Encyclopedia of Computer Graphics and Games

Living Edition
| Editors: Newton Lee

Accessibility of Virtual Reality for Persons with Disabilities

  • John QuarlesEmail author
Living reference work entry
DOI: https://doi.org/10.1007/978-3-319-08234-9_68-1



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

Many existing balance based games are not accessible for many persons with balance impairments. To address this issue Cantu et al. developed a novel interface – Game Cane (Fig. 1) (Cantu et al. 2014). Game Cane enables the user to control games and play balance based games using the natural affordances of a cane. The Game Cane project has two goals: (1) make balance games more accessible and (2) help users with balance impairments to improve their balance.
Fig. 1

Game Cane. The user leans forward to move the character forward and rotate the cane to steer. If more weight is put on the cane (as measured by the force sensitive resistor), it will disrupt the movement of the character in the game

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.

However, we hypothesized that in some cases, extra latency can potentially be used for the user’s benefit in areas such as stroke rehabilitation. For example, in a recent study (Samaraweera et al. 2015), we intentionally applied an extra 200 ms of latency to the user’s virtual body, but only half of the body, which made the unaffected half of the user’s body try to compensate for the latent half. In this study, participants were asked to walk towards a virtual mirror in which they could see their avatar (Fig. 2). Interestingly, participants did not perceive the latency effect. Based on her promising results, we are now conducting a study on the benefits of this one-sided latency for stroke patients who commonly have increased weakness on one side. The ultimate goal is to apply her technique to help rehabilitate asymmetric walking patterns in these patients.
Fig. 2

Benefits of Latency: a look into a virtual mirror where the avatar has 200 ms latency applied to one side of the body

Accessibility for Children with Autism

Motivation may be a factor in the accessibility of 3D User Interfaces for children with Autism. It has been shown that many children with Autism have very specific and individualized interests, many of which may be uncommon. To more effectively motivate children with Autism to practice hand-eye coordination tasks, we created a virtual soccer game, Imagination Soccer (Fig. 3), where the user played the role of a goalie and he/she could customize a virtual human kicker (Mei et al. 2015). We compared customizable versus noncustomizable virtual humans. As expected, we found that the participants preferred the customizable virtual humans. Surprisingly, the users also exhibited significantly improved task performance with the customizable virtual humans. This suggests that customization is a plausible way to make interfaces more accessible for children with Autism.
Fig. 3

Imagination Soccer – a game for training hand-eye coordination for children with Autism

Raising Awareness About Persons with Disabilities

Virtual reality still has a long way to go before it can be considered accessible for persons with disabilities. To educate future VR designers and engineers about accessibility in VR, it is important to raise awareness about the needs of persons with disabilities. One of the ways that the SAVE lab has been raising awareness is through our Virtual Reality Walk MS (SAVELab 2015b) (Fig. 4) and our Virtual Reality Walk for Autism (SAVELab 2015a). Using Unity3D (unity3d.com) and Exitgames Photon (exitgames.com) for networking, the VR walks mimic the real fundraising walks that occur annually, effectively involving potential participants who may not be able to attend the real walk. The VR walks are run concurrently with the real walks. Users can choose an avatar and virtually walk around a virtual AT&T center. Users who are remote are also able to communicate with people at the real walk since the software runs on mobile phones. However, there are still many research problems to be solved to make communication more natural and the interface more transparent. This is an area where new advances in augmented reality technology may help to address these issues.
Fig. 4

Virtual Reality Walk MS – a mobile, multiplayer virtual environment for raising awareness about multiple sclerosis


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.


