systems but described it as including HMDs as well as other equipment such as monitors or large screens [56,57]. On the other hand, the inconsistency in reported definitions poses significant challenges. These inconsistencies limit the understanding and applicability of research findings, restrict researchers from identifying relevant studies, and raise unrealistic expectations about the potential of these novel solutions [40,58].”
We agree that precise descriptions of interventions are necessary. However, we believe that the lack of clarity in definitions also introduces certain risks, which we have highlighted in the text and addressed in our response to Comment 2 from Reviewer 1.
4. The authors spend significant time discussing characteristics of VR including immersion and interaction. There is no mention of presence, which is highly important in VR and is comprised of characteristics including immersion and interaction. In addition, the authors hypothesize that there should be a clearer definition of immersion, but immersion is inherently subjective, based on individuals’ feelings of being in the virtual environment. Aside from HMDs in which immersion in very clear as the real world is occluded, feelings of immersion cannot be completely objective.
RESPONSE: Thank you for your thoughtful comment. We would like to clarify why the term presence does not appear in the sections where we discuss the current state of VR definitions. Specifically, we did not encounter the term presence in the definitions of VR commonly found in healthcare literature. As a result, definitions incorporating presence are not presented in the early sections of the manuscript (e.g., Sections 2, 2.1, and 2.2).
However, we agree that presence is a crucial concept in VR terminology. In light of your comment, we have added a discussion on presence to Section 2.3, where we address its importance and its relationship with immersion (lines 417-424):
»A higher number of stimulated senses enhances immersion and, consequently, the sense of presence by increasing the feeling of "being there” [83]. This occurs because more attentional resources are allocated to the virtual world as the number of stimulated senses increases [83]. The level of immersion increases not only with the number of virtually stimulated senses but also with the quality of virtual stimulation. The better the quality of virtual stimuli (e.g., the visual appearance of objects, tracking quality, etc.), the greater the immersion. This, in turn, contributes to higher perceived realism and subsequently enhances the sense of presence [83].«
Regarding the second part of your comment, we respectfully disagree with the assertion that immersion is inherently subjective. Based on our review of recent literature, immersion is typically described as an objective quality of VR, primarily determined by the technological capabilities of the system. In contrast, sense of presence refers to the subjective experience of being in the virtual environment. To further support this distinction, we reference Wilkinson et al. (2021), who conducted a review on the concepts of presence and immersion. Their findings clearly differentiate between the two:
»On the other hand, immersion is associated with the more technical aspect related to the illusion. It is a more objective quality of VR insofar as the technology is capable of providing realistic feedback, general interaction, and its ability to allow the user to move and behave as they would normally (Table 2). The thematic content analysis revealed two themes: presence is experiential, immersion is the technical qualities of a system that aide the feeling of presence.«
We believe these clarifications and the addition of the discussion on presence in Section 2.3 address your concerns and enhance the manuscript.
5. More justification is needed for a new proposed framework. How many previous frameworks have been proposed to unify terminology in this field? Why have they failed in doing so? How does this framework overcome those shortcomings? How does a newly proposed framework clarify the field rather than cause more confusion.
RESPONSE: Thank you for your comment. The frameworks we identified are discussed in Section 2.1 and presented in Figure 1. In the healthcare field, we found only one article by Abbas et al. (2023) that specifically addresses VR terminology in this domain (presented in Section 2.1; lines 202-208). To our knowledge, publication by Abbas et al., (2023) is the only publication attempting to define VR terminology for healthcare applications comprehensively.
The definition of VR proposed by Abbas et al. (2023) was designed to accommodate the existing confusion in the field and to encompass the broad range of interpretations of what
constitutes VR. Abbas et al. (2023) did not address the confusion surrounding the understanding of computer-generated environments offering varying levels of immersion, but instead tailored their definition to reflect the current ambiguity in the field. In contrast, our approach focuses on clarifying what VR means, with an emphasis on understanding computer-generated environments with varying levels of immersion.
We believe there is significant confusion regarding what constitutes different levels of immersion in VR environments, particularly in defining non-immersive and semi-immersive VR. Meanwhile, current definitions of immersive VR are often limited solely to the use of HMD headsets, overlooking other modern technologies that stimulate additional exteroceptive senses (as presented in Chapter 2.2). Additionally, there also appears to be confusion about whether VR is understood as an immersive environment or as an environment that can encompass various levels of immersion. This lack of clarity underscores the need to develop a more refined framework specifically addressing the concept of immersion. To the best of our knowledge, our proposed framework is the first in the healthcare field to tackle this issue comprehensively.
We do not believe that our framework introduces further confusion. On the contrary, it aims to address the existing lack of clarity regarding the definitions of non-immersive, immersive, and semi-immersive VR, as discussed in Section 2.2. Our article serves as a starting point for establishing uniform terminology in this field, which appears to urgently require a standardized approach. We believe it will contribute to reducing ambiguity and facilitating clearer communication within the field.
To address the reviewer's concerns, we have added the following justification to our article:
Section 2.1. (lines 206-208):
“Accordingly, in their literature review, Abbas et al., (2023) examined how the term VR is defined in the medical literature and proposed the following definition of VR: “VR is a three-dimensional computer-generated simulated environment, which attempts to replicate real-world or imaginary environments and interactions, thereby supporting work, education, recreation, and health.”. Their definition was constructed to accommodate the current confusion in the field and to encompass the broad range of interpretations of what constitutes VR.”
Section 2.3 (lines 317-334):
“The terminology surrounding VR in healthcare is characterized by inconsistency and ambiguity, particularly regarding levels of immersion. While Abbas et al. (2023) provided a comprehensive attempt to define VR terminology for healthcare applications, their approach primarily aimed to accommodate the existing confusion in the field, rather than resolve it by addressing the ambiguity surrounding terms like non-immersive, semi-immersive, and immersive VR. We believe there is significant confusion regarding what constitutes different levels of immersion in VR environments, particularly in defining non-immersive and semi-immersive VR. Meanwhile, current definitions of immersive VR are often limited solely to the use of HMD head-sets, overlooking other modern technologies that stimulate additional exteroceptive senses (as presented in Chapter 2.2). Additionally, there also appears to be confusion about whether VR is understood as an immersive environment or as an environment that can encompass various levels of immersion. This lack of clarity underscores the need to develop a more refined framework specifically addressing the concept of immersion. To the best of our knowledge, our proposed framework is the first in the healthcare field to tackle this issue comprehensively. Our article serves as a starting point for establishing uniform terminology in this field, which appears to urgently require a standardized approach. We believe it will contribute to reducing ambiguity and facilitating clearer communication within the field.”
