⦵ 𝟕𝟖𝟒𝕸   𝕰⃤   𝖀⃤   𝕾⃤   𝕺⃤   𝕹⃤   𝖀⃤   𝕾⃤ 

VIRTUAL REALITY AS A TOOL FOR PAIN MANAGEMENT

ABSTRACT

With this study we set out to understand pain and how to operationalize its the perceptual dimensions to support its management by using immersive experiences that can prompt pain masking. By virtual reality (VR), which is arguably the most immersive technology currently, we seek to not only demonstrates the potential of VR for non-pharmacological pain relief, but also to lay the foundation for future advances in technology with our ultimate goal being to develop creative non-invasive brain-computer interfaces (BCIs) that use biometric data in real time for therapeutic and artistic expression. This development envisions a transformative approach to healthcare, where technology and creativity converge for holistic well-being. This device could be developed to address more serious problems, helping people with terminal illnesses and/or chronic pain. There is a robust body of evidence pointing to processes that should eventually lead, through experimental methodology, to the discovery of the behavioral factors that constitute the dimensions of pain and pain relief. Chronic pain, as a major public health challenge, affects both physical and psychological well-being. Traditional pain management strategies may be ineffective or have side effects, requiring innovative approaches. This research explores a VR-based solution for pain management that integrates behavioral insights to improve therapy effectiveness. We examined how real-time VR responses to biometric data and guided breathing exercises can influence pain responses.

What do you need to do to 'feel' or perceive less pain?

For this experiment, participants were recruited online and divided into experimental and control groups. The experimental group experienced a controlled Cold Pressure Test in a VR environment sensitive to biometric feedback, while the control group experienced a similar environment without VR. Physiological responses and subjective assessments of pain were measured using the EmotiBit device as an objective measure and the Visual Analogue Scale (VAS) for subjective reporting. Data was integrated in real time into the VR experience, affecting it to support immersion.

The VR group showed a reduction in pain perception and an increase in pain tolerance, with physiological data reflecting these changes. The study highlights how the immersive and adaptive qualities of VR, combined with guided breathing techniques, can negatively modify behavioral and emotional responses to pain. This is supported by the notion of pain masking, where a stimulus is presented to compete with the pain signal in order to distract the user's attention and influence their perception of pain. The reduction in pain perception in the VR group may be attributed to the immersive and responsive nature of the environment, improving pain masking with behavioral pain management strategies such as distraction and relaxation techniques.

The goal of the study is to understand pain management through a behavioral lens using VR, and to establish VR as an effective tool for pain relief. More research is needed to delve deeper into the underlying behavioral and cognitive mechanisms, to evaluate the long-term effects of VR, and to integrate these approaches into comprehensive pain relief and chronic pain treatment protocols.

KEYWORDS!

Virtual Reality (VR), Pain Management, Biometric Data, BCI.

INTRODUCTION

In recent decades, the use of virtual reality (VR) in research has advanced rapidly, driven by factors such as increased computer processing capacity, improved quality of VR equipment, and the decreasing cost of this technology, expanding its potential applications (Gregg & Tarrier, 2007; Tarr & Warren, 2002). In a recent article, it was foreseen that VR would expand into different areas, such as research (Loomis et al., 1999), training, rehabilitation, and more (Tarr & Warren, 2002).

Virtual reality has become an increasingly used tool in therapy, particularly for patients resistant to conventional evidence-based treatments, showing comparable effectiveness (Dellazizzo et al., 2020; Ferrer-García et al., 2017).

Long-standing research has demonstrated its high potential (Gregg & Tarrier, 2007) considering that virtual environments allow for controlled exposure to situations. Additionally, the inclusion of virtual reality can be effective in treating a variety of health problems.

