Virtual Reality (VR) is a burgeoning and novel technology which is seeing a rapid uptake in healthcare; it is designed to confer the experience of entering a virtually generated environment that is immersive. VR has been used to great success in various clinical settings – from the setting on intravenous lines or obtaining blood samples in paediatric patients, to addressing the pain imposed during burns and dressing changes, as well as in post-surgical states, which are characterized by variable degrees of pain and anxiety.
The VR experiences are typically facilitated in two ways – via a brain-computer-interface or a human-computer-interface. Most commercial VR devices such as the Samsung Gear VR or Oculus Rift leverage a human-computer-interface that is delivered through a head-mounted-display (HMD). This HMD is further enhanced with built-in binaural headphones to deliver auditory stimuli, as well as an integrated or external trackpad and/or joystick to allow the virtual environment to be seamlessly navigated. Within the virtual environment, users are able to deploy two types of movement – orientational and positional. The user’s orientation of the head is tracked with in-built accelerometers and gyroscopes. Positional movement is enacted via external sensors in a pre-defined space relative to the HMD’s position – this feature is exclusive to advanced VR systems such as the OptiTrack and Playstation VR. Newer VR companies are aware that the requirement to mount external sensors in an enclosed space is a deterring factor for consumers, and have integrated in-built cameras with Simultaneous Location and Mapping (SLAM) algorithms to register static features within a room (e.g., a television set or a table-lamp) in order to provide their users with positional tracking.
Immersion and Presence
Before we discuss the applications of VR in healthcare, it is prudent to understand the determinants of success in simulating a virtual environment. Two of these – immersion and presence, are fundamental factors which are taken into consideration in this regard.
Immersion is the extent to which one feels present in a virtual environment. It is a subjective characterization of the VR technology in its capability to deliver an inclusive and extensive environment and the illusion of reality to the participant. Presence, on the other hand, is the perception of being within the virtual environment. In other words, it is a consequence of immersion and spans the cognitive, psychological, and perceptive domains. Factors which affect the degree of immersion and presence include, but are not limited to, haptic feedback, the presence of sound that is synchronised with the visual images, the representation of the user’s body in the virtual environment (e.g., hands) as well as the amount of interactivity achieved.
The Mechanisms of VR Therapy
VR therapy has been shown to alleviate pain and anxiety in acute settings such as in the changing of burns dressings, hydrotherapy for chronic wounds, phlebotomy in children and acute interventions such as cystoscopies and epidural injections. How does a virtual environment produce analgesia and anxiolysis?
In 1965, Melzack and Wall proposed the Gate Control Theory which stipulates that the amount of attention given to pain as well as the emotions and memories associated with it contribute to the overall interpretation of pain. Two decades later, McCaul and Malott proposed that we have a finite capacity of cognitive resources for our attentional span and that these finite resources must be recruited in order to address a noxious stimulus and subsequently perceive pain. Based on this, it follows that the relocation of one’s attention from a noxious stimulus (e.g., an injection) to a non-noxious stimulus (e.g., virtual snowballs being thrown at the individual) would impose an economic burden on the individual’s finite cognitive resources. The division of resources between the two stimuli would mitigate the perception of pain. Distraction therapy is not a novel discovery – since time immemorial, a panoply of tools such as whistles, bells, songs, cartoons and even conversation have been utilized by healthcare providers in order to distract their patients from impending pain. VR takes distraction therapy one level higher by maximising immersion and presence – elements which have only been superficially skirted by older tools of the trade.
Does VR Therapy Work?
Now that we have understood the mechanisms underpinning VR therapy, we should begin a thoughtful analysis of its purported merits. What does the scientific literature say about VR therapy? Is it as good as traditional pharmacotherapy (e.g., opioids)? Does it have side-effects like other pain-relief strategies? What about health-economics; is it cost-effective? What outcomes can it improve other than pain? These questions will be addressed in my next article, where I will also share what we at Biorithm are doing with VR.