EAGER: Enabling Virtual Reality for Aquatic Rehabilitation of Persons with Disabilities

由于虚拟现实(VR)技术(例如，带有全身跟踪系统的头盔显示器)通常不能在水下使用，水上VR将对用户交互产生什么影响大多是未知的，潜在的重要水下应用，如基于泳池的物理康复仍未实现。总的来说，关于水上虚拟现实的研究很少，而且没有一项工作调查过它对残疾人的影响。先前的研究表明，VR增强的康复可以提供许多好处，比如通过沉浸式游戏增加动力，以及在安全环境中练习的能力，但VR尚未应用于水上康复的实践。在这项探索性研究中，PI将寻求为水上VR确定有效的系统和交互方法，以保持残疾人的康复动机并最大限度地提高运动成绩，特别是对于通常有本体感觉和平衡缺陷的多发性硬化症(MS)患者。PI的初步工作表明，视频透视显示、通过惯性测量单元进行身体跟踪以及通过光学跟踪进行头部定位将实现有效的水上VR系统。PI的假设是，水上VR将使目标人群的成员能够比在陆地上更好地进行锻炼。如果这一假设得到支持，该项目将代表着朝着虚拟现实普遍使用这一重大挑战迈出的关键一步，特别是将使人们更深入地了解虚拟现实作为康复媒介的有效性。为了验证他的假设，这项研究将包括两个推力。其中之一将寻求确定实现水上虚拟现实的可行系统方法。在前期工作中，PI设计了一个由现成组件的新颖组合组成的原型系统。一款防水智能手机被绑在潜水面罩上，以实现虚拟水下环境的3自由度跟踪立体视图。另一款防水智能手机被安装在用户的胸前，可以进行三自由度身体定位跟踪、出拳检测和触觉反馈。游戏的虚拟声音是通过一副防水耳机传递的，这也允许在水下听到真实的声音。本项目的另一个重点将通过一系列实证研究来确定水上VR如何影响人体康复练习的表现，考虑到水上康复相对于陆上康复的已知优势，这里的工作假设是，与陆上虚拟康复相比，水上VR将使残疾人体验到更少的疲劳，更好地保持平衡，运动时间更长，阻力更大，而且与传统的水上康复相比，它还可能提高动力。在前期工作中，PI开发了Shark Punch，这是一款水上VR游戏的原型，玩家必须在真实的水下环境中与虚拟大白鲨抗争才能生存。从康复的角度来看，这项运动的重点是通过拳击练习来提高关节的灵活性，以及屈伸肌群的力量。在游戏中，鲨鱼首先绕着玩家，然后凶猛地攻击，试图咬住玩家。在它咬人之后，它会后退到远远地绕着玩家转。只有当玩家在虚拟鲨鱼的鼻子上打了一拳时，才能防止被咬。如果用户成功击打鲨鱼，鲨鱼会被击晕几秒钟，然后游回离玩家安全的距离。

Because Virtual Reality (VR) technology (e.g., a head mounted display with a full body tracking system) typically cannot be used underwater, what impact aquatic VR would have on user interaction is mostly unknown, and potential important underwater applications such as pool-based physical rehabilitation remain unrealized. There has been only minimal research on aquatic VR in general, and none of that work has investigated its effects on people with disabilities. Prior research has demonstrated that VR-enhanced rehabilitation can offer many benefits, such as increased motivation through immersive games and the ability to practice in a safe environment, but VR has yet to be applied in practice to aquatic rehabilitation. In this exploratory research the PI will seek to determine effective system and interaction approaches for aquatic VR that maintain rehabilitation motivation and maximize exercise performance by disabled persons, specifically for individuals with Multiple Sclerosis (MS) who commonly have proprioceptive and balance deficits. The PI's preliminary work suggests that a video see-though display, body tracking via inertial measurement units, and head positioning via optical tracking will enable an effective aquatic VR system. The PI's hypothesis is that aquatic VR will enable members of the target population to perform exercises significantly better than on land. If this hypothesis is found to be supported, the project will represent a critical step towards the grand challenge of universal usability of VR, and will in particular afford a deeper understanding of the effectiveness of VR as a medium for rehabilitation. To test his hypothesis, the research will include two thrusts. One of these will seek to determine viable system approaches for enabling aquatic VR. In preliminary work, the PI devised a prototype system consisting of a novel combination of off-the-shelf components. A waterproof smart phone was attached to a dive mask, to enable a 3DOF tracked stereoscopic view of the virtual underwater environment. A second waterproof smart phone was attached to the user's chest, allowing for 3DOF body orientation tracking, punch detection and haptic feedback. The virtual sounds of the game were delivered through a pair of waterproof headphones, which also allowed real sounds to be heard underwater. The other thrust in this project will determine through a series of empirical studies how aquatic VR affects human performance of rehabilitation exercises, Considering the known advantages of aquatic rehabilitation over land-based, the working hypothesis here is that aquatic VR will enable persons with disabilities to experience significantly less fatigue, maintain balance better, and exercise longer with increased resistance than land-based virtual rehabilitation, and that it may also improve motivation compared to traditional aquatic rehabilitation. In preliminary work, the PI developed Shark Punch, a prototype aquatic VR game in which players must fight for their lives in a real underwater environment against a virtual Great White shark. From a rehabilitation perspective, this game focuses on improving joint mobility, and flexor and extensor muscle strength, through punching exercises. In the game, the shark first circles the player and then ferociously attacks, trying to bite the player. After it bites, it retreats back to circling the player from a distance. A bite can only be prevented if the player lands a real punch on the virtual shark's nose. If the user successfully punches the shark, the shark is stunned for a few seconds and then swims back to a safe distance from the player.