From psychiatric disorders such as depression and anxiety, stress reduction and mood improvement (Anderson et al., 2017) to pain management and treatment of phobias (Freitas et al., 2021) and post-traumatic stress disorder (Eshuis et al., 2021) or eating disorders (Ferrer-García et al., 2017), virtual reality has proven to be a promising tool in the field of therapy and neuroscientific research, combining a high level of control (over the stimuli presented) and ecological validity. (Bohil et al., 2011)

In a recent study, 36 studies were collected in which virtual reality was used to treat patients with psychiatric disorders, finding that this therapy was effective in reducing symptoms overall (Park et al., 2019), particularly for anxiety, where virtual reality can be used as an exposure method. Additionally, it can also be used for the treatment of phobias and post-traumatic stress disorder. On the other hand, another interesting point is the possibilities in the treatment of schizophrenia (Dellazizzo et al., 2021), dementia, and autism (Wiebe et al., 2022). Baghaei et al. (2021) also found positive results in the use of virtual reality to treat depression and anxiety.

Virtual reality has also proven effective in pain management. In (Krainbuhl et al., 2022), it was found that, particularly in virtual reality therapy, a therapeutic narrative can be included to accompany the experience, which significantly reduced pain intensity levels and increased tolerance by 85%, while Groenveld (2023) found that virtual reality therapy was effective in treating chronic pain.

Virtual reality has also been used in clinical work, for example, in (Pourmand et al., 2018) analyzing 28 articles provides evidence to support the hypothesis that virtual reality therapy is effective as a distraction for reducing anxiety and pain in patients undergoing various medical procedures. In another study, VR has been used in the treatment of post-traumatic stress disorder. (Eshuis et al., 2021) found that virtual reality therapy was effective in reducing symptoms of post-traumatic stress in war veterans.

In conclusion, virtual reality presents itself as a promising tool in the field of therapy, with applications in a wide variety of health problems. Research continues to explore the potential of virtual reality in the treatment of mental and physical illnesses, and its use is expected to continue to increase in the future. Virtual reality can be a valuable tool to complement existing treatments and improve the quality of life of patients.

However, the limits of VR do not stagnate in the possibilities mentioned. The philosophical implications (Matsangidou, 2014) and experiential terms of modifying the experience one can have of time and space, where we are and how our senses perceive (Sanchez-Vives & Slater, 2005) are being explored. For example, questions related to how perception changes, being another parallelism (Aday, et al. 2020) the intersection with psychedelic experiences (Kaup, et al. 2023) as they are two alternatives that are booming. Both can have relaxing effects with the accompaniment of meditation or mindfulness techniques (Wang, et al. 2022).

A recent meta-analysis and systematic review show that the path to a consistent methodology is still in its infancy, as there is a proliferation of heterogeneous results, in turn showing that the quality of the evidence was low, with small samples, lack of statistical power (Burrai, et al., 2023). Years ago, the work of (Turner & Casey, 2014) had already encountered this problem, where they did not find a correlation between the outcome of the treatment and the rigor of the methodology, so it concluded that intervention studies with virtual reality must improve the rigor of their methodologies. In turn, the review by Horrigome et al. (2020) showed that VR is being used in anxiety disorders, however, the magnitude and duration of its effectiveness, and the impact of the treatment continue to be unclear. These points, which still present themselves as weak points (or areas for improvement), give us room to consider feasible to continue exploring the limits and possibilities of this technology.

Despite significant advances in the field of virtual reality, there are still gaps in knowledge that need to be explored. In particular, a deeper understanding of the underlying mechanisms that allow virtual reality to influence altered states of consciousness and associated cognitive processes is needed. Understanding these knowledge gaps will allow us to advance in the optimization and effective application of virtual reality in the therapeutic and wellness fields.

Furthermore, further research is needed to understand the long-term effects of virtual and augmented reality in pain management and other applications. While immediate benefits in terms of discomfort relief have already been identified, it is essential to deepen our understanding of how these benefits are maintained over the long term and how they can be improved. This research aims to provide a solid foundation for the effective application of virtual reality in the therapeutic and wellness fields.

In our case, we are interested in the possibility of VR and AR being used as effective and accessible therapeutic tools for the relief of emotional discomfort, pain management, and overall well-being improvement. We believe in the potential of virtual and augmented reality to offer immersive and personalized experiences that can promote greater self-awareness, facilitate relaxation and mind-body connection, and enhance the process of healing and personal transformation.

