Virtual reality for pain management

Virtual Reality (VR) is a fascinating technology that allows the user to be transported into a synthetic world they perceive as real and in which they can move and interact. The impressive potential of VR goes far beyond entertainment. As it evolves rapidly and becomes more accessible, it will stand out as a highly prized technology of the future in many fields, including medicine. It has its place as a simulation training tool and as a safe and effective therapeutic device to treat or complement the treatment of various types of health problems, including pain management. Here is where we stand in terms of applications and what we know about the effectiveness of VR for acute and chronic pain and pain anxiety.

A safe device with multiple therapeutic uses

In the directory that classifies medical devices according to their potential risk to health, virtual reality is part of Class I, which is low-risk and includes crutches, bandages and corrective glasses. VR has few or no side effects, which are reversible, and a session can be stopped at any time by the patient. This technology’s most well-known side effect is cyber kinetosis, a motion sickness-like condition that manifests itself as heartache, dizziness and sweating. That said, VR is not suitable for some patients, including those with epilepsy or specific eye problems (e.g., strabismus), pregnant women, as well as those with balance problems, migraines or motion sickness.

Among the uses for which virtual reality is indicated as a primary or complementary therapy to conventional methods are the management of pain (including neuropathic pain: related to the nervous system) and fear of pain, the management of anxiety (and boredom) pertaining to medical treatments and procedures, as well as the treatment of some psychological issues: phobias, addictions, post-traumatic stress disorder, eating disorders, OCD and schizophrenia. In addition, VR is also beneficial as a physiotherapy and rehabilitation tool – especially following a stroke, or to improve the motor skills or physical condition of the elderly or those living with specific disabilities – as well as to stimulate the cognitive abilities of older adults with mild cognitive impairment.

Virtual reality is very versatile and allows the creation of customized programs and scenarios in immersive universes that, depending on the needs, can be realistic or not. For example, to allow a senior who suffers from mild cognitive problems to practice maintaining their autonomy, it would be wise to have them live an immersive experience in a realistic virtual universe recreating the places of his daily life (apartment, grocery store, etc.); while to help a child who must have a blood test to be less anxious, it would be better to immerse him in a playful and soothing universe adapted to his age.

“Distraction” therapy for pain and fear of pain

Pain is not only a sensory experience but also a psychological, behavioural and cognitive one that involves our emotions, disposition and attention. In an article in the official publication of Family Physicians of Canada, authors Karen Arane, MSc, Amir Behboudi, MD CCFP(EM), and Ran D. Goldman explain how virtual reality affects pain, and not just the fear of it:

“The theory behind VR’s role in reducing not only anxiety but also pain is related to the limited attention span of human beings. Pain requires attention, and if some portion of that attention can be diverted (e.g., through interaction with the VR), the patient will have a slower response to emerging pain signals (Hoffman et al., 2011). Pain is detected by nociceptive receptors* located throughout the body that transmit pain signals to the central nervous system via A-δ and C fibres (Hoffman et al., 2011). Many analgesics work by interrupting the C-fiber pathway and thus influencing the way humans feel pain. Virtual reality does not interrupt pain signals but acts directly and indirectly on pain perception and reporting via attention, emotion, concentration, memory, and other senses (Gold et al., 2007).

A functional magnetic resonance imaging study of healthy patients using VR while exposed to a painful stimulus (thermal foot pain simulator) demonstrated a more than 50% reduction in pain-related brain activity in 5 brain areas (Hoffman et al., 2004). A study of 9 subjects aged 20-38 years compared VR simulation with opioid analgesics during thermal pain stimulation, and outcomes were measured from subjective pain reporting and functional magnetic resonance imaging (Hoffman et al., 2007). Virtual reality and opioid analgesics had very similar pain reduction results, and a combination of opioids and VR was shown to result in a significant additional reduction in pain signals (p < .01) (Hoffman et al., 2007).”

*Nociceptive receptors are the pain receptors.