6. The proposed framework seems to suggest that non-immersive VR is not nearly as important or effective as immersive VR and should not be included in the definition of VR at all. Why does a distinction between immersive and non-immersive VR necessitate the need for such distinction in the definition? Non-immersive VR can still be effective for those with musculoskeletal disorders and chronic pain. This seems akin to exercise, in which aerobic and resistance exercise and distinct types of exercise with different effects on health outcomes. But both are still considered exercise. Why can’t immersive and non-immersive VR be classified similarly? What if it is unsafe for someone to wear an HMD and they would greatly benefit from non-immersive VR. Separating them so much might discourage healthcare providers from using non-immersive VR, despite the potential benefits.
RESPONSE: Thank you for your comment. Our article does not aim to compare VR environments based on their effectiveness. Instead, it focuses on addressing terminological challenges in the field. We agree that it would be misleading to suggest that our proposed terminology is based on the effectiveness of specific technological solutions. To avoid any such misunderstanding, we have removed the following sentence from Proposition 2:
“Evidence from healthcare further supports the validity of this distinction, with studies demonstrating that immersive and non-immersive experiences have varying effects [77,78].”
Additionally, we reviewed the entire manuscript to ensure that no statements imply a comparison of the effects of different VR environments. This is to avoid conveying the incorrect message that the separation of non-immersive VR environments from VR is based on differences in their effectiveness.
Our distinction between non-immersive and immersive VR environments is solely based on the equipment used and the technological solutions they provide. As explained in our response to Comment 4, immersiveness is a technical attribute of the system. We agree with authors who define VR as inherently immersive (see lines 116-118), and for this reason, we have separated non-immersive environments from VR. To our knowledge, this is the first attempt to clearly define what constitutes non-immersive environments versus immersive VR.
This separation is not intended to discourage the use of non-immersive environments in healthcare but rather to establish a clear and standardized framework for understanding and categorizing VR technologies based on their technical characteristics. We believe this distinction will facilitate more precise communication within the field and support the effective implementation of both immersive and non-immersive technologies in clinical practice.
To clarify this in the article, we have added the following text to Proposition 2 (lines 367-377):
“We would like to emphasize that this distinction is not based on differences in the effectiveness of non-immersive and immersive environments. The separation of non-immersive environments is made based on the technological solutions these envi-ronments offer compared to immersive ones. As presented in the review article by Wilkinson et al., (2021) immersion is described as "a more objective quality of VR" and "the technical qualities of a system". Furthermore, this distinction aligns with certain proposals from other authors in the field who also define VR as exclusively immersive environments [44,46,47]. This separation is not intended to discourage the use of non-immersive environments in healthcare but rather to establish a clear and standardized framework for under-standing and categorizing VR technologies based on their technical characteristics.”
7. Proposition 3 of the proposed framework does not appear to be based on any evidence from the field of VR at all. With this lack of data, is it perhaps too soon to propose this framework?
RESPONSE: Thank you for your comment. To address the reviewer’s concern, we have added a reference to Proposition 3 that describes the use of interoception stimulation in conjunction with VR in the medical field (see lines 405-410):
“To the best of our knowledge, no research in the healthcare field has yet combined VR with interoception stimulation. However, there are articles that discuss the integration of internal body stimulation with VR in the medical field [83], highlighting the need to reconceptualize certain previous frameworks that suggested interoception stimulation with modern technology was not possible [39].”
Since our article primarily focuses on the terminology and understanding of concepts related to VR, we believe it is appropriate to also highlight emerging areas, such as interoception stimulation, even though research in this domain is still limited. With the proposed framework, we aim to encompass all possibilities that VR currently offers, regardless of the number of studies available in this field. We also want to emphasize the possibility of interoception stimulation, as previous proposed frameworks stated that internal body stimulation was not possible.
8. The proposed framework seems to focus primarily on immersive VR. Section 3 focuses entirely on immersive VR. Together, these suggest that the authors feel the evidence for the benefits of immersive VR far outweigh those of non-immersive VR. However, they have no used evidence in the field to make that compelling argument. Evidence clearly supports the benefits of immersive VR on pain over non-immersive VR because of greater presence and distraction, but this case has primarily been made for acute pain relief, not chronic pain relief. In addition, no such case has been made for musculoskeletal rehabilitation.
RESPONSE: Thank you for your comment. We appreciate the opportunity to clarify our intentions. Our proposed framework and article do not aim to prioritize immersive VR over non-immersive VR or suggest that immersive VR is inherently more beneficial. Instead, our primary focus is on addressing terminological challenges and providing a standardized framework for understanding and categorizing VR technologies based on their technical characteristics.
To ensure this point is clear, we reviewed Section 3 and the rest of the manuscript to verify that no content implies a direct comparison between the benefits of immersive and non-immersive VR. Our framework is not intended to advocate for one type of VR over another. Instead, it seeks to provide clarity on what constitutes immersive and non-immersive environments, which is essential for interpreting evidence and facilitating communication in the field.
To address this concern explicitly in the article, we have added the following clarification to Section 2.3 (see lines 334-338):
“Our framework is not intended to prioritize immersive VR over non-immersive VR or to suggest that one is inherently more beneficial than the other. Instead, it seeks to address existing terminological inconsistencies and provide a standardized basis for understanding VR environments based on their technical characteristics.”
We hope this addition and clarification address your concerns and demonstrate the scope and intent of our framework.
Minor Revisions:
1. Please differentiate musculoskeletal rehabilitation from neurological rehabilitation. Lines 34-38 suggest that VR has been more easily applicable in neurological rehabilitation rather than musculoskeletal rehabilitation because it’s use in improving motor function. However, musculoskeletal rehabilitation can also focus on motor function, depending on what a person is struggling with.
RESPONSE: We appreciate this observation and have revised the text to clarify the differences between musculoskeletal and neurological rehabilitation. In the updated manuscript, we now explicitly acknowledge that motor function improvement is a key focus in both fields. However, we also highlight the differing primary objectives: while neurological rehabilitation often centers on facilitating cortical reorganization and restoring motor control after neural injury, musculoskeletal rehabilitation typically emphasizes goals such as improving range of motion, increasing muscle strength, and managing pain. These distinctions have been integrated into the revised introduction to provide a clearer differentiation.
Updated text (lines 38-40):
“Although motor function improvement is also an important focus in musculoskeletal rehabilitation, the field often emphasizes goals such as enhancing range of motion, increasing muscle strength, and managing pain.”
2. Please provide evidence for the statement that cost is a major barrier to healthcare adoptions of VR-based treatments (lines 38-41).
RESPONSE: Thank you for pointing this out. To address this comment, we have provided evidence supporting the claim that financial costs are a significant barrier to the implementation of VR in healthcare. We have cited a recent scoping review that specifically identifies financial costs as a notable challenge in adopting VR-based treatments. Additionally, we included evidence indicating that VR may, in fact, be cost-saving for managing chronic musculoskeletal conditions, providing a balanced perspective.
Updated text (lines 40-46):
“At first glance, it may seem that these objectives would not significantly benefit from VR compared to traditional non-VR interventions, raising questions about its cost-effectiveness for widespread adoption in the musculoskeletal field. Accordingly, a recent scoping review identified financial costs as one of the barriers to the implementation of VR in healthcare [5]. However, it appears that in the field of chronic musculoskeletal conditions, VR may be cost-saving compared to non-VR interventions [6].”