We seek to provide an innovative and promising alternative that complements and enriches conventional therapies. Our goal is to contribute to scientific and clinical advancement in this field, deepening solid knowledge about the therapeutic benefits of virtual reality and its practical application in healthcare and wellness settings.

METHODOLOGY

PARTICIPANTS

Participants are recruited regardless of their current pain status through online forms and are distributed using the double-blind technique in an equitable and random manner. The inclusion criteria for this research are based on an age range between 18 and 40 years, the ability to give informed consent, and the ability to follow experimental instructions. For other purposes, the exclusion criteria are related to previous real-world experience (more than 5 years) that influences results, medical conditions that affect pain perception, and contraindication for exposure to cold, due to the experimental design of our research.

Participants are assigned to each group: one experimental and one control. Subjects in the experimental group are expressed in aversive control, which consists of immersing the right hand in water. It includes virtual reality (VR) glasses with the Tripp VR (TRIPP Inc. 2021) software during the entire exposure. Participants in the control group are exposed to an aversive atmosphere (many of them in the water with snow), but cannot use virtual reality glasses. They may receive a control treatment, such as a distraction activation or a placebo.

INSTRUMENTS

Several instruments were used to measure and operationalize pain. Among them are the Emotibit equipment, which captures physiological variables such as heart rate, temperature, and electrodermal activity, as well as a numeric or visual rating scale for participants to rate their level of pain. These instruments allowed for the collection of both objective and subjective data on the participants' pain experience.

EMOTIBIT

The EmotiBit is a peripheral physiological device consisting of a set of multimodal sensors that allow for the collection of both physiological and emotional data. This includes electrodermal activity (EDA), compatible with various skin types due to a wide range of conductance. Additionally, it can record heart rate with high precision through photoplethysmography (PPG), using multiple wavelengths to capture blood volume from different body areas and a medical-grade temperature sensor. (Montgomery et al., 2023)

It enables simple and practical recording of biometric data as it is wireless and integrates with the open-source Arduino ecosystem, facilitating research processes. EmotiBit differs from other devices in that others require black box algorithms to access data. Moreover, the information is 100% user-owned and features fully compatible hardware, capable of detecting physiological signals from multiple body areas. (Montgomery et al., 2023)

VISUAL ANALOGUE SCALE

The Visual Analogue Scale (VAS) (Kliger, et al., 2015) uses a scoring system ranging from 0 to 100, where 0 is 'not painful' and 100 is 'extremely painful'.

The time the subject kept their hand in the bucket and how long they kept it out of the water during the experiment was recorded. The value was calculated in total seconds of the test.

PROCEDURE

The procedure began by testing the comfort of the VR helmet on the participant. Next, the EmotiBit was placed on the middle finger of their left hand, ensuring it was properly fixed and functioning.

Participants were then subjected to a controlled stimulus, involving immersing their hand in a bucket of ice water following the Cold Pressor Test, a widely recognized cardiovascular assessment for its efficacy in measuring pain thresholds and tolerance (Miron et al., 1989; Mitchell et al., 2004; Mourot et al., 2009). This experimental pain test is used for its ability to effectively replicate "natural" pain. It is characterized as a highly standardized and easily reproducible procedure, making it an excellent simulator of acute pain in clinical contexts. This allows for appropriate extrapolation of research findings (Muñoz and Pedemonte, 2007; Mourot et al., 2009). Participants were instructed that they could remove their hand at any time if they wished, but were encouraged to keep it in the bucket as long as possible.

After immersing their hand, the Visual Analogue Scale (VAS) was applied. The virtual reality experience was conducted using the free trial version of the Tripp application (TRIPP Inc. 2021), lasting about 8 minutes. During this time, participants were immersed in a meditation experience while keeping their hand in the ice water.

This procedure follows the guidelines outlined in Krainbhul, et al., (2022). The research protocol was approved by the Ethics Committee of the Institute of Psychological Research (IIPsi) of the Faculty of Psychology of the National University of Córdoba, Argentina; and was conducted under the ethical principles established by the International Association for the Study of Pain (IASP, 2005).