There are two main types of pain: acute and chronic. Acute pain is caused by a dysfunction in the body and resolves when treated. Note that the term “acute” does not refer to the intensity of the pain. Chronic pain refers to pain that persists beyond three months. Virtual reality as a “distraction” therapy can be used to treat both types of pain. In addition to being used as a therapeutic distraction tool, VR is also being experimented with as a medium for therapeutic hypnosis. However, this use remains less common and less studied than its “distractive” counterpart, and the gain that virtual reality technology can bring to therapeutic hypnosis remains to be demonstrated.

Uses of VR for acute pain

Some of the examples of acute pain cases for which virtual reality is appropriate include patients who have just had a skin graft or are recovering from burns, those whose dressing changes are painful, children who receive treatments involving needles (puncture, injection, blood sampling, etc.) or women during labour prior to delivery. In the latter case, a systematic review and meta-analysis (Baradwan et al., 2022) recently concluded that virtual reality effectively reduces anxiety, increases satisfaction and improves pain management during normal labour. In terms of pain in children, it would be effective for both acute and chronic pain (Koller & Goldman, 2011). While pain such as that induced by an injection is brief, the accompanying anxiety can make the child reluctant to subsequent treatments. Common distractions are generally effective in reducing children’s pain and anxiety about medical procedures. Therefore, it is legitimate to think that the distractive potential of VR is increased tenfold by its high realism as well as the high engagement it elicits and that this gives it an advantage over other means of distraction, as the article from the official publication of the Family Physicians of Canada quoted earlier points out:

“Distraction is a common non-pharmacological technique used by health care professionals to manage and alleviate anxiety, and possibly pain, during painful procedures in pediatric patients (Koller & Goldman, 2012). Both passive distraction (e.g., watching television, listening to a book being read) and active distraction (e.g., interactive toys, electronic games) have been extensively studied and decrease pain and anxiety (Koller & Goldman, 2012). Virtual reality may offer greater distraction because it fully immerses the patient in another world and involves multiple senses (Malloy and Milling, 2010). Patients can actively or passively participate in many potential virtual reality programs (Faber et al., 2014; Hoffman et al., 2008; Hoffman et al., 2011 and Lagnado L. The Wall Street Journal. 2017. Jul. A virtual approach to real pain; p. A9).”

In an article in La Presse about pilot projects conducted at CHU Sainte-Justine using VR to relieve children during unpleasant or stressful procedures, researcher Sylvie LeMay and her colleagues observed that this technology brought benefits on several levels: “If we take the immersive virtual reality projects, we really saw a difference between the groups that had virtual reality and the groups that didn’t, on distress, memory, the procedure was easier to do, and there were very few side effects. One group had a little bit of nausea and dizziness, but overall very few side effects. It was very much appreciated by the parents, by the health care professionals who do the procedure, because often it makes the procedure easier, they don’t have to do it two or three times because the child is too agitated or scared.”

The fact that virtual reality makes it possible to avoid taking analgesics or to reduce their dosage is a considerable asset, especially for relieving chronic pain in adults as well as children, and acute pain in children, when some are less safe for them, as noted by Arane, Behboudi and Goldman: “Among the common pharmacological pain medications for children is opioid therapy, which is known to be highly addictive and tolerance inducing (Faber et al., 2014). Opioids also have an unfavourable safety profile in children, including side effects ranging from nausea and constipation to cognitive impairment and respiratory failure (Hoffman et al., 2008).”

VR is used for some mildly to moderately painful procedures as an alternative to sedation or anesthesia. This is the case at Children’s Hospital Colorado in the United States, which uses it for lumbar puncture in particular, which avoids the inconveniences associated with being asleep (fasting and recovery) while allowing the medical staff to invest the time that would have been spent preparing for anesthesia in another way. Virtual reality can also be used to lighten, or even normalize, the hospital stay of young patients by allowing them to have fun outside medical procedures with adapted playful experiences, which represents a plus for their psychological well-being.

