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VR for Pain Distraction

Case Study: Snow World and Mobius Floe

Introduction

There’s a widely held belief in the VR community that virtual reality can be used for just about anything. It expands upon the laws of science, allowing humans to do things that were never possible in the real world- whether it’s traveling to the virtual streets of Chiba City, Japan from our couches- or allowing a paraplegic to experience running along a meditative trail for the first time in years. In the words of Jeremy Bailenson, “VR is an experience generator.” It allows us to do things that are impossible in the real world. We can allow users to experience just about anything in virtual reality due to the incredible advancements made in computer-assisted design (CAD), sound design, haptics, hardware, processors. All of these technological advancements over the course of history have allowed us to land at virtual reality as a feasible medium for, well, whatever we want it to be.

“VR is an experience generator. Because it is a digital medium, anything we an imagine seeing or hearing can be easily generated in a VR environment.”

— Jeremy Bailenson, Experience on Demand

But on to the topic of this paper- pain distraction. There is scientific evidence that suggests virtual reality can help distract people from pain. This paper will examine both Snow World and Mobius Floe, as well as the process the designers went through to make the experiences optimal for their intended users- patients struggling with chronic pain e.g. burn patients.

Snow World (http://www.vrpain.com/)

One of the most well studied clinical Virtual Environments (VE) is “Snow- World.” In 1996, Hunter Hoffman and his colleagues developed a VE for burn patients known as “SnowWorld,” which produces the illusion of flying through an icy canyon with a frigid river and waterfall, as snowflakes drift down. Patients were able to throw snowballs at snowmen and navigate through an environment that depicted a cool and serene world. (Gold et al., 2005) SnowWorld is still undergoing development today, finding new ways to improve it’s already impressive results using modern technology.

SnowWorld was built for people struggling with chronic pain, specifically burn patients- and successfully demonstrated, in spite of some limitations, its feasibility, satisfaction, and innovation for decreasing pain associated with medical interventions. VR methods of pain distraction are based on two significant theories: Gate Control and the limited-capacity of attention. The basic theory behind distraction dictates that attention is diverted away from a noxious stimulus and is instead focused on more pleasant stimuli, resulting in a reduction in the perception and experience of pain. (Hoffman et al., 2000)

Thus, the designers goal for SnowWorld was to distract users from pain while keeping user constraints in mind. In many cases, the user was completely constrained. Thus, locomotion needed to be automatic because the user cannot use their hands or feet to maneuver themselves through the environment. In many cases, the patient is also sedated, so tasks need to be simple enough as not to distress the patient, but also complex enough to distract them from the outside world.

Here is a video showing Snow World being used on soldiers suffering from chronic pain due to burn injuries. Some of the material is a little graphic.

Hoffman also found that immersive VR distraction using SpiderWorld (a VE similar to SnowWorld but… well… involving spiders) resulted in lower subjective pain ratings in two adolescents undergoing wound care for severe burns compared to trials in which they played Mario Kart or Wave Race on a Nintendo without the addition of any VR technology. Another study concluded that VR immersion had been very successful by “the amount of attention (it) drew away from (the) real world and allowing patients to tolerant painful dental procedures” .This early evidence of VR’s clinical viability has led to the development of many studies surrounding the subject of VR for pain distraction, as well as new, yet strikingly similar to Snow World, Virtual Environments.

Mobius Floe - PainStudiesLab

Mobius Floe is a pain distraction game used in clinical VR specifically to treat people suffering from chronic pain. It’s predecessor is SnowWorld which was part of a famous study testing the power of virtual reality on distraction. Going off of a previous statement in this article- this is an expansion off of it’s 1996 predecessor using modern technology and game design techniques.

Initial trials have been promising. In a small clinical trial featuring 40 people — each receiving 60 VR sessions — all but one reported reduced pain. Overall, patients reported 60 to 75-percent less pain than before their VR sessions. Immediately following a single session, patients reported 30 to 50-percent less pain. For comparison, morphine averages around 30-percent pain reduction.

Study: VR twice as effective as morphine at treating pain

According to Gromala et al. (2016), Mobius Floe focused on the following details for clinical viability:

• Cognitive Distraction as a Pain Management Strategy
• Strong Sense of Immersion and Embodiment in Virtual Reality

Mobius Flow focused on the following elements for game design:

• A Journey through a Snowy World — The locomotion experience is entirely automated as to guide the user, allowing them to focus their attention on their surroundings rather than trying to navigate themselves through it.
• The Tutorial Cabin- A place to educate the user from within the VE about how the game works and what their tasks and objectives are. Eases them into the experience.
• Neuron Trees- Negative actors in the environment. Provide a stimulus that the user must look out for/defend themselves from. In my opinion, they are a little scary looking, but they sort of need to be in order to capture the user’s attention.

Neuron Tree

• Projectiles- A tool that the user has to defend themselves. They can throw them at otters or trees in order to complete different tasks from within the world. They allow the user to solve puzzles.
• The Health Points- A barometer for the user’s status in the game. Another point of attention. The user must remain protective of their health points in order to succeed in the game.
• The Otters- Friendly actors in the environment that help to guide the user and provide emotional support. They are also used to help solve puzzles.

Here is a video of Mobius Floe:

Further into the game, players are prompted to complete an n- back memory task where they have to remember the order of the objects lined up in front of them. As they continue further down the guided path, they are then presented with the opportunity to receive a bonus item when they complete a puzzle in the correct order. As the aim to provide pain distraction for as long as possible in one sitting, one of the methods we employed to fulfill this goal is through a procedurally-generated landscape. This ensures that the game does not end before the player has received as much of the pain distraction as they need.