3. Second 2.1 would benefit from differentiating between industry and research. How much is XR actually used in research, despite its common use in industry?
RESPONSE: In response to your comment, we have revised Section 2.1 to better differentiate between the use of XR in industry and research. Specifically, we have added a discussion highlighting that, while XR technologies are frequently used in industry for training, simulations, and entertainment—often emphasizing more immersive technologies—applications in healthcare tend to rely more on non-immersive approaches.
Below, we have included the text added to Section 2.1 (lines 215-223):
“One possible explanation for this discrepancy is the frequent use of various types of XR technologies in industry, particularly for training, simulations, and entertainment, where more immersive technologies often take center stage. In contrast, applications in healthcare tend to rely more on non-immersive approaches, such as Nintendo Wii games, a technology whose production in the industry ended in 2013. When it comes to immersive experiences, healthcare primarily utilizes immersive VR, while the use of MR and AR currently lags behind. This is likely due to the increasing accessibility of immersive VR, whereas MR and AR remain relatively recent developments.”
4. The second paragraph of section 2.2 seems to discuss definitions of VR based on levels of immersion. But the examples the authors include all differ based on interaction, not immersion.
RESPONSE: Thank you for your observation. In Section 2.2, our goal was to present definitions commonly found in healthcare literature for terms such as "non-immersive VR," "semi-immersive VR," and "immersive VR." While these definitions primarily focus on levels of immersion, they also reveal differences in how interaction is conceptualized. For example, some definitions describe "non-immersive" environments as interactive, while others do not.
Our intention was not to define the differences between interactive and non-interactive VR environments. Instead, our goal was to present the current understanding of what constitutes "non-immersive VR," "immersive VR," and "semi-immersive VR." This understanding evidently varies, including differences in the types of interaction described within these environments.
We hope this clarification addresses your concern.
5. Please provide some evidence for the statement in lines 285-287. This point is pivotal to the entire argument of this paper around needing uniform terminology. However, it appears most research to date does a fairly good job describing the specific VR used, which would reduce the risk of this happening.
RESPONSE: In response to Comment 2 (in major revisions), we removed the statement referenced in lines 285–287 and rephrased the text accordingly (please see our response to Comment 2 for details). In that response, we also provided additional clarification on why the need for uniform terminology persists.
While we agree that providing a precise description of the equipment and use of VR is essential, we believe that the lack of consistency in understanding terms such as non-immersive, immersive, and semi-immersive VR underscores the continued importance of establishing uniform terminology. This would help ensure clearer communication and reduce potential misunderstandings across the field.
6. Figure 2: Is there evidence that people do not feel immersed or present when using wii games at all. A quick search found some research to suggest that presence is certainly lower than more immersive environments, but presence is not totally gone (Born et al., IEEE Xplore, 2019; Pallavicini et al., 2019)
RESPONSE: Since immersion primarily refers to the objective technological aspects of an environment, as discussed in our response to Reviewer Comment 4 (in major revisions), we believe that the term "non-immersive VR" is an appropriate name for environments where the technology does not allow for full visual immersion. Non-immersive environments are thus defined based on the technological capabilities rather than the subjective sense of presence.
We do not claim that the sense of being there or perceived realism is impossible in non-immersive environments. Rather, we distinguish non-immersive from immersive environments based on the technology used. Therefore, we believe the term "non-immersive" for environments that do not enable complete visual immersion is appropriate and not contradictory to evidence suggesting that a sense of presence is achievable even in non-immersive environments.
To better clarify this, we have added the following text to the article in Proposition 2 (line 355 and 363-366):
“For VR in healthcare currently labeled as "non-immersive," which typically involves the projection of artificial environments on a computer or television screen (e.g., Wii games) and does not allow for complete visual detachment from the real world, regardless of whether these environments are interactive or non-interactive, we propose the term "non-immersive fully artificial environments".”
“Non-immersive fully artificial environments can still provide a certain degree of presence[79]. However, since the technology used in these environments does not allow for complete visual detachment from the real world, we categorize them as non-immersive environments.”
7. Lines 469-470 state that the same software rarely appears in more than one study. Could this be due to the fact that most of this research is conducted by the tech companies themselves? This is an important point that should be included and considered in the discussion of bridging the gaps between research and clinical care.
RESPONSE: To address the reviewer’s comment, we have added the following sentence to the text (lines 533-535):
“This variability could be attributed, at least in part, to the possibility that some of this research is funded by technology companies developing proprietary VR systems [128].”
We also reviewed studies in the field of musculoskeletal rehabilitation that investigate the use of immersive VR and found only one study (Garcia et al., 2021) that was funded by a technology company (Applied VR). Therefore, we did not include a more extensive discussion on this topic in the article.
REVIEWER 2
The work is well done, the analysis collects in my opinion the main aspects to take into consideration in this field and the narration is well conducted. The references are appropriate both in number and selection, the graphic part is clear and well understandable by the reader, the results stimulating for the reader.
RESPONSE: Thank you for your kind and encouraging feedback. We are delighted that you found our work well-conducted, with a comprehensive analysis and appropriate references. We are also pleased that the graphical elements were clear and that the results were stimulating for the reader.
REVIEWER 3
In the academic editor notes, you stated that the revisions should address the overall comments from Reviewer 1 and the specific comments from Reviewer 3 regarding the discussion and conclusion. Therefore, only the comments related to the discussion and conclusion are provided below.
Discussion
There is no critical analysis of the studies included in the review.
The discussion does not explore how the findings could be directly applied in rehabilitation settings.
Often, the discussion seems disconnected from the challenges mentioned in the introduction and the results presented.
RESPONSE: Thank you for your comment. Since the reviewer has indicated that these comments pertain to the discussion, and our article does not include a section specifically titled "Discussion," we are unsure about the exact revisions being requested. However, we believe that we have addressed the concerns raised through revisions made in response to comments from Reviewer 1.
For instance, we expanded the justification for our proposed framework in Section 2.3 (please see our response to Comment 5 from Reviewer 1 in major revisions). Additionally, in the final paragraph of the introduction, we explicitly describe how our findings can contribute to clinical practice.
If there are further specific areas the reviewer would like us to address, we would be happy to provide additional clarification.
Conclusion
The conclusion provides a general summary of challenges and opportunities but does not include specific recommendations for professionals or researchers.
No concrete steps are proposed to address identified gaps, such as the need to standardise terminology or develop specialised software.
RESPONSE: Thank you for your comment. To address your concerns, we have revised the conclusion to include specific recommendations, particularly regarding the development of software solutions (lines 700-701):
“Current software solutions often fail to leverage VR's full potential mechanisms, such as its impact on kinesiophobia and body image through the use of body illusions or body-swapping techniques, highlighting the need for the development of additional software solutions in the field of musculoskeletal rehabilitation.”