Finally, we should mention that a recently published systematic review attests to the effectiveness of virtual reality therapies in relieving acute pain while recommending that certain avenues be explored. Their conclusion is as follows: “This systematic review found VR to be an effective tool for acute pain management. Findings from this review also underscore the importance of addressing the patient’s sense of presence and levels of immersion, interaction, and interest when deploying VR. Future VR studies should consider incorporation of anxiety, presence, and VR side effect measures in addition to acute pain metrics.”

The particular case of chronic pain

In Canada alone, nearly 8 million adults live with chronic pain. In 2019, the World Health Organization (WHO) recognized it as a disease in its own right. In addition, for the first time in forty years, the International Association for the Study of Pain (IASP), an association whose goal is to encourage and support the study of pain to improve its treatment worldwide, revised its definition of pain. While the old definition was “an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage,” the new definition is “an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage.”

A Practical Pain Management interview with three working group members charged with revising the definition provides insight into the depth of the change, which was made after two years of debates and consultation. “Although the changes in the definition might seem minor, considerable changes were made in the Notes that accompany the definition to reflect current scientific understanding of pain,” explains Dr. Srinivasa N. Raja, chair of the IASP working group. Regarding this new scientific understanding, he says, among other things, that “research in more recent years has indicated that some types of pain (namely, nociplastic pain) exemplified by conditions such as fibromyalgia and irritable bowel syndrome, may not be associated with tissue injury and may be associated with nervous system dysfunction.” Dr. Raja added that the change in the definition “included deletion of the sentence in the previous Notes that stated: ‘pain in the absence of tissue damage or any likely pathophysiological cause’ was usually due to psychological reasons.” The six notes that accompany the new definition are:

1. Pain is always a personal experience that is influenced to varying degrees by biological, psychological, and social factors.
2. Pain and nociception** are different phenomena. Pain cannot be inferred solely from activity in sensory neurons.
3. Through their life experiences, individuals learn the concept of pain.
4. A person’s report of an experience as pain should be respected.
5. Although pain usually serves an adaptive role, it may have adverse effects on function and social and psychological well-being.
6. Verbal description is only one of several behaviours to express pain; inability to communicate does not negate the possibility that a human or a nonhuman animal experiences pain.

**Nociception refers to the set of phenomena that occur in the central nervous system in response to a painful stimulus that activates the nociceptors, i.e., the pain receptors (Medical Dictionary).

The new classification of chronic pain mechanisms includes “nociceptive” pain, which is pain related to activation of the nociceptors (pain receptors); “neuropathic” pain, which is pain related to an injury or disease that affects the somatosensory system (part of the nervous system); and “nociplastic” pain, which is pain related to altered nociception despite the absence of evidence of tissue damage activating the nociceptors or of disease or injury affecting the somatosensory system.

Chronic pain is thus a complex phenomenon that can take many forms, affects many aspects of functioning and life, including multidimensional effects on various cognitive domains (Khera and Rangasamy, 2021), and is often difficult to manage. Therefore, the therapeutic approach that gains traction is an individualized, multidisciplinary one, as expressed by Dr. Raja: “We are optimistic that the revised definition may lead the clinician to not only listen to the patient’s complaints of pain, but to inquire about how the person’s pain interferes with their daily activities, quality of life, relationships, and social interactions. This information will help the provider implement a personalized, multidisciplinary, patient-centred pain management strategy.”

Medications prescribed to relieve chronic pain – most often nonsteroidal anti-inflammatory drugs and opioids – do not always provide the relief sought; this is not to mention that they can lead to undesirable short- and longer-term effects (tolerance, addiction, hyperalgesia, complications, etc.). In this context, non-pharmacological approaches are more than welcome to expand the available therapeutic arsenal. VR also allows for patient autonomy and control over their condition in the long term. “For the management of long-term pain, public opinion is currently in strong favour of self-management strategies as a first-line effective strategy to engage patients in actively managing their own health status (Elbers and al., 2018; Billot and al., 2021; Damush and al., 2016),” points out a recent systematic review and meta-analysis study specifically on the applications of VR for chronic pain management (Goudman et al., 2022).

