NAVR / Looking into pain perception and VR

Out of all the physiological modes of perception, pain or nociception is probably the least favorite sensation for most sane humans on earth. Upon finding a genie in a bottle, agliophobics (people who fear pain) might first wish to never feel pain again. However, if on their way out of the genies cave, a young bat with poorly developed echolocation happens to swoop into their hair, mistaking it for food; they could stumble though a lava pit then continue on their way without even realizing that they have third degree burns all the way up to their knee caps! Pain may not be fun but this scenario illustrates exactly why nociception is one the most vital physiological sensations for human well-being. There are times when sensing pain is very important although, there are also times when nociception can be a real drag. For instance, after someone dips their kneecap in a lava pit, the mechanothermal receptors of the nociceptors immediately jump into action by causing an unconscious autonomic response, sucking the kneecap right back out of the lava but they simultaneously transmit signals through sensory neurons in the spinal cord that zoom up to the thalamus where they are redirected to the somatosensory cortex in the cerebrum (Wikipedia, Nociception) and finally, the sensation of pain erupts into consciousness. But once this important neural synaptic dance is over (in less than a second) and the person is conscious of the fact that they have been burned, hours or even days could pass by and the brain might continue sending messages saying, “Your burning, your burning!”, since severe burns in particular, take a long time to heal . So scientists and doctors have developed quite a few methods that attempt to put a stop to feelings of pain once they are not necessarily needed.

Opioid analgesics like oxycodone or morphine inhibit ascending neural pathways of pain perception and activate descending pathways which relieves pain by preventing the signals sent by the nociceptors from getting to the brain (Freudenrich, 2009). However, these analgesics, used for high levels of pain, are only entertaining for so long until physical addiction sets in and no one likes the distraction of being a doped up drooly-sloth. Thankfully, In 1965, two scientists named Ronald Melzack and Patrick David Wall, came up with the idea that the mind could be distracted from the idea of pain resulting in an actual decrease in the physical perception of pain, they called this the Gate Control Theory (Gold & Mahrer, 2009). The theory suggests that attention, emotion and memory, which are related to the central nervous system, are somehow closely involved with processes related to sensory perception. They called it the Gate Control Theory because it posits that pain signals sent from the nociceptors do not travel directly through the body, instead, they move through special “nerve gates” before the body decides how much awareness should be assigned to the pain sensation. In a way, this is like a white furry mammoth gate keeper standing in front a futuristic laser shielded threshold saying, “Tell me everything about the attention, emotion, and memories that you hold from past lives when you repeatedly dipped your kneecap in that lava pit over there!” and you say, “Well...it felt pretty good”. Then he leans over and sheepishly presses the red button to disengage the laser beams, letting the pain signal continue on up then back down the neural pathway and then the lava dripping from your knee ends up not hurting so bad because you lied to the guard. Scientists have found that the gatekeeper can indeed be fooled into letting one get away with feeling less pain if a tool of distraction is utilized. In a Medical News Today article, a Dr. Butz states that “Research shows a very strong connection between anxiety and pain. Distraction does a great job in decreasing any kind of anxiety that might be associated with the anticipated procedures, so by distracting patients and keeping anxiety at a minimum, procedures tend to go much more smoothly and be much less painful for the child.” During burn patient wound dressing and other procedures, several types of distraction have been used such as, reading books, listening to music, playing video games, watching television, as well as counting and deep breathing (MedicalNewsToday, 2009). However, these traditional forms of distraction are practically ancient when applied to hyper active kids today who are listening to music while uploading live video of themselves to FaceBook as they're stealing third base in a Taco Bell sponsored T-Ball tournament. If a person really wants to create a distraction for themselves these days they would have to shove their head through a rip in space time and immerse themselves in the sights and sounds of Negative Land. But since quantum physicists haven't taken a clue from the sewing machine industry and are taking their sweet time with building hyper dimensional space-time seam rippers, the best distraction device, that cutting edge science has to offer, is the exciting new world of Virtual Reality!