Additionally, we have addressed the need for standardized terminology in Section 2.3, where we provide a detailed justification for this requirement. This is also outlined in our response to Comment 5 from Reviewer 1 (in major revisions).
We hope these additions clarify our intentions and provide concrete steps to address the identified gaps.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsAbstract
- The abstract does not provide a clear formulation of the problem or the specific objectives of the study.
- It fails to highlight the key results or contributions of the article, leaving uncertainty regarding the impact of the proposed ideas.
- The practical application of the information in the context of rehabilitation is not mentioned, which could attract greater interest from professionals in the field.
Introduction
- The introduction provides general information about VR but does not conceptually address the “Management of Musculoskeletal Conditions and Chronic Pain” or the specific challenges faced in musculoskeletal rehabilitation and chronic pain management.
- The connection between the mentioned challenges (e.g., inconsistent terminology, variety of hardware/software) and the study's objectives is insufficiently developed.
- Although the evolution of VR usage in various contexts is mentioned, there is limited reference to recent studies justifying the relevance of the proposed analysis.
Methodology
- This section is not clearly defined as a chapter.
- While it is an umbrella review, there is no clear explanation of the criteria used to select the studies analysed.
- The methods used to categorise the technologies or VR subtypes mentioned are not detailed.
- There is no comprehensive description of the databases used, the keywords applied, or the analysis period, compromising reproducibility.
Results
- The results are not clearly presented as a distinct chapter.
- The challenges mentioned are not supported by concrete data to validate the claims.
- The categorisation of technologies, immersion, and other concepts is scattered, making comprehension difficult.
- Although technologies such as HMDs are mentioned, there is no in-depth discussion of their impacts on clinical outcomes.
- It is suggested to include a table to present the results more clearly.
Discussion
- There is no critical analysis of the studies included in the review.
- The discussion does not explore how the findings could be directly applied in rehabilitation settings.
- Often, the discussion seems disconnected from the challenges mentioned in the introduction and the results presented.
Conclusion
- The conclusion provides a general summary of challenges and opportunities but does not include specific recommendations for professionals or researchers.
- No concrete steps are proposed to address identified gaps, such as the need to standardise terminology or develop specialised software.
Author Response
Dear Reviewer,
We sincerely thank you for your valuable comments and suggestions to improve our manuscript. We have carefully addressed all your comments and have provided detailed responses in the attached PDF document. We believe that the revised manuscript now meets the expectations of the journal and the review process.
Best regards, The authors
REVIEWER 1
This manuscript describes an overview of the current state of virtual reality (VR) in the healthcare field, specifically for persons with musculoskeletal conditions and chronic pain conditions. The authors first discuss the field wide issue of vague terminology and the ways in which that hinders VR from having been completely adopted in the healthcare sphere. The authors then propose a new framework to overcome such barriers. Finally, the authors summarize the current availability of hardware and software that could be utilized for different purposes in the healthcare sphere.
The authors take on a very important topic. It is clear that terminology is vague and that may limit our ability to use VR to its fullest potential in healthcare. However, I’m afraid that this publication ultimately adds more vagueness and complexity to the field rather than simplifying things. I think the goal of this manuscript is to make it easier for healthcare workers and providers to adopt effective VR tools for treatment. However, I don’t believe the manuscript as written accomplishes this goal. In short, it is unclear how the proposed framework shown in Figure 3b clarifies the use of VR in healthcare and helps providers use VR as a tool to help their patients.
RESPONSE: Thank you for your thoughtful feedback. We appreciate your recognition of the importance of addressing the challenges associated with vague VR terminology in the healthcare field and your acknowledgment of the manuscript’s focus on this critical topic. We understand your concerns and welcome the opportunity to clarify the purpose and goals of our work.
The primary aim of this manuscript is to address the inconsistencies in VR terminology that currently hinder communication in the healthcare field. While we agree that our proposed framework may initially introduce new concepts, our intention is not to complicate the field but to provide a foundation for standardizing VR terminology based on levels of immersion and technological characteristics. By distinguishing between non-immersive, semi-immersive, and immersive VR environments, we aim to reduce existing ambiguity and improve communication among researchers, healthcare providers, and developers.
To further clarify the practical application of the proposed framework, we have expanded Section 2.3 to include a detailed justification for its necessity, as outlined in our response to Comment 5.
Regarding Figure 3b, we acknowledge your concern and have added a detailed explanation in the manuscript to ensure its relevance and applicability to healthcare providers is clear.
We hope these revisions address your concerns and demonstrate how our proposed framework and recommendations aim to simplify, rather than complicate, the use of VR in healthcare. If there are further specific areas you believe require additional clarification, we would be happy to address them.
Major Revisions:
1. There is no justification in the manuscript for the authors’ decision to focus on both musculoskeletal conditions and chronic pain. There are different ways in which VR would be applied to treatment for these conditions and there is major overlap in persons with musculoskeletal disorders and chronic pain. Is there enough evidence for the benefit of VR in the treatment of these conditions that it should be adopted in the healthcare space? References 5-10 (line 43) primarily points to VR for chronic pain rather than musculoskeletal disorders.
RESPONSE: Thank you for your insightful feedback. We have revised the manuscript to address your concerns.
Throughout the manuscript, we have replaced the term “musculoskeletal conditions and chronic pain” with “musculoskeletal conditions and associated chronic pain” to clarify that the scope of the article is limited to musculoskeletal conditions, which may include chronic pain as a common feature. This distinction ensures that the focus is not extended to chronic pain originating from non-musculoskeletal (e.g., neurological) conditions.
To justify our decision to focus on musculoskeletal conditions regardless of chronicity, we have added a paragraph highlighting the psychosocial factors prevalent across both acute and chronic musculoskeletal conditions, which can be effectively and similarly addressed through VR. Additionally, we have included examples of how VR can be applied to the treatment of these conditions.
Below is the text that we added in Introduction (lines 46-63):
“In addition, for patients with these conditions, the use of VR goes beyond mere distraction from immediate pain. Recovery success in patients with musculoskeletal pain, regardless of chronicity, can be hindered by various psychosocial factors [7–13], which can be addressed through VR. VR can benefit patients with kinesiophobia by providing distraction from fear, which facilitates movement [14], or through gradual exposure to feared movements, enabling desensitization and reducing fear responses over time [15]. A fun, engaging, and interactive form of therapy is offered through VR, enhancing patient motivation for rehabilitation [16–18]. By enabling patients to develop skills for self-regulation of pain through interactive and sensory-augmented experiences, such as controlling unpleasant virtual elements via biosensor feedback or practicing deep breathing techniques in gamified environments, it also serves as a tool to improve self-efficacy [19]. Additionally, it facilitates embodiment, allowing users to perceive the virtual body as their own [20,21]. Consequently, during and after VR interventions, users exhibit attitudes or behaviors aligned with the characteristics of the virtual avatar, a phenomenon known as the Proteus effect [22,23]. By leveraging embodiment in virtual avatars, VR can help address altered body image [24,25], which is often particularly pronounced in cases of chronic pain [26] and can contribute to dysfunctional pain-coping strategies, such as movement avoidance [27].”