In the case of chronic pain, virtual reality is most often used as a pain distraction therapy, as it is for acute pain, but there are exceptions, which we will expand on further. As summarized by the authors of the systematic review and meta-analysis cited above, it is believed that its efficacy as a pain distraction tool in both adults and children would be superior to conventional distraction methods, but moreover, due to brain plasticity, its long-term use could induce beneficial physiological changes in this direction. “VR is thought to be more effective than traditional methods of distraction (e.g., pleasant imagining, rhythmic cognitive activities, external focus of attention, and neutral imagining (Malcolm H. Johnson, 2005)) because of its immersive property, encompassing a patient’s visual and auditory processing and even physical actions, which, in theory, demand more attention (Mahrer and Gold, 2009). In addition to distraction as an underlying analgesic effect of VR, the long-term use of VR is expected to induce neuroplastic changes in the sensory and motor brain regions (Cheung and al., 2014).”

While the efficacy of virtual reality for the management of acute pain associated with medical procedures has been highlighted by several systematic reviews (Garrett et al., 2014; Shahrbanian et al., 2009; Malloy and Milling, 2010; Chan et al., 2018) and its use for this purpose is now common and accepted, the same cannot be said for its use for chronic pain, which is not as widespread and for which there are fewer studies. This makes the recently published systematic review and meta-analysis by Goudman and colleagues on the applications of VR for chronic pain management all the more interesting, concluding, ” This systematic review explored the outcome measurements that are influenced by VR in patients with chronic pain. A broad range of outcome variables was revealed, whereby an intervention using VR technology can induce pain relief and improvements in functioning. These findings indicate that VR not only has applications in acute pain management but also in chronic pain settings, whereby VR technology might be able to become a promising first-line intervention as a complementary therapy for patients with chronic pain.”

Deceiving neuropathic pain

We mentioned above that virtual reality can be used in ways other than as a distraction therapy for chronic pain management. This is the case in the context of so-called “neuropathic” pain, that is, pain related to an injury or disease that affects the somatosensory system (a part of the nervous system). In other words, it is a pain secondary to an attack on the nervous system (brain, spinal cord or nerves), and in 30% of cases, pharmacological treatment does not bring any relief.

In a report by La Presse on the experiments led by a team of Quebec researchers and therapists of VR to deceive this type of pain, professor and researcher Cyril Duclos explains the characteristics of this pain generated by the nervous system but whose mechanisms remain to be clarified: “What we understand about the origin of neuropathic pain is that there is no longer any information coming back from the limbs – from the lower limbs, for example, in the case of Mélanie, the project’s ‘patient-partner.’ This causes the representation of the body in the brain to change. And the more it has changed from before the accident, the more intense the neuropathic pain.” As the pain signal pathway between the affected limbs and the brain – the point of reception and interpretation of those signals – is short-circuited, the brain responds by producing pain signals itself.

And how can VR act in such a case? By immersing the patient in an immersive universe in which they move with feedback that suggests that the affected limbs are still in working condition so that the nerve information reaches the brain as if the limbs in question were indeed active. “The idea is to send information back to the brain so that the representation is replaced and thus reduce the pain. It’s like reprogramming the brain,” explains Cyril Duclos. The relief generated can last several hours in some cases; the patient in the report obtained relief for almost 24 hours. Because neuropathic pain can take many forms, this type of exploratory research aims to identify those that are most likely to respond to VR. In the research reported here, complementary approaches to virtual reality are also being tested: stimulation with electrodes placed on the affected limbs and “transcranial direct current stimulation.” The latter technique sends a small electrical current to certain regions of the motor and sensory cortex to increase their receptivity to the VR experience.

