Using Virtual Reality (VR) to Reduce Mobility-Related Anxiety in Lower-Limb Prosthesis Users (LLPU) - Lower limb prosthesis users (LLPU) experience more falls and greater fear of falling compared to the community-dwelling population without amputation, with most LLPU reported having fallen at least once in the past year. Reducing the risk of falling would increase physical activity levels and reduce medical costs and incidence of death in LLPU. The association between self-reported poor balance confidence with low levels of physical activity after lower limb amputation highlights balance confidence as a potential target to improve physical function and reduce falls in LLPU. Typical exercise-based interventions attempt to improve physical activity but fail to address the complex interaction between mobility and psychosocial factors, failing to improve balance confidence in LLPU. Leveraging evidence-based interventions that use virtual reality (VR) to administer ‘exposure therapy’ treatment for post-traumatic stress disorder in soldiers in combination with laboratory-based methods of inducing a postural threat that elicits mobility-related anxiety offers an untapped mechanism to improve balance confidence in LLPU. The purpose of this project is to determine the utility of VR-based exposure therapy to reduce mobility-related anxiety in LLPU. To accomplish this goal, LLPU and able-bodied controls (young and older adults) will be exposed to high elevation VR settings across time and undergo repeated exposures to mobility-related anxiety in VR settings. In Aim 1, I will reveal how able-bodied controls respond across time and with repeated exposure and in Aim 2, I will determine how LLPU respond to mobility-related anxiety across time and with repeated exposure in anxiety inducing VR settings, and their responses compared to able-bodied controls. I will conduct a cross-sectional investigation including LLPU (n=12) and able-bodied controls (n=24, n=12 young adults, n=12 older adults). Participants will be fitted with a commercial (HTC Vive, version 2.0, Bellevue, WA) wireless head-mounted display presenting a wooden walkway (Unity 3D) matched to a real-world plank (0.4x5.2m). Participants will be instrumented with four position trackers (HTC Vive, version 2.0, Bellevue, WA) and a heart rate/electrodermal activity monitor (Empatica E4, Cambridge, MA). Participants will walk for 1 minute at ground level to familiarize themselves with the VR setting before being transported to a high elevation (15-m elevation) VR setting for the first exposure. Participants will walk at the high elevation VR setting for 5 minutes before being transported back to ground level, where they will walk for another 1 minute at the ground level, representing the ‘wash-out’ period, before being transported to the high elevation VR setting for a second exposure. After each walking bout, participants will complete assessments of their levels of anxiety and confidence during the most recent trial. Results from this study will reveal how LLPU adapt differently to mobility-related anxiety induced with a high elevation VR setting compared to healthy controls across time and repeated exposures. Knowledge gained from this project will enable researchers and clinicians to understand how LLPU respond to mobility-related anxiety compared to able-bodied controls. Completing this project will identify targets for intervention and individualized rehabilitation in LLPU. Adopting VR-based exposure approaches in rehabilitation methods will reduce fall risk and increase activity levels, which will consequently improve balance confidence and community ambulation in LLPU.
