Using Virtual Reality to Treat Pain

We speak with physiotherapist, Dr. Daniel Harvie [B Physio (hons), M Musc & Sports Physio, PhD, Postdoctoral Research Fellow] about the use of virtual reality in the treatment of pain. Dan discusses the current uses of VR in acute pain, potential uses for persistent pain, and where he sees the future of VR heading.

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You can learn more about Dr. Daniel Harvie on Twitter or LinkedIn

View Episode Transcript

Katie Yamamoto               

This is Episode 32 of Functional First podcast where we speak with leading experts in the field of functional health. I’m Katie Yamamoto from Functional Media, and today I’m speaking with Dr. Daniel Harvey on virtual reality.

Okay, can we start by having you introduce yourself?

Dr. Daniel Harvey             

Yeah, sure. Firstly, thanks for having me. And thanks to the Functional First team for coming on the Pain Revolution, it’s great to have your media skills here. I’m Dr Daniel Harvey, I’m a National Health and Medical Research Council funded early career research fellow at Griffith University. So I’m in a research group called the Hopkin Center, which sits in the Menzies Institute for Health Queensland. So I’m a physiotherapist by background training at the university off South Australia. So that the history there people like Geoffrey Maitland and more recently, people like Mary McGary in Mark Jones, who I did my master of musculoskeletal and sports physio with. It was at the end of that course that was became really interested in pain, and Lorimer Moseley came to the university around that time and I felt like fate. So I signed up for a PhD and have been in pain ever since.

Katie Yamamoto               

And tell us about what you were doing for your PhD.

Dr. Daniel Harvey             

Yes, sure. So my PhD followed on from Lorimer’s imprecision hypothesis paper, which was was a hypothesis around the idea that pain might be learned through associative learning mechanisms. So particularly classical conditioning. So just in the same way that Pavlov’s dogs learned to salivate to the sound of a bell the question post was. Could pain be a learned response to the things associated with pain or injury or nociception? So basically, it posited that nociception was a kind of unconditioned stimulus and pain was the response that was innately linked to that. So unconditioned stimulus and an unconditioned response. So that so the idea or the question was: Could things associated with nociception become conditioned stimuli capable of evoking those responses normally exclusively linked to nociception. So my PhD set out to investigate that hypothesis and we did some studies that provided some support for that and also raised a whole lot of questions around it.

Katie Yamamoto               

And you’ve been interested in virtual reality. Can you tell us about that?

Dr. Daniel Harvey         

I have. Yes. So I became interested in virtual reality in investigating that hypothesis. We thought If pain can be a learned response, then the thing that’s most likely going to be linked to this movement, because movement is often the thing that is, that is so linked to pain. So we thought that, you know, almost in neurons that fire together, wire together, sort of a linking might result in movement or the kinesthetic signals associated with movement. For that, they might be able to become contributors to pain or triggers of pain.

So the way we’ve thought to investigate that was to make it look to people who were in pain, they could look to them like they were moving more or less than they actually were. And we hypothesized that their pain would come on sooner or later, depending on whether the visual signals suggested they were moving more or less than actually were.

And so we investigated that people with neck pain and we found that when it looked to them like they were moving more, their pain came on a bit sooner, and vice versa. When it looked to them like they were moving less, they’re able to move further before the pain came on, and we explained that within the framework of the imprecision hypothesis.

Katie Yamamoto               

What’s the history of using VR therapeutically for pain management?

Dr. Daniel Harvey             

That’s a great question. So it’s mostly so far been used in acute pain. Management really is a sophisticated form of distraction, so that’s been used a lot in burn  care. So for distracting people providing anesthesia during wound cleaning type procedures, more recently it’s been explored in procedures associated with labor, and people who are giving birth or about to give birth. So there’s been a whole heap of acute pain areas that have that have explored that.

Katie Yamamoto               

And then what about for persistent pain?

Dr. Daniel Harvey             

Yes, for persistent pain, it’s a lot more complicated. Distraction isn’t a practical strategy for tackling chronic pain in the long term, although some people might find it as a useful retrieve for short periods of time.

So this is something we really working through at the moment. We don’t have all the answers on it, but there are a few possible areas that we can move forwards with in that space.  We know that things like mindfulness can be, can be helpful for some people and using virtual reality as a sophisticated form off meditation might be one path forward. We can superimpose visual imagery on top off normal meditation procedures. Put people in nice environments, those sorts of things. So that’s one avenue. Functional training exercises, another potential avenue. But the question we always have to ask ourselves is, does it add anything to do this in virtual reality compared to doing it out of virtual reality? We don’t want to use virtual reality just for the sake of the novelty of it.

