Pre-Exposure Cybersickness Assessment Within a Chronic Pain Population in Virtual Reality

Virtual Reality (VR) is being increasingly explored as an adjunctive therapy for distraction from symptoms of chronic pain. However, using VR often causes cybersickness; a condition with symptoms similar to those of motion and simulator sickness. Cybersickness is commonly assessed using self-report questionnaires, such as the Simulator Sickness Questionnaire (SSQ), and is traditionally conducted post-exposure. It’s usually safe to assume a zero baseline of cybersickness as participants are not anticipated to be exhibiting any sickness symptoms pre-exposure. However, amongst populations such as chronic pain patients, it’s not unusual to experience symptoms of their condition or medication which could have a confounding influence on cybersickness symptom reporting. Therefore, in population groups where illness and medication use is common, assuming baseline is not necessarily desirable. This study aimed to investigate cybersickness baseline recordings amongst a chronic pain population, and highlights how deviations from an assumed baseline may incorrectly infer adverse effects arising from VR exposure. A repeated measures study design was used, in which twelve participants were assessed pre and post VR exposure via SSQ. Significant differences were found between actual and assumed pre-exposure baseline scores. Furthermore, we found significant differences between actual and assumed increases in cybersickness scores from baseline to post exposure. This study highlights that clinical sub-populations cannot be assumed to have a zero baseline SSQ score, and this should be taken into consideration when evaluating the usability of VR systems or interventions for participants from different demographics

Visual stimulus disrupts the spatial localization of a tactile sensation in Virtual Reality

Phantom limb pain is a neuropathic condition in which a person feels pain in a limb that is not present. Cognitive treatments that visually recreate the limb in an attempt to create a cross modal interaction between vision, and touch/proprioception have shown to be effective at alleviating this pain. With improvements in technology, Virtual Mirror Therapy is starting to gain favor, however, there are currently no applications that utilize passive touch in the same way non-virtual reality applications do. This paper investigates whether a visual stimulus can relocate a tactile stimulus to a different location using principles from the rubber hand illusion and mirror therapy. We demonstrate that a displaced visual stimulus in virtual reality can disrupt accurate spatial perception of a physical vibrotactile sensation however the effects are small and require further investigation

The use of embedded context-sensitive attractors for clinical walking test guidance in virtual reality

Virtual reality is increasingly used in rehabilitation and can provide additional motivation when working towards therapeutic goals. However, a particular problem for patients regards their ability to plan routes in unfamiliar environments. Therefore, the aim of this study was to explore how visual cues, namely embedded context-sensitive attractors, can guide attention and walking direction in VR, for clinical walking interventions. This study was designed using a butterfly as the embedded context- sensitive attractor, to guide participant locomotion around the clinical figure of eight walk test, to limit the use of verbal instructions. We investigated the effect of varying the number of attractors for figure of eight path following, and whether there are any negative impacts on perceived autonomy or workload. A total of 24 participants took part in the study and completed six attractor conditions in a counterbalanced order. They also experienced a control VE (no attractors) at the beginning and end of the protocol. Each VE condition lasted a duration of 1 minute and manipulated the number of attractors to either singular or multiple alongside, the placement of turning markers (virtual trees) used to represent the cones used in clinical settings for the figure of eight walk test. Results suggested that embedded context-sensitive attractors can be used to guide walking direction, following a figure of eight in VR without impacting perceived autonomy, and workload. However, there appears to be a saturation point, with regards to effectiveness of attractors. Too few objects in a VE may reduce feelings of intrinsic motivation, and too many objects in a VE may reduce the effectiveness of attractors for guiding individuals along a figure of eight path. We conclude by indicating future research directions, for attractors and their use as a guide for walking direction

The simulator sickness questionnaire, and the erroneous zero baseline assumption

Cybersickness assessment is predominantly conducted via the Simulator Sickness Questionnaire (SSQ). Literature has highlighted that assumptions which are made concerning baseline assessment may be incorrect, especially the assumption that healthy participants enter with no or minimal associated symptoms. An online survey study was conducted to explore further this assumption amongst a general population sample (N = 93). Results for this study suggest that the current baseline assumption may be inherently incorrect