Actually, Virtual Reality technology (VR for short) has practically been around for forty years since the first augmented reality, head mounted display (HMD) system was developed by Ivan Sutherland and Bob Sproull in 1968 (Wikipedia, Virtual Reality). But it was not until the mid nineties that VR grabbed the interest of popular media after the box office train-wreck, The Lawnmower Man, was released in 1992. Virtual Reality systems have yet to be fully implemented and accepted by the mainstream. Even the Virtual Boy VR console system, released in 1995, by the Nintendo Corporation was a flop but doctors and scientists have recently found VR technology to be an effective and promising solution for distraction related pain therapy. This high-tech area of pain management is still very young and not fully understood but positive results have been recorded in a number of case studies. The first evidence that supported Virtual Reality pain management came from a study involving two male burn patients, ages 16 and 17. The two were both put in a situation that compared video games as a means of distraction to Virtual Reality while having their burns cared for. The results showed that both of them experienced a greater decrease in pain intensity, anxiety, and time spent thinking about pain while in the VR environment compared to simply playing video games (Gold & Mahrer, 2009). This was one of the very first case studies so we can be forgiving about the lack of proper detailed documentation but details are very important because the type of VR as well as the fidelity of the VR can have varying affects. A Virtual Reality system could be just a head mounted display (HMD) unit. However, the system could be as complex as a HMD with audio, combined with head tracking so the VR environment changes with the position of the patients head, as well as a control unit with tactile feedback. And higher resolution VR systems will increase the level of believability, causing one to feel that they're actually immersed in another world more-so compared to lower resolution systems.

A recent and much more precise study was conducted in 2008 by at the University of Maryland. This study involved forty-one children who voluntarily participated in a cold pressor pain tolerance experiment where they were distracted, on separate trials, with both a video game played on an flat screen monitor with speakers as well as the same video game except it was played with a VR head mounted display unit with headphones. They played the video game with and without the VR HMD while pain threshold (the amount of time that passed until the child reported pain) and pain tolerance (to total duration of time that the child kept their hand in the cold water) were measured. The results showed that the children's pain tolerance significantly improved when using the VR HMD as compared to playing the came in front of the flat screen display (Dahlquist et. al., 2008). Virtual Reality is an exceptionally effective method for distracting one from pain sensations because it is, in general, a highly immersive experience. Research seems to show that as the immersive qualities of the VR environment increase such as, with the use of HMDs, sound, head tracking, haptics, and higher resolution, a greater drop in pain perception is experienced by the patient. The amount of research that validates VR as a positive form pain management continues grow and attract attention but do neurobiologists and researchers performing these studies really know how all this works?

The answer is...not exactly. Remember that big white wooly mammoth that was the gatekeeper, standing in front of the laser beams? Sure, he was a strange analogy but he was meant to stick out because those guys Melzack and Wall were really on to something with their Gate Control Theory. VR has a strong effect on attention, emotion, and memory and as the Gate Control Theory suggests, these three elements related to the central nervous system also have an effect on nociception. Since VR pain therapy is so new, little is known about the neurobiological processes that are involved, although researchers have managed to figure out a few things. By using functional Magnetic Resonance Imaging (fMRI), scientists monitored the brain while patients were in the midsts of a pain distraction session. They found that cortical areas of the brain that are associated with attention and pain modulation were more active while the person was being distracted while parts of the brain directly related to pain perception, like the thalamus and mid-cingulate, were less active. In more specific terms, the orbiofrontal cortex showed an increase in circulation when pain was present along with a distraction, compared to just pain alone. However, the thalamus and other pain related centers of the brain decreased in activity during a distraction period. Although, they still do not understand the real nitty gritty of what is happening, these findings suggest that the pain modulation gates that Gate Control Theory explained in the 1960's, really do exist.

Although, nociception can seem like it is being overly dramatic about little things like paper cuts, stubbing your toe, or hitting your funny bone on the coffee table, it really comes in handy when it tells you important things like, “Get your foot out of that lava!”. But when it seems to have Alzheimer's by telling you over and over again that something hurts, you can use the power of your mind to distract yourself from the pain or you can use a much more exciting distraction like a totally cool Virtual Reality underwater video game! The field of VR pain therapy might still be very young, but in it's infancy, it has already exhibited a great amount of potential. It has pushed neurobiologists, psychologists, anesthesiologists, and other professionals to probe into previously unexplored areas of pain perception. Virtual Reality could some day be thought of less as a form of entertainment and more so as a method for attending to pain on a daily basis, reducing the need for pharmacological drugs.






Works Cited
Dahlquist, Lynnda M., Karen E. Weiss, Lindsay D. Clendaniel, and Emily F. Law. "Effects of Videogame Disraction using a Virtual Reality Head-Mounted Display Helmet on Cold Pressor Pain in Children." Journal of Pediatric Psychology Advance Access (2008).

Freudenrich Ph.D., Craig. "HowStuffWorks "Introduction to How Pain Works"" Howstuffworks "Health Channel" 10 May 2009 .

Gold, Jeffery I., and Nicole E. Mahrer. "The Use of Virtual Reality for Pain Control: A Review." Current Pain and Headache Reports (2009).

"Nociception -." Wikipedia, the free encyclopedia. 10 May 2009 .

"Virtual reality -." Wikipedia, the free encyclopedia. 10 May 2009 .

"Virtual Reality Games Used To Distract Young Burn Victims From Pain And Anxiety." Medical News Today: Health News. 2007. Nationwide Children's Hospital. 10 May 2009 .