The User Experience of SnowWorld & Mobius Floe

There are some striking similarities between Mobius Floe and SnowWorld. In a previous article, The User Experience of Virtual Reality, I listed out some heuristics for VR. In this article I will address some of those heuristics as well as how these environments meet those heuristics. But first, I want to study who exactly the users are.

User Profile: Patients struggling from chronic pain.

User Attributes:

• Physically constrained — by bandages, casts, and wraps over their appendages. The degree of the users physical constraint varies between participants, so the experiences need to be designed for extreme cases in order to be universally accepted.
• Mentally fatigued- In many cases the users might be under the effect of physiological stress or anxiety, or pain-killers and sedation. This means the experience needs to be especially sensitive towards the user’s mental state- distracting them without overwhelming them.
• In physical pain- The user is experiencing a painful procedure while using the VE- which has the goal of distracting them from such pain. Therefore, the system should implement an environment that helps ease the pain by providing distractions.

“We were worried about simulator sickness because people in the burn ward are already nauseated from their burn meds, as well as from their wounds. We really bent over backward to minimize simulator sickness, and what that meant was the patient follows a pre-defined path through the virtual world, and that really calms things down.” -Hunter Hoffman

Environment Attributes/Visual and Interaction Design:

• A distracting environment- The snowy environment is counter to the burns the user is experiencing. It is cool and serene. The snowy environment is the polar opposite of hot temperatures.
• Distracting tasks: There are a couple of scientifically valid tasks for instilling attention capture/providing distraction. These include n-back tasks and attention switching tasks.
• N-back Tasks — The subject is presented with a sequence of stimuli, and the task consists of indicating when the current stimulus matches the one from n steps earlier in the sequence. The load factor n can be adjusted to make the task more or less difficult.
• Attention Switching tasks — AST is a test of the participants ability to switch attention between the direction or location of objects on screen. In the case of Mobius Floe, this will take the form of the player having to switch their attention between solving puzzles and protecting themselves from Neuron Trees.

“Given that an individuals’ attentional capacity is considered
finite, a distracting task that requires a great deal of the person’s attentional resources should leave little attentional capacity available for processing painful stimuli.” — Diane Gromala

Here are some heuristics that can be used to analyze SnowWorld and Mobius Floe experiences.

• Physically and Digitally Safe — The hardware and software is constrained so that the burn patient will not be caused more pain then they are already in by unnecessary movements or interactions.
• Understandable- The simple objective-based tasks are natural for the user. They are tasks that are simple enough for someone under heavy sedation to understand and accomplish. Mobius Floe even includes a tutorial to help the user understand what to do.
• Aesthetically Pleasing — The environment is “cool” and “serene” and not overly-stimulating. It provides a pleasing atmosphere that distracts the user from a crowded doctor’s office atmosphere.
• Protective of the User’s Wellness- The software is built around the constraints of the user, mindful of the fact they are in pain. It protects them from stress-inducing stimuli in the outside world. Mobius Floe even includes an area that is procedurally generated in case of long procedures.
• Balanced in Comfort and Realism- Perhaps the most important, the software is comfortable enough for a user in extreme pain to use while still providing enough realism to distract them and invoke a sensation of presence.
• Sensitive to the Capabilities of the Medium- Pushes the boundaries of the real world. Takes the user from the hospital bed to a magical winter environment. There are many areas of improvement here, but Mobius Floe does a good job incorporating new actors such as neuron trees.

Conclusion

Snow World and Mobius Floe make for awesome case studies- especially since they were developed almost over 20 years apart yet share the same goal. That is, distracting users from pain. The clinical implications are extraordinary and there are so many directions this software could be taken to provide support for a number of different patients. Other applications include Cognitive Behavioral Therapy (CBT) for people suffering from phobias- and these designs could be extended to help people suffering from any other psychological disorder.

From a user experience design perspective, it is easy to compare the designs of the experiences with the users they are built for. The software was designed in a way that was very mindful of the capabilities of the user. That being said, there are still new ways that don’t even exist yet to help provide more realism without the risk of discomfort. Potential solutions might include eye-tracking or new means of locomotion.

Sources

Bailenson, J. (2018). Experience on demand: What virtual reality is, how it works, and what it can do. New York: W.W. Norton & Company.

Gold, J. I., Kant, A. J., Kim, S. H., & Rizzo, A. “. (2005). Virtual anesthesia: The use of virtual reality for pain distraction during acute medical interventions. Seminars in Anesthesia, Perioperative Medicine and Pain, 24(4), 203–210. doi:10.1053/j.sane.2005.10.005

Gromala, D., Tong, X., Shaw, C., Amin, A., Ulas, S., & Ramsay, G. (2016). Mobius Floe: An Immersive Virtual Reality Game for Pain Distraction. Electronic Imaging, 2016(4), 1–5. doi:10.2352/issn.2470–1173.2016.4.ervr-413

Hoffman HG, Doctor JN, Peterson DR, et al: Virtual reality as an adjunctive pain control during burn wound care in adolescent patients. Pain 85:305–309, 2000

Hoffman, H.G., Garcia-Palacios, A., Patterson, D.R., Jensen, M., Furness, T., and Ammons, W.F. The effectiveness of virtual reality for dental pain control: a case study. Cyberpsychology & Behavior: The Impact of the Internet, Multimedia and Virtual Reality on Behavior and Society 4, 4 (2001), 527–535.
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