During exposure to the painful stimulus, biometric data were collected using the EmotiBit, and participants rated their pain level using the numerical and visual rating scale. Before and after the intervention, evaluations were conducted using the aforementioned objective and subjective measures. This allowed for comparison of changes in physiological responses and pain perception between the experimental and control groups.

RESULTS

The Visual Analogue Scale for Pain was used to assess subjective pain perception in two different groups (virtual reality pain treatment group vs control group).

In group 1, a significant decrease in pain scores was observed after the intervention in all participants, indicating a reduction in pain perception. Participant 1 showed the greatest decrease from 70 to 10, while participant 2 had a decrease from 80 to 60.

In group 2, the pain score decreased considerably in 3 out of 4 participants after the intervention, with the third participant showing the greatest decrease from 20 to 0. However, the second participant experienced an increase in pain perception from 50 to 60. In group 1, a notable decrease in pain scores was observed after the experience.

For Group 1 - With VR, the statistical analysis yielded the following results:

t-value: 5.74

p-value: 0.0105

This result indicates a statistically significant difference in pain scores before and after the intervention for Group 1. Since the p-value is less than 0.05, we can conclude that the decrease in pain perception in this group is significant.

The time each participant was able to keep their hand in ice water was measured before and after the intervention.

In group 1, the participants increased the time to be able to keep their hand in the ice water, with participant one having the greatest increase with a value from 376.76 s to 517.05 s. Regarding group 2, the participants also managed to increase the time spent in the frozen container, maintaining a contrasting time in the third participant before and after the intervention.

For Group 2 - Without RV, the results of the statistical analysis are as follows:

t value: 1.12

p value: 0.343

In this case, the p value is greater than 0.05, indicating that there is no statistically significant difference in the pain scores before and after the intervention for Group 2. This suggests that the intervention did not have a significant effect on pain perception in this group.

In summary:

Group 1 - With VR: There was a significant decrease in pain perception (p < 0.05).

Group 2 - Without VR: No significant differences were observed in pain perception (p > 0.05).

A comparison of pain levels between the two groups was performed based on the parameters collected by the Emotibit.

Group 1 showed considerable variability in pain levels with a general average that suggests a moderate perception of pain, while group 2 also presented variability in pain levels with a general average slightly lower than that of the first group.

The test results are paired for the times with the hand in the water as follows:

Group 1 (Figure 3):

t value: -2.75

p value: 0.0707

For Group 1, the price is 0.0707, the p is <0.05. This indicates that, although there is a tendency to have a prolonged time in the heat, the participants have to manage their hand in the water from the intervention, this time is not statistically significant.

Group 2 (Figure 4):

t value: -1.54

p value: 0.2221

In group 2, the p is 0.2221, but the value is 0.05. It is not significant that there is a difference between the two participants in the water before and after the intervention.

In summary:

Group 1: There is no significant difference in the time with the hand in the water (p > 0.05), but there is also a tendency to have an increase.

Group 2: No significant differences are observed in the time with the hand in the water (p > 0.05).

Fig 1. A decrease in pain scores is observed, with the most significant value in the first participant, followed by the third, fourth, and finally the second with the least significant score.

Fig 2. A significant decrease is observed in the perception of pain in the first participant of the Control group, followed by the fourth, while the third participant maintained the previous values and the second presented an increase in relation to the implementation of the distractor or placebo.

Fig 3. Below it is observed that the longest duration with the hand in the frozen container has been that of the second participant, followed by the first (due to a very slight difference), then the third and finally the fourth, in which the time has remained constant in relation to the first test.

Fig 4.    A continuación se puede visualizar que la mayor duración con la mano en el recipiente helado  ha sido la del cuarto participante, seguido del primero (Con una diferencia ínfima), luego el tercero  y finalmente el segundo presentando una diferencia a penas remarcable en relación al momento previo a la aplicación del distractor o placebo. 

Fig 5. Below you can see a greater decrease in the perception of pain in the GEl in relation to the CG, although it has also increased its pain tolerance in relation to the previous trials.

RESULTS ANALYSIS

The collected data were statistically analyzed to determine the existence of significant differences between the experimental and control groups.