So that’s one idea that we’re working through a the moment. Another is to use illusions like the illusions I was talking to you before. So we know that the brain and the way it encodes the body can shift after an injury. And a question we have is can we tackle those in some way using allusions or some form of virtual reality can be target cortical representations off the body. This some evidence, of course, that’s that illusions might be helpful from as far back as mirror therapy for phantom limb pain. Those sorts of things. More recently, we find when we do illusory stretches off arthritic fingers or knees, we find that people get at least temporary analgesia from those things and they must be working. They must be having that analgesic effect via the brain. So we’re also working through what sort of illusions can we do in virtual reality? And might they be useful. Our earlier and so far, unpublished attempts that that haven’t found a useful way forwards there? But there are so many possible ways that we can go down that track.

Another possibility off the top of my head is we know that teaching people the science of pain can be a really useful strategy. And, something called immersive education or gamified education might be another way to get across some of those messages. So that’s something that’s a space that we’re moving into at the moments and something we’re doing some development in and even gamification of aspects of rehabilitation might be useful for assisting motivation, adherence, encouraging people to get going. So I’m always thinking do we need to do this in virtual reality? Does this add something? Try to use that as a guide to working out where to go, you know.

Another thing we think about is you know, what body areas might be best suited for virtual reality and that seems to be dependent on the technology that’s available at the time. So at the moment it’s quite difficult to get your whole body into a virtual space where you can interact with all parts of your body and see a whole body. At this point in time, even the cheap virtual reality headsets, though I think at least, are well adapted for neck movements. So that’s where I focused so far because the technology lends itself to neck related rehabilitation.

Katie Yamamoto               

Do you find that cost will be a barrier to be using this type of technology for people?

Dr. Daniel Harvey             

I think cost will be something of a barrier, perhaps not in the West, particularly as the prices have been coming down dramatically to the point where you could buy ah, stand alone virtual reality headset in there for about $300. Of course, you can get more sophisticated to the point where you also need a $4000 computer with high end graphics processing to drive it.

But you know, so all of those things do need to be considered as well in the process of developing this sort of stuff.

Katie Yamamoto               

Do you envision VR being used clinically by clinicians and patients?

Dr. Daniel Harvey             

Yeah, I do. I do envision that. I don’t know when that will be. When we talked to clinicians, we really find that they want to see that there’s some benefit from using virtual reality as opposed to doing strategies outside of virtual reality. And they want to see at least a base level of evidence. And we’ve asked that to a lot of clinicians in Australia now. And that’s the answer that we get consistently, which I think is a credit to the clinical community here because I think that’s spot on.

Corey Persic                     

What is it about the visual part of virtual reality that is, compared to other systems like presumptive, it just supersedes it and leads to that you pain reducing effect.

Dr. Daniel Harvey         

Yeah, yes, so the question there really is why is vision such a powerful modulator off our experience and I think that really comes down to the precision. So how much information vision gets us and how reliable it is as an indicator of what’s really going on in the world. And you know something like 1/3 of our brain is dedicated to visual processing.

So I think that gives it particular power as potential mediator of treatment effects, I guess. Yeah, when I think about the hype around virtual reality, I don’t just think about hype in terms of using virtual reality in the rehab space. In fact, I’m not sure there is that much hype for using virtual reality in the rehab space at this point. But even in the gaming space and other things, it still has a lot of limitations at the moment, like it’s completely anti social in the sense that when you put on a set of headsets, you really don’t block out what’s happening around you to the point where even if there’s nothing blocking your ears, you will tend to not notice.

The fact that someone is right next to your trying to talk to you. It’s really antisocial. I think when you when you compare that to other forms of gaming, much more interactive. You can see what the other person’s doing. But we are getting to a point where even with the standalone headsets, you can have second screens that show in real time what the person is seeing. We’re getting to a point where you can be in a virtual space with other people also in in virtual spaces. Not necessarily even in the same environment.

I think it will transition from a point where it’s antisocial to where its potentially even pro social if it enables you to connect to more people in more spaces. There’s also elements that we have to think about in rehab, like safety, balance, because people lose a certain amount of awareness off the real world. So you have to factor in safety into that scenario as well. So it’s a little bit of hype, but I think it’s tempered by some of the limitations that we see in the technology at the moment.