To address the concern regarding the focus of references, we have incorporated additional studies that demonstrate the effectiveness of VR across musculoskeletal conditions, not exclusively associated with chronic pain. These include: Elaraby et al. (2023) and Garcia Sanchez et al. (2023), that focus on orthopaedic ankle injuries and postoperative rehabilitation following total knee arthroplasty. We reformulated the text accordingly to reviewer’s comment (lines 63-66 in Introduction):
“Furthermore, meta-analyses have increasingly highlighted the significant benefits of VR in managing musculoskeletal conditions and associated chronic pain [26–34], underscoring its potential as a valuable tool for integration into healthcare to effectively address these conditions.”
2. The authors talk a lot about the need for defining specific terms in VR to better facilitate translation of research into clinical care. In addition, the authors discuss how this vagueness in terminology has led to researchers being very specific in describing the characteristics of the VR they use (e.g., immersion, interaction). Can the authors clarify why unifying terminology is so important when it does not provide as much clarity as these specific characteristics of the VR?
RESPONSE: Thank you for your feedback. In response, we have clarified the importance of unifying terminology in the manuscript. To address this, we have added the following explanation to the text (Section 2.2; lines 304-314):
“Overall, the inconsistency in VR terminology highlights the need for researchers and practitioners to precisely define the equipment and methods they use [38]. While detailed descriptions of interventions are valuable, the need for such precision can increase the risk of errors—if an intervention is not thoroughly described, reliance may fall solely on (potentially inaccurate) terminology. Different interpretations of the same terms can lead to the inclusion of various types of interventions under a single label. For example, in the case of non-immersive VR, it is currently unclear whether such environments require interaction from the user or not. Uniformity in terminology would facilitate clearer communication within the field by reducing the need for highly detailed descriptions of the technology used and its intended purpose, ensuring a shared understanding of key concepts.”
3. The paragraphs on modern definitions of VR (lines 93-128) lacks focus and direction. There is no sense of understanding the history of VR and how it’s changed over time. In addition, the very basic definition of VR attributed to Ditchburn et al, 2020, actually stems from some original VR research done in the 1990’s (Ellis, 1991; Lombard et al., 1997).
RESPONSE: Thank you for your comment. We have revised the section to provide a clearer narrative and include historical context.
To address the lack of historical context, we included references to early definitions of VR in the rehabilitation field from the 1990s (lines 129-132):
“Such a broader understanding may also stem from some of the earliest definitions in rehabilitation from the 1990s, which did not limit VR to immersive systems but described it as including HMDs as well as other equipment such as monitors or large screens [54,55].”
We have shortened and revised the section you mentioned (last paragraph of Section 2) to improve clarity. In this paragraph, our aim was to highlight the differences in VR definitions, focusing specifically on the field of healthcare, with a more focus on musculoskeletal rehabilitation. The intention of this section was not to provide a historical overview of VR terminology but rather to emphasize the aspects in which definitions differ and explore the possible reasons for these differences.
a. Lines 124-125 state that the variety of VR applications signifies a lack of understanding of what VR is. Could an alternative explanation be that VR is a very broad term and these studies underly the myriad of ways that VR is being used to improve chronic pain and musculoskeletal rehabilitation? In that case, aren’t more specific descriptions of characteristics of what is being used advantageous for clinical providers looking to adopt a similar treatment tool?
RESPONSE: In response to the comment, we have added an alternative explanation that VR can be considered a very broad term in the field of healthcare (Lines 127-135):
“This discrepancy indicates that VR in healthcare encompasses a broad spectrum of technologies and that VR remains a very broad term in this field. Such a broader understanding may also stem from some of the earliest definitions in rehabilitation from the 1990s, which did not limit VR to immersive systems but described it as including HMDs as well as other equipment such as monitors or large screens [56,57]. On the other hand, the inconsistency in reported definitions poses significant challenges. These inconsistencies limit the understanding and applicability of research findings, restrict researchers from identifying relevant studies, and raise unrealistic expectations about the potential of these novel solutions [40,58].”
We agree that precise descriptions of interventions are necessary. However, we believe that the lack of clarity in definitions also introduces certain risks, which we have highlighted in the text and addressed in our response to Comment 2 from Reviewer 1.
4. The authors spend significant time discussing characteristics of VR including immersion and interaction. There is no mention of presence, which is highly important in VR and is comprised of characteristics including immersion and interaction. In addition, the authors hypothesize that there should be a clearer definition of immersion, but immersion is inherently subjective, based on individuals’ feelings of being in the virtual environment. Aside from HMDs in which immersion in very clear as the real world is occluded, feelings of immersion cannot be completely objective.
RESPONSE: Thank you for your thoughtful comment. We would like to clarify why the term presence does not appear in the sections where we discuss the current state of VR definitions. Specifically, we did not encounter the term presence in the definitions of VR commonly found in healthcare literature. As a result, definitions incorporating presence are not presented in the early sections of the manuscript (e.g., Sections 2, 2.1, and 2.2).
However, we agree that presence is a crucial concept in VR terminology. In light of your comment, we have added a discussion on presence to Section 2.3, where we address its importance and its relationship with immersion (lines 417-424):
»A higher number of stimulated senses enhances immersion and, consequently, the sense of presence by increasing the feeling of "being there” [83]. This occurs because more attentional resources are allocated to the virtual world as the number of stimulated senses increases [83]. The level of immersion increases not only with the number of virtually stimulated senses but also with the quality of virtual stimulation. The better the quality of virtual stimuli (e.g., the visual appearance of objects, tracking quality, etc.), the greater the immersion. This, in turn, contributes to higher perceived realism and subsequently enhances the sense of presence [83].«
Regarding the second part of your comment, we respectfully disagree with the assertion that immersion is inherently subjective. Based on our review of recent literature, immersion is typically described as an objective quality of VR, primarily determined by the technological capabilities of the system. In contrast, sense of presence refers to the subjective experience of being in the virtual environment. To further support this distinction, we reference Wilkinson et al. (2021), who conducted a review on the concepts of presence and immersion. Their findings clearly differentiate between the two:
»On the other hand, immersion is associated with the more technical aspect related to the illusion. It is a more objective quality of VR insofar as the technology is capable of providing realistic feedback, general interaction, and its ability to allow the user to move and behave as they would normally (Table 2). The thematic content analysis revealed two themes: presence is experiential, immersion is the technical qualities of a system that aide the feeling of presence.«
We believe these clarifications and the addition of the discussion on presence in Section 2.3 address your concerns and enhance the manuscript.
5. More justification is needed for a new proposed framework. How many previous frameworks have been proposed to unify terminology in this field? Why have they failed in doing so? How does this framework overcome those shortcomings? How does a newly proposed framework clarify the field rather than cause more confusion.