  1. Adamovich, S., Fluet, G., Tunik, E., Merians, A.: Sensorimotor training in virtual reality: a review. NeuroRehabilitation 25(1), 29–44 (2009)Google Scholar
  2. Alankus, G., Lazar, A., May, M., Kelleher, C.: Towards customizable games for stroke rehabilitation. CHI, ACM (2010), Atlanta, GAGoogle Scholar
  3. Bardack, A., Bhandari, P., Doggett, J., Epstein, M., Gagliolo, N., Graff, S., Li, E., Petro, E., Sailey, M., Salaets, N.: EMG biofeedback videogame system for the gait rehabilitation of hemiparetic individuals. Thesis, in the Digital Repository at the University of Maryland, (2010)Google Scholar
  4. Betker, A., Desai, A., Nett, C., Kapadia, N., Szturm, T.: Game-based exercises for dynamic short-sitting balance rehabilitation of people with chronic spinal cord and traumatic brain injuries. Phys. Ther. 87(10), 1389 (2007)CrossRefGoogle Scholar
  5. Boian, R., Sharma, A., Han, C., Merians, A., Burdea, G., Adamovich, S., Recce, M., Tremaine, M., Poizner, H.: Virtual reality-based post-stroke hand rehabilitation. Medicine meets virtual reality 02/10: digital upgrades, applying Moore’s law to health: 64 (2002). Los Angeles, CAGoogle Scholar
  6. Broeren, J., Bjorkdahl, A., Claesson, L., Goude, D., Lundgren-Nilsson, A., Samuelsson, H., Blomstrand, C., Sunnerhagen, K., Rydmark, M.: Virtual rehabilitation after stroke. Stud. Health Technol. Inform. 136, 77–82 (2008)Google Scholar
  7. Burdea, G.: Virtual rehabilitation-benefits and challenges. Methods Inf. Med. 42(5), 519–523 (2003)Google Scholar
  8. Burke, J., McNeill, M., Charles, D., Morrow, P., Crosbie, J., McDonough, S.: Optimising engagement for stroke rehabilitation using serious games. Vis. Comput. 25(12), 1085–1099 (2009a)CrossRefGoogle Scholar
  9. Burke, J., McNeill, M., Charles, D., Morrow, P., Crosbie, J., McDonough, S.: Serious Games for Upper Limb Rehabilitation Following Stroke. IEEE Computer Society (2009)Google Scholar
  10. Čakrt, O., Chovanec, M., Funda, T., Kalitová, P., Betka, J., Zvěřina, E., Kolář, P., Jeřábek, J.: Exercise with visual feedback improves postural stability after vestibular schwannoma surgery. Eur. Arch. Otorhinolaryngol. 267(9), 1355–1360 (2010)CrossRefGoogle Scholar
  11. Cantu, M., Espinoza, E., Guo, R., Quarles, J.: Game cane: an assistive 3DUI for rehabilitation games. In: 3D User Interfaces (3DUI), 2014 I.E. Symposium on, IEEE (2014). Minneapolis, MNGoogle Scholar
  12. Crosbie, J., Lennon, S., McGoldrick, M., McNeill, M., Burke, J., McDonough, S.: Virtual reality in the rehabilitation of the upper limb after hemiplegic stroke: a randomised pilot study. In: Proceedings of the 7th ICDVRAT with ArtAbilitation, pp. 229–235. Maia (2008)Google Scholar
  13. Eng, K., Siekierka, E., Pyk, P., Chevrier, E., Hauser, Y., Cameirao, M., Holper, L., Hägni, K., Zimmerli, L., Duff, A.: Interactive visuo-motor therapy system for stroke rehabilitation. Med. Biol. Eng. Comput. 45(9), 901–907 (2007)CrossRefGoogle Scholar
  14. Flores, E., Tobon, G., Cavallaro, E., Cavallaro, F., Perry, J., Keller, T.: Improving Patient Motivation in Game Development for Motor Deficit Rehabilitation. ACM, New York (2008)CrossRefGoogle Scholar
  15. Flynn, S., Lange, B., Yeh, S., Rizzo, A.: Virtual reality rehabilitation–what do users with disabilities want? in the Proceedings of ICDVRAT 2008, Maia & Porto, Portugal (2008)Google Scholar
  16. Fung, J., Richards, C., Malouin, F., McFadyen, B., Lamontagne, A.: A treadmill and motion coupled virtual reality system for gait training post-stroke. Cyberpsychol. Behav. 9(2), 157–162 (2006)CrossRefGoogle Scholar
  17. Goude, D., Björk, S., Rydmark, M.: Game design in virtual reality systems for stroke rehabilitation. Stud. Health Technol. Inform. 125, 146 (2007)Google Scholar
  18. Ma, M., McNeill, M., Charles, D., McDonough, S., Crosbie, J., Oliver, L., McGoldrick, C.: Adaptive virtual reality games for rehabilitation of motor disorders. Universal Access in Human-Computer Interaction. Ambient Interaction, pp. 681–690. (2007). Bejing, ChinaGoogle Scholar
  19. Mei, C., Mason, L., Quarles, J.: How 3D Virtual Humans Built by Adolescents with ASD Affect Their 3D Interactions. ASSETS, Lisbon (2015)Google Scholar
  20. Merians, A., Poizner, H., Boian, R., Burdea, G., Adamovich, S.: Sensorimotor training in a virtual reality environment: does it improve functional recovery poststroke? Neurorehabil. Neural Repair 20(2), 252 (2006)CrossRefGoogle Scholar
  21. Samaraweera, G., Perdomo, A., Quarles, J.: Applying latency to half of a self-avatar’s body to change real walking patterns. In: Virtual Reality (VR), 2015 IEEE.IEEE (2015). Arles, FranceGoogle Scholar
  22. SAVELab: VR Walk MS: San Antonio. From https://play.google.com/store/apps/details?id=com.SAVELab.MSWalk&hl=en (2015b)
  23. Sütbeyaz, S., Yavuzer, G., Sezer, N., Koseoglu, B.: Mirror therapy enhances lower-extremity motor recovery and motor functioning after stroke: a randomized controlled trial. Arch. Phys. Med. Rehabil. 88(5), 555–559 (2007)CrossRefGoogle Scholar
  24. Sveistrup, H.: Motor rehabilitation using virtual reality. J. NeuroEng. Rehabil. 1(1), 10 (2004)CrossRefGoogle Scholar
  25. Thikey, H., van Wjick, F., Grealy, M., Rowe, P.: A need for meaningful visual feedback of lower extremity function after stroke. IEEE (2011). Dublin, IrelandGoogle Scholar
  26. Tierney, N., Crouch, J., Garcia, H., Walker, M., Van Lunen, B., DeLeo, G., Maihafer, G., Ringleb, S.: Virtual reality in gait rehabilitation. MODSIM World (2007). Richmond, VAGoogle Scholar
  27. Verdonck, M., Ryan, S.: Mainstream technology as an occupational therapy tool: technophobe or technogeek? Br. J. Occup. Ther. 71(6), 253–256 (2008)CrossRefGoogle Scholar
  28. Wood, S., Murillo, N., Bach-y-Rita, P., Leder, R., Marks, J., Page, S.: Motivating, game-based stroke rehabilitation: a brief report. Top. Stroke Rehabil. 10(2), 134–140 (2003)CrossRefGoogle Scholar

Copyright information

© Springer International Publishing Switzerland 2015

Authors and Affiliations

  1. 1.Department of Computer ScienceUniversity of Texas at San AntonioSan AntonioUSA