Furthermore, the first independent variable consisted of immersing the right hand in ice water, and the second of the simultaneous presence or absence of VR during this exposure. The dependent variable consisted of the quantitative and qualitative difference in pain magnitude expressed by both groups, considering the absence of VR in one of them.

Electrodermal activity (EDA) reflects changes in sweat gland activity, which has been linked to states of emotional stress and physiological arousal, according to Boucsein (2012). In our experiment, an increase in electrodermal activity can be interpreted as a response to the pain caused by immersing the hand in ice water. It is anticipated that virtual reality (VR), when presenting calming or distracting content, may contribute to a decrease in electrodermal activity, which would translate into a diminished perception of pain.

Fluctuations in heart rate (HR) are recognized as indicators of emotional and physiological responses to pain, as noted by Rainville et al. (2006). An increase in heart rate could be interpreted as a reaction to stress and pain. Conversely, a stable or reduced heart rate might suggest more effective pain management, especially in subjects exposed to VR.

The Infrared PPG (PI) and Red PPG (PR) parameters represent changes in blood volume in the skin and offer a way to assess cardiovascular responses to pain. Allen (2007) highlights their usefulness in this context. Significant changes in these parameters are expected as an indication of a physiological response to pain, and it is anticipated that VR may moderate these responses.

Finally, skin conductance (SC), like electrodermal activity, serves as an indicator of sweat gland activity and has been used in the assessment of emotional responses and stress (Dawson et al., 2007). An increase in skin conductance could be interpreted as a response to pain. It is expected that VR intervention may attenuate this increase, thereby providing a calming or distracting effect.

DISCUSSION

The analysis of the data obtained reveals a notable difference in pain perception in the group using virtual reality (VR), compared to the control group. This finding supports the hypothesis that VR can be an effective tool in pain management, probably due to its ability to distract and provide an immersive experience that modulates the emotional and physiological response to pain. Although pain resistance increased in both groups, possibly due to habituation to the cold stimulus, the decrease was more pronounced in the VR group.

CONCLUSION

This study has demonstrated that virtual reality (VR) can be used as an effective tool for pain management, demonstrating changes and parameters of the technical equipment and an increase in pain tolerance measured by water immersion time. The use of parameters such as electrodermal activation, heart rate, and skin conductance allows for a detailed assessment and compensation of pain, allowing for variability in pain experience among participants. The perceived decrease in pain intensity and increased tolerance to it indicate a potential benefit of VR. However, individual variability in perception and possible habituation to the pain stimulus underline the need for further research for a deeper understanding of the underlying mechanisms and to assess the sustainability of VR effects over time, as well as possible integration with treatment protocols for pain relief and chronicity.

REFERENCES

Aday, J.S., Davoli, C.C., and Bloesch, E.K. (2020). Psychedelics and virtual reality: parallels and applications. Therapeutic Advances in Psychopharmacology, 10, 2045125320948356. https://doi.org/10.1177/2045125320948356

Allen, J. (2007). Photoplethysmography and its application in clinical physiological measurement. Physiological Measurement, 28(3), R1. https://doi.org/10.1088/0967-3334/28/3/R01

Anderson, A. P., Mayer, M. D., Fellows, A. M., Cowan, D. R., Hegel, M. T., and Buckey, J. C. (2017). Relaxation with immersive natural scenes presented through virtual reality. Aerospace Medicine and Human Performance, 88(6), 520-526. https://doi.org/10.3357/AMHP.4747.2017

Baghaei, N., Chitale, V., Hlasnik, A., Stemmet, L., Liang, H. N., and Porter, R. (2021). Virtual reality to support the treatment of depression and anxiety: scoping review. JMIR Mental Health, 8(9), e29681.doi: 10.2196/29681

Bohil, C.J., Alicea, B., and Biocca, FA (2011). Virtual reality in neuroscience research and therapy. Nature Reviews Neuroscience, 12(12), article 12. https://doi.org/10.1038/nrn3122

Boucsein, W. (2012). electrodermal activity. Springer Science and Business Media. https://doi.org/10.1007/978-1-4614-1126-0

