The use of Virtual Reality (VR) technology to enhance distraction is a relatively new approach to acute pain management. Although definitions of VR distraction in the literature vary considerably, most VR interventions involve a human-computer interface in which the user interacts with a responsive, multi-sensory virtual environment. VR applications typically utilize a head-mounted wide-angle display and headphones to present the virtual environment. The user interacts with the virtual environment by manipulating a joystick or mouse, or via head- or hand-motion-sensitive tracking devices, resulting in a sense of being more or less “present” in the virtual environment17,19
. VR distraction is presumed to affect pain perception by competing for finite attentional resources and by blocking external stimulation associated with the real environment and the painful stimulus20
In their 2005 review, Wismeijer and Vingerhoots identified 10 studies of VR distraction for analgesia involving a total of 108 participants. Although they documented encouraging analgesic effects for VR distraction for a wide range of medical procedures and laboratory pain, the findings were limited by the small samples (6 of the studies were case studies; two involved 7–12 subjects) and methodological weaknesses20
. More recent, larger scale studies provide additional support for the effectiveness of VR analgesia for cold pressor pain in children3
and burn patients ages 9–4012
Despite evidence of the efficacy of VR- distraction, uncertainty about the real-world value of VR distraction remains due to the concern that the distractive properties of VR conferring it such success may attenuate with repeated exposure. Because distraction interventions are thought to work by competing for attention otherwise directed towards the painful stimulus, the analgesic effect observed may diminish with repeated exposure as the novelty of the VR decreases10,15
. Infants, for example, will show a decrement in orientation toward a distractor after repeated exposure to the stimulus13
This process, known as habituation, has been understudied in the VR literature. Only a few investigators have exposed participants to more than one VR distraction trial. Hoffman et al. implemented VR distraction in seven burn patients during three daily physical therapy sessions11
. Pain ratings were significantly lower in the VR condition relative to baseline. More importantly, a within-subjects analysis of this effect showed that pain reductions did not diminish over the three trials. In a case study of a 32-year-old male burn patient, Hoffman et al. showed significant reductions in patient ratings of time spent thinking about pain, pain bothersomeness and unpleasantness, worst pain, and average pain during a VR condition relative to baseline, which were maintained over five daily physical therapy sessions10
. In a second case study, Hoffman et al. showed similar reductions in pain and anxiety during a VR condition relative to another active distraction condition in two male youth9
. Repeated VR exposure was only reported for one patient, whose pain ratings remained lower during the VR condition, but to a lesser degree than in the first exposure. However, these findings are difficult to interpret because the VR and non-VR conditions were administered during different clinical procedures each day. To our knowledge, there are no published laboratory studies of repeated exposure to VR distraction.
While the findings of Hoffman and colleagues are significant, the case study nature and limited sample size of these studies substantially limits the generalizability of the findings. Thus it is important that the hypotheses and results of the aforementioned studies be tested in a larger-scaled, controlled experimental design. The present study examined the effects of distraction via VR technology over eight weekly trials with a larger sample size than has been reported in the literature, and in a controlled laboratory environment.