Katie Yamamoto               

Where would you like to see the future of VR going?

Dr. Daniel Harvey             

Well, I’m passionate about seeing people with chronic pain get better outcomes. So if virtual reality is part of that, then great. That’s gonna help my research career progress because that’s the track that I’m on. But if we find that there are much better strategies outside of virtual realities and virtual reality is a direction of research that dies, that’s fine with me, because that’s not what I’m here for.

But what the track that I’m on, is looking at can we get some active based approaches embedded in virtual reality in a way that facilitates treatments that we know are effective or that enables treatments that we don’t yet know are effective. So I guess in that I’m hoping that opens up new possibilities that help people with persistent pain problems.

Katie Yamamoto               

And can you tell us about the VR that you use in the brain bus? And how you use that to explain chronic pain to people or what’s happening with chronic pain?

Dr. Daniel Harvey             

Sure, yes. Oh, so basically, the brain Bus is there to get people excited about the brain, how perception works, and then linking that to pain as a complex perception like any perception. So in the case of virtual reality, sometimes it can be a little bit tricky to make that link. It’s sometimes a little bit easier with the other, with the illusions like the rubber hand illusion and some of the other illusions.

But basically, virtual reality is an illusion. Its almost so convincing you don’t realize that is an illusion. But the fact that you can put a two dimensional screen in front of you and completely feel like you’re somewhere else tells us something about the way the brain works, the way it constructs out reality from sensory information, from past experience, from all other sorts of things. So we use it to try to disrupt people’s sense of how perception works, how the realities constructed. And then we link that to pain is also a complex perception that depends not just on sensory information but all other sorts of things.

You know, another way of thinking of perception of our conscious reality is that it is sort of an illusion. It’s a projection off a brain based on all the information that it that it can gather and put together and virtual reality is a really neat way of showing how you can feel like you’re in another reality that is completely fake.

Corey Persic                     

Is there any research with augmented reality, or is it too early for that? Because I know that the tech is a little bit slower on that side.

Dr. Daniel Harvey             

Yeah, or augmented reality is something that I talk about a lot with my virtual reality collaborators.

Until recently, the most sophisticated form of that was the Microsoft Hololens, and we’ve sort of had it in the back of their minds that it’s a potential new direction for us. But in its current state, it’s been quite limited. So the actual screen sizes are really quite small, which means your field of view in augmented reality is limited to a box in front of you. The potential benefits of augmented reality is augmented reality doesn’t block out the entire world, so you can still interact with real spaces while having additional projected objects in in the real world, projected into the real world.

Um, so there’s a lot we can potentially do with that. For example, would be gamifying a gym program, scores, feedback. The objects that you interact with could be altered in the way that they appear. There’s also the things we can do that also, without being concerned so much about the safety issues of being in a virtual space. So watch this space.

But the limitations of augmented reality are slowly disappearing. There’s been some recent new releases. The Magic Leap has been one. A new version of the Microsoft Hololens has just come out. Haven’t caught up with the specifications of that. But the field of view is getting broader, capabilities are expanding. Yeah, watch that space

Corey Persic                     

I just had a question about So, do you change the degree of someone’s moving their head – the gain.

Dr. Daniel Harvey             

I guess, Yeah.

Corey Persic                     

On how frequently would that have to happen for it to be a consistent effect outside a session of virtual reality?

Dr. Daniel Harvey             

Yes, I guess my first answer to the question of how often would people have to train with an increased gain value to get a therapeutic response outside of that? Well, we don’t know that it can have a therapeutic value outside of that, you know, weaken change pain in real time by changing gain values. My first attempt at using altered gain values as therapy hasn’t showed a sustained benefit. It is not necessarily to say that there’s not a way of using that for a therapeutic benefit, but our first attempt have shown that it doesn’t create a therapeutic benefit.

Yeah, so we’re working out whether to continue with that line of research or switch focus.

Katie Yamamoto               

Do you have other areas of interest with research?

Dr. Daniel Harvey             

Yeah, I guess. I guess broadly, I’m interested in in treatment approaches that target the brain, which could be anything from education through to things we can do with virtual reality.