RESPONSE: Thank you for your comment. The frameworks we identified are discussed in Section 2.1 and presented in Figure 1. In the healthcare field, we found only one article by Abbas et al. (2023) that specifically addresses VR terminology in this domain (presented in Section 2.1; lines 202-208). To our knowledge, publication by Abbas et al., (2023) is the only publication attempting to define VR terminology for healthcare applications comprehensively.
The definition of VR proposed by Abbas et al. (2023) was designed to accommodate the existing confusion in the field and to encompass the broad range of interpretations of what
constitutes VR. Abbas et al. (2023) did not address the confusion surrounding the understanding of computer-generated environments offering varying levels of immersion, but instead tailored their definition to reflect the current ambiguity in the field. In contrast, our approach focuses on clarifying what VR means, with an emphasis on understanding computer-generated environments with varying levels of immersion.
We believe there is significant confusion regarding what constitutes different levels of immersion in VR environments, particularly in defining non-immersive and semi-immersive VR. Meanwhile, current definitions of immersive VR are often limited solely to the use of HMD headsets, overlooking other modern technologies that stimulate additional exteroceptive senses (as presented in Chapter 2.2). Additionally, there also appears to be confusion about whether VR is understood as an immersive environment or as an environment that can encompass various levels of immersion. This lack of clarity underscores the need to develop a more refined framework specifically addressing the concept of immersion. To the best of our knowledge, our proposed framework is the first in the healthcare field to tackle this issue comprehensively.
We do not believe that our framework introduces further confusion. On the contrary, it aims to address the existing lack of clarity regarding the definitions of non-immersive, immersive, and semi-immersive VR, as discussed in Section 2.2. Our article serves as a starting point for establishing uniform terminology in this field, which appears to urgently require a standardized approach. We believe it will contribute to reducing ambiguity and facilitating clearer communication within the field.
To address the reviewer's concerns, we have added the following justification to our article:
Section 2.1. (lines 206-208):
“Accordingly, in their literature review, Abbas et al., (2023) examined how the term VR is defined in the medical literature and proposed the following definition of VR: “VR is a three-dimensional computer-generated simulated environment, which attempts to replicate real-world or imaginary environments and interactions, thereby supporting work, education, recreation, and health.”. Their definition was constructed to accommodate the current confusion in the field and to encompass the broad range of interpretations of what constitutes VR.”
Section 2.3 (lines 317-334):
“The terminology surrounding VR in healthcare is characterized by inconsistency and ambiguity, particularly regarding levels of immersion. While Abbas et al. (2023) provided a comprehensive attempt to define VR terminology for healthcare applications, their approach primarily aimed to accommodate the existing confusion in the field, rather than resolve it by addressing the ambiguity surrounding terms like non-immersive, semi-immersive, and immersive VR. We believe there is significant confusion regarding what constitutes different levels of immersion in VR environments, particularly in defining non-immersive and semi-immersive VR. Meanwhile, current definitions of immersive VR are often limited solely to the use of HMD head-sets, overlooking other modern technologies that stimulate additional exteroceptive senses (as presented in Chapter 2.2). Additionally, there also appears to be confusion about whether VR is understood as an immersive environment or as an environment that can encompass various levels of immersion. This lack of clarity underscores the need to develop a more refined framework specifically addressing the concept of immersion. To the best of our knowledge, our proposed framework is the first in the healthcare field to tackle this issue comprehensively. Our article serves as a starting point for establishing uniform terminology in this field, which appears to urgently require a standardized approach. We believe it will contribute to reducing ambiguity and facilitating clearer communication within the field.”
6. The proposed framework seems to suggest that non-immersive VR is not nearly as important or effective as immersive VR and should not be included in the definition of VR at all. Why does a distinction between immersive and non-immersive VR necessitate the need for such distinction in the definition? Non-immersive VR can still be effective for those with musculoskeletal disorders and chronic pain. This seems akin to exercise, in which aerobic and resistance exercise and distinct types of exercise with different effects on health outcomes. But both are still considered exercise. Why can’t immersive and non-immersive VR be classified similarly? What if it is unsafe for someone to wear an HMD and they would greatly benefit from non-immersive VR. Separating them so much might discourage healthcare providers from using non-immersive VR, despite the potential benefits.
RESPONSE: Thank you for your comment. Our article does not aim to compare VR environments based on their effectiveness. Instead, it focuses on addressing terminological challenges in the field. We agree that it would be misleading to suggest that our proposed terminology is based on the effectiveness of specific technological solutions. To avoid any such misunderstanding, we have removed the following sentence from Proposition 2:
“Evidence from healthcare further supports the validity of this distinction, with studies demonstrating that immersive and non-immersive experiences have varying effects [77,78].”
Additionally, we reviewed the entire manuscript to ensure that no statements imply a comparison of the effects of different VR environments. This is to avoid conveying the incorrect message that the separation of non-immersive VR environments from VR is based on differences in their effectiveness.
Our distinction between non-immersive and immersive VR environments is solely based on the equipment used and the technological solutions they provide. As explained in our response to Comment 4, immersiveness is a technical attribute of the system. We agree with authors who define VR as inherently immersive (see lines 116-118), and for this reason, we have separated non-immersive environments from VR. To our knowledge, this is the first attempt to clearly define what constitutes non-immersive environments versus immersive VR.
This separation is not intended to discourage the use of non-immersive environments in healthcare but rather to establish a clear and standardized framework for understanding and categorizing VR technologies based on their technical characteristics. We believe this distinction will facilitate more precise communication within the field and support the effective implementation of both immersive and non-immersive technologies in clinical practice.
To clarify this in the article, we have added the following text to Proposition 2 (lines 367-377):
“We would like to emphasize that this distinction is not based on differences in the effectiveness of non-immersive and immersive environments. The separation of non-immersive environments is made based on the technological solutions these envi-ronments offer compared to immersive ones. As presented in the review article by Wilkinson et al., (2021) immersion is described as "a more objective quality of VR" and "the technical qualities of a system". Furthermore, this distinction aligns with certain proposals from other authors in the field who also define VR as exclusively immersive environments [44,46,47]. This separation is not intended to discourage the use of non-immersive environments in healthcare but rather to establish a clear and standardized framework for under-standing and categorizing VR technologies based on their technical characteristics.”
7. Proposition 3 of the proposed framework does not appear to be based on any evidence from the field of VR at all. With this lack of data, is it perhaps too soon to propose this framework?
RESPONSE: Thank you for your comment. To address the reviewer’s concern, we have added a reference to Proposition 3 that describes the use of interoception stimulation in conjunction with VR in the medical field (see lines 405-410):
“To the best of our knowledge, no research in the healthcare field has yet combined VR with interoception stimulation. However, there are articles that discuss the integration of internal body stimulation with VR in the medical field [83], highlighting the need to reconceptualize certain previous frameworks that suggested interoception stimulation with modern technology was not possible [39].”
