A Survey of Computer Interfaces for People with Disabilities
With the evolution of technology, this is a critical time for people with disabilities who have much to gain by accessing emerging technologies–and much to lose if access is denied.
(Atkinson et al, 2003, p. 177)
Computing interfaces that provide access to technology for people with disabilities is necessary more than ever. It is important that accessibility to the Internet, electronic educational sources, and computing power is available at both the home and workplace. The evolution of computing technology has provided for lower cost higher performing machines that can handle the real-time processing needed to provide better accessibility features.
The current unemployment rates for people without disabilities is 9.4% compared to 14.8% for those with disabilities (Monthly Labor Review, 2011). Although it cannot be directly attributed to accessibility, society must strive to provide everyone with a fair chance to succeed. Awareness of current available options and research will help provide a better idea to maximize accessibility for those with disabilities.
This paper was written with the intention to educate people of the current state of accessibility options available as well as the research currently taking place. Because of the vast amount of technologies and devices available only a select number of them will be discussed. The hope is to cover technologies that directly affect those with hearing disabilities, paralysis, blindness, and other visual impairments, cognitive, and learning disabilities, and amputation.
Problems in Computing for People with Disabilities
As a preface to the technologies that are available or are currently in research this section provides an overview of the limitations and barriers that accessibility technologies must help overcome. Although every technology will most likely only address one type of barrier it is important to fully understand what current problems these technologies are solving. “These barriers can be grouped into three functional categories: Barriers to providing computer input, interpreting output, and reading supporting documentation” (Burgstahler, 2001, p. 1).
Input barriers exist when a user is functionally unable to use directly conventional devices such as a keyboard or mouse. Such problems can be found in people with full or partial paralysis, blindness, amputation, and cognitive, or learning disabilities. Modern advances in technology have created hardware and software solutions to help overcome these barriers. Devices designed to replace the keyboard and mouse and software that creates a simple or bigger version of an interface are available solutions. Later in this paper an eye tracking system will be discussed that allows the user to use their eyes as a mouse on screen.
Output and the ability to read supporting documentation barriers exist when a user is unable acquire the visually stimuli that a computer system interface offers. Generally in this case the user cannot hear, has low vision, or blindness. Solutions to this problem do exist in both hardware and software forms. Special output devices called Braille displays, speech synthesizers, visual sounds, color contrast settings, and on-screen magnifiers are available to provide an alternative to the tradition monitor and speaker.
As technology continues to evolve so will the solutions to the barriers in universal accessibility. Computers are becoming an increasingly larger portion of society providing a better quality of life and education to everyone. The next section provides a closer look at modern human-computer interfaces that currently or will change the lives of those using them.
Operating System Accessibility Options
Advancements in software and hardware research greatly have increased the ability to include tools built directly into operating systems such as Microsoft Windows (www.microsoft.com/enable) and Mac OS X (www.apple.com/accessibility). Both of these operating systems have made an effort to include basic accessibility features that can be enabled from within the operating system. These features include image magnification, text-to-talk, on-screen keyboards, visual sounds, sticky keys, and Internet accessibility. (Atkinson et al, 2003, p. 177) Mac OS X has also included the ability to simplify the operating systems interface for those with cognitive and learning disabilities as well as the support for Braille displays that will be discussed later in this paper.
Both of these operating systems feature a variation of speech recognition software. Speech recognition software allows the user to say commands rather than use a mouse or keyboard. This powerful feature was at one time very hard to use and unreliable. Since then processing power has increased the technology has become far more accurate and easy to use. As a test speech recognition software was enabled using a Windows 7 machine. The speech recognition software performed exceptionally well for basic functionality commands which were printed during the setup. As an attempt to test the speech-to-text feature, the author used it for 90% of the this paragraph. Problems in translation did occur however it could be attributed to the lack of time to set up and train the software for the voice.
Alternative Keyboard Solutions
Alternative solutions to conventional keyboards provides users with different motor skill abilities to increase their accuracy and usability. Because certain situations require different features keyboard manufacturers have developed various version that increase the accessibility of individuals with disabilities. Figure 2 displays a summary of the most common types of alternative keyboard types available.
| Alternative Keyboard Types | |
| Mini Keyboards | A keyboard with miniature buttons. These keyboards are for users with fine motor skills that require a much smaller area to type. Could be used with mouth stick, pointer, or fingers |
| Expanded Keyboards | Generally consist of bigger buttons. Allows for a greater range of motion. Could be used with fist, feet, hands, or fingers. |
| Chording Keyboards | Consist of a fewer number of keys. Combinations of keys create characters. Often the most common characters are the initial keys. |
| Braille Keyboard | Keyboard with Braille characters where the normal alpha-numeric keys are. |
Figure 1, (Brodwin et al, 2004, p. 29)
Alternative Mouse Solutions
Alternative types of mice are much fewer than that of their keyboard counterpart. Whereas keyboard remain static during their use, the mouse is a dynamic device. The unpredictability of its movements have led to only a few physical adaption’s. Hands-free technology is increasingly becoming more of a topic of research. The next few sections of this paper will provide information on further in-depth hands free solutions for individuals who have severe motor skill impairments. Figure 2 provides a summary of the different types of mice available on the market that aid those with physical disabilities.
