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Within the field of human-computer interaction, game accessibility refers to the accessibility of video games. Game accessibility is considered a subfield of computer accessibility, which studies how software and computers can be made accessible to users with various types of impairments. With an increasing number of people are interested in playing video games and with video games increasingly being used for other purposes than entertainment, such as education, rehabilitation or health, game accessibility has become an emerging field of research, especially as players with disabilities could benefit from the opportunities video games offer the most. A recent study estimates that 2% of the U.S. population is unable to play a game at all because of an impairment and 9% can play games but suffers from a reduced gaming experience. A study conducted by casual games studio PopCap games found that an estimated one in five casual video gamers have a physical, mental or developmental disability. As games are increasingly used as education tools, there may be a legal obligation to make them accessible, as Section 508 of the Rehabilitation Act mandates that schools and universities that rely on federal funding must make their electronic and information technologies accessible. As of 2015, the FCC requires in game communication between players on consoles to be accessible to players with sensory disabilities 
Barriers to Access
Video game Accessibility problems can be a categorized into three different categories  that correlate to a specific type of impairment:
- Not being able to receive feedback from the game due to a sensory impairment. Examples include: not being able to hear dialogue between game characters or audio cues, such as an explosion, because of an hearing impairment or unable to see or distinguish visual feedback, such as different colored gems in a puzzle game due to a visual impairment such as colorblindness.
- Not being able to provide input using a conventional input device due to a motor impairment; for example, users who rely upon using switch controller or eye trackers to interact with games may find it very difficult or impossible to play games that require large amounts of input.
- Not being able to understand how to play the game or what input to provide due to a cognitive impairment. People with learning disabilities, may have low literacy or a combination of Complex Needs, for instance an individual might also have Ataxia or limited coordination. For example, real time strategy games require a lot of micromanagement, which may be too difficult to understand and to perform for someone with a learning impairment.
Accessible game Categories
Over the past decade, small companies and independent game developers have developed numerous games that seek to accommodate the abilities of players with the most severe impairments and which has led to the definition of the following accessible game categories:
- Audio games are games specifically for gamers who are blind. These games can be played without visual feedback and instead use audio based techniques such as audio cues or synthetic speech. The audiogames website provides a comprehensive overview of available games.
- One-switch games are games that can be played using switch access and which accommodate the abilities of users with severe motor impairments or cognitive impairments. The oneswitch website provides an overview of available one switch games.
- Games for people with a learning disability, people with a Learning disability, may have low literacy or a combination of Complex Needs, for instance an individual might also have Ataxia or limited co-ordination. A detailed description of gaming with a learning disability.
- Universally Accessible games are games that offer multiple interfaces to support different impairments. An overview of universally accessible games can be found here.
These games are not only great examples of accessible games, but also drive innovation in game design. In recent years, game accessibility has been actively researched, for example in student projects . The unique limitations of the target group make such projects interesting, instructive and challenging for students.
Strategies for Improving Accessibility
There have been several attempts at composing a set of game accessibility guidelines similar to the Web Content Accessibility Guidelines.
Guidelines by Advocacy Organizations
The International Game Developers Association (IGDA) Special Interest Group on Game Accessibility proposed 19 accessibility guidelines in 2004, which were derived from a survey of 20 accessible games. The majority of the games surveyed include games for the visually impaired, and several support motor or hearing impaired gamers. The Norwegian Medialt organization published a set of 34 game accessibility guidelines on their website, based on the 19 IGDA game accessibility SIG guidelines as well as their own set of guidelines. 2012 has seen three major launches, Best Practices in Video Games in April 2012 by CEAPAT, Game Accessibility Guidelines in September 2012 by a group of developers, specialists and academics, and Includification, also in September 2012, by AbleGamers.
A general criticism of guidelines is that they tell a developer what to do but not why or how. An extensive literature survey  of existing accessible games identified a game interaction design model that allows for precisely eliciting how a disability impairs the ability to play a game. Based on this interaction design model three unique types of high level accessibility barriers can be identified. Based on existing accessible games, the following strategies are proposed to make games accessible:
- Hearing impairment and Visual Impairment
- Motor Impairments
- Cognitive impairment
- Reduce Stimuli: for example, limit the number of game objects, or simply the storyline.
- Reduce Time Constraints: for example, slow down the game.
- Reduce Input: for example, remove or automate inputs that needs to be provided.
To raise awareness within the game industry of the importance of making games accessible, in recent years several advocacy organizations and groups have been formed.
In 2003, the International Game Developers Association (IGDA) introduced the Game Accessibility Special Interest Group, founded by Thomas Westin. In 2006, the Bartiméus Accessibility foundation initiated the Game Accessibility project, a project which focuses on creating awareness and providing information for game developers, researchers and gamers with disabilities, led by Richard Van Tol. These two major groups work together as advocates within the game industry for increasing the accessibility of video games for gamers with disabilities.
In 2004 two disabled gamers, Mark Barlet and Stephanie Walker, founded AbleGamers.com, set out to further advance game accessibility in the AAA gaming space. Some of their efforts include: pressuring NCSoft to remove Game Guard from the game Aion and discussing with game developer Blizzard the addition of color blind friendly enhancements to the game World of Warcraft. In 2009 AbleGamers.com started 501(c)(3) nonprofit The AbleGamers Foundation to facilitate their work.
In 2010 the Accessible GameBase was launched by the charity SpecialEffect. This site aims to develop (and is developing) a welcoming, all-encompassing gaming community. This, alongside outreach projects such as accessible gaming roadshows and the development of a significant accessible gaming database, will see positive change.
Despite these, and many other initiatives, the situation is far from perfect: Many game developers are still very much unaware of game accessibility. Developers who acknowledge the importance of game accessibility and want to use it in their designs often don't know how to do so. Games developed in research-projects usually consist of small demos ("proofs of concept") which lack the quality and (re)playability of mainstream games. This is usually also the case with games that have been developed by the small companies and hobbyists. Knowledge about accessible game design that is gained in such projects often fails to get documented,. In recent years, game accessibility has become a topic of increasing interest to the academic research community.
- "Game Accessibility; A Survey". Springer. 2010-06-01. p. 6. Retrieved 2010-10-10.
- "Survey: 'Disabled Gamers' Comprise 20% of Casual Video Games Audience". Popcap studios. Retrieved 2010-03-08.
- http://www.afb.org/afbpress/pub.asp?DocID=aw131205. Missing or empty
- "Game Accessibility; A Survey". Springer. 2010-06-01. pp. 6–9. Retrieved 2010-10-10.
- "CiteUlike repository on game accessibility research papers". CiteUlike. Retrieved 2010-03-08.
- "Accessibility in Games: Motivations and Approaches". IGDA. Retrieved 2010-03-08.
- "Guidelines for developing accessible games". Medialt. Retrieved 2010-03-08.
- "Game Accessibility; A Survey". Springer. 2010-06-01. p. 10. Retrieved 2010-10-10.