Since our article primarily focuses on the terminology and understanding of concepts related to VR, we believe it is appropriate to also highlight emerging areas, such as interoception stimulation, even though research in this domain is still limited. With the proposed framework, we aim to encompass all possibilities that VR currently offers, regardless of the number of studies available in this field. We also want to emphasize the possibility of interoception stimulation, as previous proposed frameworks stated that internal body stimulation was not possible.
8. The proposed framework seems to focus primarily on immersive VR. Section 3 focuses entirely on immersive VR. Together, these suggest that the authors feel the evidence for the benefits of immersive VR far outweigh those of non-immersive VR. However, they have no used evidence in the field to make that compelling argument. Evidence clearly supports the benefits of immersive VR on pain over non-immersive VR because of greater presence and distraction, but this case has primarily been made for acute pain relief, not chronic pain relief. In addition, no such case has been made for musculoskeletal rehabilitation.
RESPONSE: Thank you for your comment. We appreciate the opportunity to clarify our intentions. Our proposed framework and article do not aim to prioritize immersive VR over non-immersive VR or suggest that immersive VR is inherently more beneficial. Instead, our primary focus is on addressing terminological challenges and providing a standardized framework for understanding and categorizing VR technologies based on their technical characteristics.
To ensure this point is clear, we reviewed Section 3 and the rest of the manuscript to verify that no content implies a direct comparison between the benefits of immersive and non-immersive VR. Our framework is not intended to advocate for one type of VR over another. Instead, it seeks to provide clarity on what constitutes immersive and non-immersive environments, which is essential for interpreting evidence and facilitating communication in the field.
To address this concern explicitly in the article, we have added the following clarification to Section 2.3 (see lines 334-338):
“Our framework is not intended to prioritize immersive VR over non-immersive VR or to suggest that one is inherently more beneficial than the other. Instead, it seeks to address existing terminological inconsistencies and provide a standardized basis for understanding VR environments based on their technical characteristics.”
We hope this addition and clarification address your concerns and demonstrate the scope and intent of our framework.
Minor Revisions:
1. Please differentiate musculoskeletal rehabilitation from neurological rehabilitation. Lines 34-38 suggest that VR has been more easily applicable in neurological rehabilitation rather than musculoskeletal rehabilitation because it’s use in improving motor function. However, musculoskeletal rehabilitation can also focus on motor function, depending on what a person is struggling with.
RESPONSE: We appreciate this observation and have revised the text to clarify the differences between musculoskeletal and neurological rehabilitation. In the updated manuscript, we now explicitly acknowledge that motor function improvement is a key focus in both fields. However, we also highlight the differing primary objectives: while neurological rehabilitation often centers on facilitating cortical reorganization and restoring motor control after neural injury, musculoskeletal rehabilitation typically emphasizes goals such as improving range of motion, increasing muscle strength, and managing pain. These distinctions have been integrated into the revised introduction to provide a clearer differentiation.
Updated text (lines 38-40):
“Although motor function improvement is also an important focus in musculoskeletal rehabilitation, the field often emphasizes goals such as enhancing range of motion, increasing muscle strength, and managing pain.”
2. Please provide evidence for the statement that cost is a major barrier to healthcare adoptions of VR-based treatments (lines 38-41).
RESPONSE: Thank you for pointing this out. To address this comment, we have provided evidence supporting the claim that financial costs are a significant barrier to the implementation of VR in healthcare. We have cited a recent scoping review that specifically identifies financial costs as a notable challenge in adopting VR-based treatments. Additionally, we included evidence indicating that VR may, in fact, be cost-saving for managing chronic musculoskeletal conditions, providing a balanced perspective.
Updated text (lines 40-46):
“At first glance, it may seem that these objectives would not significantly benefit from VR compared to traditional non-VR interventions, raising questions about its cost-effectiveness for widespread adoption in the musculoskeletal field. Accordingly, a recent scoping review identified financial costs as one of the barriers to the implementation of VR in healthcare [5]. However, it appears that in the field of chronic musculoskeletal conditions, VR may be cost-saving compared to non-VR interventions [6].”
3. Second 2.1 would benefit from differentiating between industry and research. How much is XR actually used in research, despite its common use in industry?
RESPONSE: In response to your comment, we have revised Section 2.1 to better differentiate between the use of XR in industry and research. Specifically, we have added a discussion highlighting that, while XR technologies are frequently used in industry for training, simulations, and entertainment—often emphasizing more immersive technologies—applications in healthcare tend to rely more on non-immersive approaches.
Below, we have included the text added to Section 2.1 (lines 215-223):
“One possible explanation for this discrepancy is the frequent use of various types of XR technologies in industry, particularly for training, simulations, and entertainment, where more immersive technologies often take center stage. In contrast, applications in healthcare tend to rely more on non-immersive approaches, such as Nintendo Wii games, a technology whose production in the industry ended in 2013. When it comes to immersive experiences, healthcare primarily utilizes immersive VR, while the use of MR and AR currently lags behind. This is likely due to the increasing accessibility of immersive VR, whereas MR and AR remain relatively recent developments.”
4. The second paragraph of section 2.2 seems to discuss definitions of VR based on levels of immersion. But the examples the authors include all differ based on interaction, not immersion.
RESPONSE: Thank you for your observation. In Section 2.2, our goal was to present definitions commonly found in healthcare literature for terms such as "non-immersive VR," "semi-immersive VR," and "immersive VR." While these definitions primarily focus on levels of immersion, they also reveal differences in how interaction is conceptualized. For example, some definitions describe "non-immersive" environments as interactive, while others do not.
Our intention was not to define the differences between interactive and non-interactive VR environments. Instead, our goal was to present the current understanding of what constitutes "non-immersive VR," "immersive VR," and "semi-immersive VR." This understanding evidently varies, including differences in the types of interaction described within these environments.
We hope this clarification addresses your concern.
5. Please provide some evidence for the statement in lines 285-287. This point is pivotal to the entire argument of this paper around needing uniform terminology. However, it appears most research to date does a fairly good job describing the specific VR used, which would reduce the risk of this happening.
RESPONSE: In response to Comment 2 (in major revisions), we removed the statement referenced in lines 285–287 and rephrased the text accordingly (please see our response to Comment 2 for details). In that response, we also provided additional clarification on why the need for uniform terminology persists.
While we agree that providing a precise description of the equipment and use of VR is essential, we believe that the lack of consistency in understanding terms such as non-immersive, immersive, and semi-immersive VR underscores the continued importance of establishing uniform terminology. This would help ensure clearer communication and reduce potential misunderstandings across the field.
6. Figure 2: Is there evidence that people do not feel immersed or present when using wii games at all. A quick search found some research to suggest that presence is certainly lower than more immersive environments, but presence is not totally gone (Born et al., IEEE Xplore, 2019; Pallavicini et al., 2019)
RESPONSE: Since immersion primarily refers to the objective technological aspects of an environment, as discussed in our response to Reviewer Comment 4 (in major revisions), we believe that the term "non-immersive VR" is an appropriate name for environments where the technology does not allow for full visual immersion. Non-immersive environments are thus defined based on the technological capabilities rather than the subjective sense of presence.