Although more studies on the topic are needed, a review of the literature on virtual reality in the treatment of neuropathic pain in people with spinal cord injury (Austin & Siddall, 2019) still came up with these encouraging findings: “Although the number of studies and individual sample sizes are small, these initial findings are promising. Given the limited options available for the effective treatment of neuropathic SCI pain and early evidence of efficacy, they provide valuable incentive for further research.” To clarify, of the 60 articles found, the authors of this literature review included nine articles involving 207 participants; all studies were exploratory and used head-mounted devices or 3D and 2D displays with virtual walking or limb movement imagery; outcomes included pain sensitivity, motor function, and body ownership; and eight of the nine studies reported significant reductions in neuropathic pain intensity.

In 2020, Philip D. Austin, one of the authors of this literature review, published the results of a pilot study conducted with other colleagues on the short-term effects of VR on neuropathic pain intensity in people with spinal cord injuries (SCI). In this study, virtual reality was used as a distraction therapy, while participants were asked to move around and observe a nature scene. While noting that more research is needed to show that VR can be effective in reducing spinal cord injury pain in the longer term, the researchers concluded, “We suggest that 3D HMD VR may provide neuropathic pain relief for people with SCI. Given the lack of cybersickness and ease of access, we propose that immersive VR could be a helpful adjunct to current pharmacotherapy.” Regarding the discomfort, let’s be clear that all participants in this study completed the VR interventions, and none reported discomfort from wearing the headset. And interestingly, while the study also considered the level of presence perceived by participants immersed in the VR experience, the researchers were able to determine that this factor was associated with the level of perceived neuropathic pain relief. They also found that short-term pain relief was greater than in the majority of previous studies. Philip D. Austin and colleagues also mention that studies of this type of long-term VR therapy in spinal cord injury pain show that exposures over longer periods of time show greater reductions in pain intensity. They also suggest that other studies using VR applications in combination with cognitive-based therapy and physical rehabilitation may show permanent reductions in pain from such an injury.

“However, given that presence was not an independent factor for pain relief, it is feasible that concerns such as hardware mastery and the effects of the neurological injury on hand movement and control may reduce the immediate analgesic efficacy of VR. Thus, future studies should examine the effects of different types of VR applications such as interactive gaming, interactive injury-specific or non-interactive nature and relaxation-based applications. Furthermore, combining VR with other techniques, such as mindfulness and hypnosis strategies, are shown to reduce levels of pain intensity in several pain conditions and lessen in negative emotions in psychological settings including SCI (Flores et al., 2018).”

As for the mode of action of virtual reality on pain, Austin’s hypothesis agrees with the one most often put forward that depending on the duration of the treatment, two mechanisms may be at work. “Concerning short-term pain relief, VR provides a simple distraction away from pain towards an alternative stimulus—in other words, by hijacking attention, emotion and memory. Here, it has been shown that VR stimuli stimulate brain regions associated with pain modulation. Alternatively, neuroplasticity refers to more long-term pain relief. Here, with repeated use, it is suggested that more long-term changes in function and structure in pain-related brain regions take place. This has been shown in other areas, where, for example, the practice of skills such as playing a musical instrument or a sport affects brain areas involved in proprioception and coordination.” the researcher explained in an interview with Spinal Cord Injury BC.

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In light of all these findings, it appears that for some acute and chronic pain instances, virtual reality is a technology worth investing in, whether for immediate use or to study its possibilities and effectiveness further. Its unparalleled immersive power, versatility, adaptability and accessibility make it a remarkable cutting-edge technology to replace or complement other approaches used to date in pain management. When medication is a problem, VR represents an alternative of choice that every patient, big or small, should be able to benefit from.

It has been shown to be effective in the treatment of acute pain, and there is no doubt that it is of value in the pediatric hospital setting. Studies on its relevance and effectiveness in the treatment of chronic pain are encouraging. Given the importance of this health problem worldwide and the need to offer patients new personalized and multidisciplinary therapeutic solutions that give them a sense of long-term control over their condition, it is clear that the exploration of the vast potential of virtual reality must be strongly encouraged in the years to come.

Author:
Catherine Meilleur

Communication Strategist and Senior Editor @KnowledgeOne. Questioner of questions. Hyperflexible stubborn. Contemplative yogi