Accessibility of Virtual Reality for Persons with Disabilities
Immersive virtual reality – i.e., completely blocking out the real world through a virtual reality display – is not currently universally usable or accessible to many persons with disabilities, such as persons with balance impairments.
Virtual reality (VR) has traditionally been too expensive for the consumer market, which has constrained its applicability to high cost applications, such as soldier training, surgical training, and psychological therapy. However, with the decreasing costs of head mounted displays (HMD) and real-time tracking hardware, VR may soon be in homes all over the world. For example, HMDs such as the Oculus Rift (https://www.oculus.com/) for VR and Microsoft’s upcoming Hololens (https://www.microsoft.com/microsoft-hololens/) for augmented reality (AR) will change the way that users play games and experience the surrounding real world, respectively. Moreover, VR and AR can now be effectively enabled through smartphones at an even lower cost with the simple addition of a head mounted case, such as MergeVR’s headset (http://www.mergevr.com/). That is, everyone with a smartphone has virtual environment (VE) devices in their pockets right now. Thus, VR will be available to consumers who may have disabilities. However, there is minimal research that highlights the special needs of these diverse populations with respect to immersive VR. Thus, there is a significant amount of research that must be conducted to make VR accessible to persons with disabilities. This entry reviews the recent efforts of the San Antonio Virtual Environments (SAVE) lab to better understand how persons with disabilities are affected by VR accessibility.
Most of the information that is known about the accessibility of VR for persons with disabilities comes from research on virtual rehabilitation. VR has been shown to have significant benefits to rehabilitation. A VE is not subject to the dangers and limitations of the real world (Boian et al. 2002; Burdea 2003; Wood et al. 2003; Merians et al. 2006), which expands the types of exercises that patients can practice, while still having fun in the case of VR games. In general, research suggests that VR and VR games have measurable benefits for rehabilitation effectiveness (Sveistrup 2004; Eng et al. 2007; Ma et al. 2007; Crosbie et al. 2008; Adamovich et al. 2009) and motivation (Betker et al. 2007; Verdonck and Ryan 2008).
Visual Feedback: Visual feedback is any kind of feedback for rehabilitation delivered to the patient through the visual modality. This includes mirrors, computer displays, and VR. Visual feedback has been shown to be effective in rehabilitation (Sütbeyaz et al. 2007; Čakrt et al. 2010; Thikey et al. 2011).
Gait Rehabilitation: Gait (i.e., walking patterns) rehabilitation is the main type of rehabilitation that requires navigation in a VE. Most systems used a head mounted display (HMD) or a large LCD screen. Results with VR systems in gait rehabilitation were positive (Fung et al. 2006; Tierney et al. 2007; Bardack et al. 2010).
Design Guidelines for VR Rehabilitation Games: There has been much research on deriving design guidelines for VR rehabilitation games based on results of empirical studies (Flynn et al. 2008). Alankus et al.’s guidelines include: simple games should support multiple methods of user input, calibrate through example motions, ensure that users’ motions cover their full range, detect compensatory motion, and let therapists determine difficulty (Alankus et al. 2010). There have been many other guidelines derived (Goude et al. 2007; Broeren et al. 2008; Burke et al. 2009a, b) and there is a need for more focused game design research and development for specific populations (Flores et al. 2008).
SAVE Lab’s Research in Immersive VR Accessibility
Making Balance Games More Accessible
Specifically, users control orientation through rotating the cane and leaning in each direction to control direction of movement. To meet the rehabilitation goal of reducing dependency on the cane, putting weight on the cane will disrupt movement (e.g., make a character run slower; make a car more difficult to turn).
Results of a user study suggest that the Game Cane is easy to use and serves as sufficient motivation to depend less on the cane during game play. In the future, we plan to study long term effects of balance improvement using Game Cane.
One of the major potential threats to accessibility is latency. Latency is the time it takes between a user moving and the movement being shown on a virtual reality display (e.g., a head mounted display, a 3D projector). All VR systems have latency in them and classically latency has been the enemy of VR, often significantly hindering user performance.
Accessibility for Children with Autism
Raising Awareness About Persons with Disabilities
The SAVE lab is trying to push the boundaries of VR to make it accessible for all users, including persons with disabilities. We have conducted fundamental research towards understanding how persons with disabilities interact with VR and have identified techniques to make VR more accessible. However, there is still a significant amount of research to be done before immersive VR can truly be accessible to everyone.
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