I’ve also become interested in sensory training techniques, particularly the idea of tactile acuity training. We know that often people persistent pain lose a certain degree of their ability to localize where sensations are coming from. And we can measure that with tests like the two point discrimination test to a certain degree. So I’ve become interested in the idea that perhaps we can retrain that ability, and with the possibility that we can, we can target the brain with that strategy and reduce pain.

One of the limitations with that approach that’s come out in the literature is people need to do a lot of repetition, a lot of hours training that, and usually that requires a second person. So let’s say that you’re doing tactile acuity on a hand, you might draw a grid that has a number of numbers in it. Take a picture, and then a family member or therapist will touch one of the squares of the grid, and the person in pain will look and say “I think that was a three. And I think you touched me with the tip of the pencil” and that the therapist will give feedback and say “close it was actually the square next door – number two, and it was the rubber side of the pencil.” So they’re getting feedback about where sensations are coming from and also the quality of the sensation. So we think of that is getting better  at discriminating that sensory information.

We don’t exactly know how that links to pain, but we know that in order to localize and  discriminate sensations, you actually need a lot of inhibition, so you need to, you know our brains are  always being hit with a mess of sensory information, sensory signals, and it has to filter that, it has to inhibit information. It’s less relevant in highlighting information that that it’s more relevant.

So in that process of training, we think perhaps we get better at localizing through to and discriminating by getting better at inhibiting. So maybe that’s a way of training inhibition. But back to the limitation of that in requiring a lot of hours of training and a second person, it’s been reported in the literature that patients feel guilty taking their the family members time, have trouble coordinating schedules, and at the end of the day, not enough training is done to get a therapeutic effect.

So we’ve had this idea to create a device that people can take home based around rows off mobile phone vibrators actually that connect wirelessly to a tablet. People can play games whereby they could better it at localizing sensations. So that’s another direction that I’ve become interested in and have a PhD student, Nicole Tough, has been working really hard on that. Make it fun and engaging. Um, we look forward to finding out whether that also a has a therapeutic effect.

Katie Yamamoto               

That’s really cool

Dr. Daniel Harvey             

People, So I think it feels good. You know it feels a bit like a massage. We’re not using it as a massage, but for that reason, people seem to like to use it so. Also looking at whether we can use it as a test do. I don’t identify whether people do have a decreased ability to localize, to discriminate and thinking that that might be a biomarker for whether people have changes in the somatosensory cortex that might relate to their that problem. A lot of ifs in that that way of thinking. But we hope that a device like this that makes it a bit easier, hopefully more reliable to test. And that makes testing whether it has whether this approach has a therapeutic benefit, easier. We had that those that might help us progress our knowledge and whether that it’s going to be useful way forwards.

Corey Persic                     

Are there normative values for two point discrimination?

Dr. Daniel Harvey             

There are some normative values out there. They differ a bit from study to study in their some slight differences across ages and genders, that data can be found. I had an honours student to a systematic review of that now, four years ago that I’m sorry hasn’t made it to publication, but hopefully it will soon enough. Um, but still, we know that the best comparison if you haven’t available to is the opposite side of the bodies have been once found that published that some years ago. I say, If it’s not a bilateral problem and you’re trying to gauge whether they might be some changes in tactile acuity than a comparison to the opposite side of the body is a good way to go.

Katie Yamamoto               

What about for areas where you don’t have another side like your back?

Dr. Daniel Harvey             

Yeah, that’s a good question. If there’s an unaffected area, proximal or distal, you can use that as a bit of a guide. That might be a bit less reliable because tactile acuity differs so much across the body. But you can use that as a bit of a guide, and if you wanted to, you could go to normative values to say how much difference you might expect between those different body areas. There’s the odd person where the changes are really big, and in those cases you could effectively using normal values of your own. You can build off a bit of a picture of what’s normal yourself in those extreme cases. Probably make a fair judgment call based on those other references.

Corey Persic                     

You mentioned that could be used as a biomarker. Are there other biomarkers for pain that you think show promise?

Dr. Daniel Harvey             

Yeah, great question. So I guess that, in recent years, there’s been a whole range of quantitative sensory tests that I think will show some utility as time goes on in identifying the mechanisms underlying people’s pain states. I  guess the most interest in that area has been around identifying who might respond to different pharmaceutical modalities. Um, so, yeah, I think the potential for that might be a lot broader,  but at the moment, we need quite expensive, quite sophisticated equipment to do reliable and valid quantitative sensory testing. But that that’s something to look out for as well, I guess.

Katie Yamamoto               

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