Burrai, F., Sguanci, M., Petrucci, G., De Marinis, MG and Piredda, M. (2023). Effectiveness of immersive virtual reality on anxiety, fatigue and pain in cancer patients undergoing chemotherapy: a systematic review and meta-analysis. European Journal of Oncology Nursing, 64, 102340. https://doi.org/10.1016/J.EJON.2023.102340

Dawson, M.E., Schell, A.M., & Filion, D.L. (2007). The electrodermal system. In J. T. Cacioppo, L. G. Tassinary, & G. G. Berntson (Eds.), Handbook of psychophysiology (3rd ed., pp. 159-181). Cambridge University Press. https://doi.org/10.1017/CBO9780511546396.007,

Dellazizzo, L., Potvin, S., Luigi, M., and Dumais, A. (2020). Evidence on virtual reality-based therapies for psychiatric disorders: meta-review of meta-analyses. Journal of Internet Medical Research, 22(8), e20889. https://doi.org/10.2196/20889

Eshuis, L. V., Van Gelderen, M. J., Van Zuiden, M., Nijdam, M. J., Vermetten, E., Olff, M., and Bakker, A. (2021). Effectiveness of immersive treatments for post-traumatic stress disorder: A systematic review of virtual and augmented reality exposure therapy and a meta-analysis of virtual reality exposure therapy. Journal of Psychiatric Research, 143, 516-527. https://doi.org/10.1016/j.jpsychires.2020.11.030

Freitas, J. R. S., Velosa, V. H. S., Abreu, L. T. N., Jardim, R. L., Santos, J. A. V., Peres, B., and Campos, P. F. (2021). Treatment of exposure to virtual reality in phobias: a systematic review. Psychiatric Quarterly, 92(4), 1685-1710. https://doi.org/10.1007/s11126-021-09935-6

Gregg, L., & Tarrier, N. (2007). Virtual reality in mental health. Social psychiatry and psychiatric epidemiology, 42(5), 343-354.https://doi.org/10.1007/s00127-007-0173-4

Groenveld, T. D., Smits, M. L., Knoop, J., Kallewaard, J. W., Staal, J. B., de Vries, M., and Van Goor, H. (2023). Effect of a virtual reality application based on behavioral therapy on quality of life in patients with chronic low back pain. The Clinical Journal of Pain, 39(6), 278. doi: 10.1097/AJP.0000000000001110

Gutiérrez-Maldonado, J., Wiederhold, B. K., and Riva, G. (2016). Future directions: How virtual reality can further improve the assessment and treatment of eating disorders and obesity. Cyberpsychology, behavior and social networks, 19(2), 148-153. https://doi.org/10.1089/cyber.2015.0412

Horigome, T., Kurokawa, S., Sawada, K., Kudo, S., Shiga, K., Mimura, M., and Kishimoto, T. (2020). Virtual reality exposure therapy for social anxiety disorder: a systematic review and meta-analysis. Psychological Medicine, 50(15), 2487-2497. https://doi.org/10.1017/S0033291720003785

Kliger M, Stahl S, Haddad M, Suzan E, Adler R, Eisenberg E. Measuring chronic pain intensity: are the visual analog scale and the verbal rating scale interchangeable? Pain Practice 2015;15(6):538-47. DOI: 10.1111/papr.12216.

Krainbuhl, W. C., Moroni, V. M., Legeren, A. L., Alsina-Jurnet, I., and Bueno, A. M. (2022). Acute pain control in virtual environments: the effect of a therapeutic narrative. Latin American Neuropsychology Magazine, 14(2), 21-31. DOI: https://doi.org/10.5579/rnl.2022.0772

Matsangidou, M., Ang, C. S., Mauger, A. R., Intarasirisawat, J., Otkhmezuri, B., and Avraamides, M. N. (2019). Is your virtual self as sensational as the real one? Virtual reality: The effect of body awareness on the experience of exercise sensations. Psychology of sport and exercise, 41, 218-224.https://doi.org/10.1016/j.psychsport.2018.07.004

Miron, D., Duncan, G.H., & Bushnell, C.M. (1989). Effects of attention on the intensity and unpleasantness of thermal pain. Pain, 39(3), 345