We do not claim that the sense of being there or perceived realism is impossible in non-immersive environments. Rather, we distinguish non-immersive from immersive environments based on the technology used. Therefore, we believe the term "non-immersive" for environments that do not enable complete visual immersion is appropriate and not contradictory to evidence suggesting that a sense of presence is achievable even in non-immersive environments.
To better clarify this, we have added the following text to the article in Proposition 2 (line 355 and 363-366):
“For VR in healthcare currently labeled as "non-immersive," which typically involves the projection of artificial environments on a computer or television screen (e.g., Wii games) and does not allow for complete visual detachment from the real world, regardless of whether these environments are interactive or non-interactive, we propose the term "non-immersive fully artificial environments".”
“Non-immersive fully artificial environments can still provide a certain degree of presence[79]. However, since the technology used in these environments does not allow for complete visual detachment from the real world, we categorize them as non-immersive environments.”
7. Lines 469-470 state that the same software rarely appears in more than one study. Could this be due to the fact that most of this research is conducted by the tech companies themselves? This is an important point that should be included and considered in the discussion of bridging the gaps between research and clinical care.
RESPONSE: To address the reviewer’s comment, we have added the following sentence to the text (lines 533-535):
“This variability could be attributed, at least in part, to the possibility that some of this research is funded by technology companies developing proprietary VR systems [128].”
We also reviewed studies in the field of musculoskeletal rehabilitation that investigate the use of immersive VR and found only one study (Garcia et al., 2021) that was funded by a technology company (Applied VR). Therefore, we did not include a more extensive discussion on this topic in the article.
REVIEWER 2
The work is well done, the analysis collects in my opinion the main aspects to take into consideration in this field and the narration is well conducted. The references are appropriate both in number and selection, the graphic part is clear and well understandable by the reader, the results stimulating for the reader.
RESPONSE: Thank you for your kind and encouraging feedback. We are delighted that you found our work well-conducted, with a comprehensive analysis and appropriate references. We are also pleased that the graphical elements were clear and that the results were stimulating for the reader.
REVIEWER 3
In the academic editor notes, you stated that the revisions should address the overall comments from Reviewer 1 and the specific comments from Reviewer 3 regarding the discussion and conclusion. Therefore, only the comments related to the discussion and conclusion are provided below.
Discussion
There is no critical analysis of the studies included in the review.
The discussion does not explore how the findings could be directly applied in rehabilitation settings.
Often, the discussion seems disconnected from the challenges mentioned in the introduction and the results presented.
RESPONSE: Thank you for your comment. Since the reviewer has indicated that these comments pertain to the discussion, and our article does not include a section specifically titled "Discussion," we are unsure about the exact revisions being requested. However, we believe that we have addressed the concerns raised through revisions made in response to comments from Reviewer 1.
For instance, we expanded the justification for our proposed framework in Section 2.3 (please see our response to Comment 5 from Reviewer 1 in major revisions). Additionally, in the final paragraph of the introduction, we explicitly describe how our findings can contribute to clinical practice.
If there are further specific areas the reviewer would like us to address, we would be happy to provide additional clarification.
Conclusion
The conclusion provides a general summary of challenges and opportunities but does not include specific recommendations for professionals or researchers.
No concrete steps are proposed to address identified gaps, such as the need to standardise terminology or develop specialised software.
RESPONSE: Thank you for your comment. To address your concerns, we have revised the conclusion to include specific recommendations, particularly regarding the development of software solutions (lines 700-701):
“Current software solutions often fail to leverage VR's full potential mechanisms, such as its impact on kinesiophobia and body image through the use of body illusions or body-swapping techniques, highlighting the need for the development of additional software solutions in the field of musculoskeletal rehabilitation.”
Additionally, we have addressed the need for standardized terminology in Section 2.3, where we provide a detailed justification for this requirement. This is also outlined in our response to Comment 5 from Reviewer 1 (in major revisions).
We hope these additions clarify our intentions and provide concrete steps to address the identified gaps.
Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
Comments and Suggestions for AuthorsMethodology
There is no clear detail on how the studies included in the review were selected, which compromises the transparency and reproducibility of the analysis.
Although this is an umbrella review, there is no explanation as to why this type of review was chosen instead of a systematic review or meta-analysis.
There is no clear explanation regarding the databases used and the specific search criteria, which may limit the scope and quality of the review.
Results
The organisation of the results could be clearer, with tables or figures that facilitate the understanding of the main findings.
The results could be analysed in greater depth, highlighting the most relevant trends and potential discrepancies between the reviewed studies.
Conclusion
More specific suggestions for future research that could further explore the study’s findings should be included.
There is no detailed discussion on how the results could be implemented in the field of musculoskeletal rehabilitation.
Author Response
We have addressed the reviewer’s comments point by point in the attached document. Please see the attachment.
Author Response File: Author Response.pdf
Round 3
Reviewer 3 Report
Comments and Suggestions for AuthorsAbstract
As a narrative review, the abstract could include concrete examples of the main findings.
It is unclear how the articles were selected for review (inclusion/exclusion criteria).
Introduction
Some parts of the introduction seem to belong to the literature review, making the text lengthy and dense.
The article mentions the need for a conceptual framework but does not clearly define specific objectives.
Methodology
There is no clear explanation of how the articles were selected, which compromises the study’s reproducibility.
Results
The presentation of results is very unclear.
More clearly defined subheadings for each section could improve readability and coherence.
Discussion
The article discusses the challenges of VR but could provide more direct comparisons with previous reviews on the topic.
Author Response
Please see the attachment.
Author Response File: 
Author Response.docx
Round 4
Reviewer 3 Report
Comments and Suggestions for AuthorsTransparency in the article selection process is a fundamental element in any literature review, as it allows for the evaluation of the quality and credibility of the research. However, in this article, there is no information regarding the methodology used for selecting the analyzed studies. It does not indicate how many articles were initially researched, how many were excluded, or what criteria were used for exclusion. The absence of these data compromises the study's reproducibility and makes it difficult to understand the scientific rigor adopted in the review. For greater clarity and reliability, it would be essential to present a flowchart or a detailed description of the selection process, including the databases used, search descriptors, and inclusion and exclusion criteria for the articles.
A apresentação dos resultados carece de maior rigor, pois não há referências explícitas indicando de quais artigos as informações foram extraídas. Essa ausência compromete a transparência e credibilidade da análise, dificultando a verificação das fontes e a compreensão da relação entre os dados apresentados e os estudos que os sustentam. Para tornar a exposição mais clara e estruturada, seria crucial incluir uma tabela de resumo, organizando os principais resultados e vinculando-os às suas respectivas referências. Isso proporcionaria uma visão mais sistemática e comparativa dos achados, facilitando a análise crítica e a interpretação dos dados.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