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| Alternative Mouse Types | |
| Track Ball | Uses a ball that can be pivoted with one hand while the other hand hits a lock down button. Easy for highlighting, dragging, and dropping. |
| Mouse Sticks | Uses a pressure sensitive stick that allows the user to use one finger to control the mouse. |
| Hands-Free Mouse | Head tracking unit, Eye tracking system, or Brain Computer interface. |
| TrackPad | Found it most laptop computers. Area of movement is low and allows for clicking without button interaction. |
Figure 2, (Brodwin et al, 2004, p. 30)
Braille Displays and Text-to-Speech
Braille displays provide an alternative solution for those who suffer from blindness or have extremely low vision. Using a grid of holes with pins these machines incorporate motors that can create the Braille alphabet and numeric system. Braille displays are much like a Braille book however they display information as it is requested from the user. These devices can be used in popular operating systems and even with phones for texting via Bluetooth. Most Braille displays are expensive ranging from $1000 to $5000 devices, depending on the number of cells on the unit. Venders selling these types of displays can be easily found by doing a web search or checking out an online auction house.
Text-to-speech is an alternative to Braille displays and comes standard on most operating systems. This software uses a speech synthesizer to vocalize on-screen text and alerts so a user with a visual disability can interact with the system. Text-to-speech software works well in providing auditory feedback about the status of a system and reading contents of web pages. There are drawbacks to the system as it cannot access content embedded in graphical images unless the content is in an accessible format (Burgstahler et al, 2007, p. 94). Because this software comes standard on most operating systems the only cost is the operating system itself. Commercial versions available that have different features and voices.
Eye Tracking Systems
The use of eye tracking systems benefits those individuals who suffer from paralysis or other diseases or situations that decrease or eliminate movement of the body below the eyes. These tracking systems generally do not require substantial processing power to implement and are cost-effective solutions. Many of these eye tracking interfaces have been designed through universities however there are commercial vendors that specialize in eye tracking and its various benefits including sales analysis and car safety features.
Using a camera and computer software the system can be set up and used as a human-computer interface that allows a person to control an on screen mouse with eye movements. Research into the algorithms and technology to create affordable eye tracking solutions for people with disabilities has been conducted by a team from the National Central University in Taiwan. This research used a 533mhz Pentium II pc running Windows 2000 and a Sony CCD camera (Su et al, 2006, p. 319). In this study the CCD camera was used to detect a human face using a skin color filter method. Further detection of the eye was processed in real-time from the computer using advanced programming techniques. The team ran tests successfully that resulted in their subjects to navigate to areas on the screen. Since this study eye tracking software can be found on the Internet freely available and in open source format and usable with many web cams.
Current and future research expand upon the approach of eye tracking as an interface for people with disabilities, to a powerful research tool for various conditions such as Dyslexia and Attention Deficit Disorder. This research uses the specifically designed programs and an eye tracking interface to trace and record where the eye focuses on various words or images and for what length of time. The idea is that where a person looks is thought to be “on top of the stack” for cognitive processes (Poole & Ball, 2005, p. 3). Using this information of where attention is focused allows researchers to further gain an understanding of the human mind.
Future Research in Brain-Computer Technology
Brain-Computer Interface research is still in its early stages, however, is showing promising results for the future. Earlier research used large mainframe computers and non -invasive electrodes to read and process the information. These studies still relied on physical movement of the eye to generate electroencephalogram (EEG) that was computed in with minor lag to show results (Mcfarland & Wolpaw, 2011, p.60). Although there was still muscular involvement used this BCI was monumental.
Since then research has been conducted using real-time processing on modern computers. Development of home use systems has provided functionality by using an electrode cap, a laptop computer and a screen in front of the individual (Mcfarland & Wolpaw, 2011, p. 60). This functionality includes the ability to use letter selection to type on screen words onto a computer. In the May 2011, Communications of the ACM reported that a 49-year-old man who suffered from loss of motor functions because of advanced amyotrophic lateral sclerosis (ALS) has been using this device for three years and prefers it over the eye tracking system he had before.
The practical uses for extreme motor function loss are apparent and useful today however, BCI deserves much more research to take this technology to the next level. Other studies include the use of BCI to control wheelchairs, or prosthetic limbs. With this technology still in an early age, the promise of achievement is evident.
Future Research in Facial Mouse Technology
Chinese students at National Central University are developing a way of controlling an onscreen mouse using facial muscle activity patterns. The idea is to use electromyography, and a minimal amount of electrodes to translate muscular movement to onscreen movement. Much like the brain-controlled interface that was discussed in the previous section, noise is picked up by the electrodes and fed to a computer. The difference is the facial mouse uses EMG that is mostly considered noise to the BCI.
The students have developed a working model of which they tested on six human subjects. Each subject was given 12 commands to complete during the test. On average the test subjects scored above 83% in accuracy. This accuracy is also coupled by with five additional trials timing the seconds to complete 12 commands. The trial group successfully completed the commands in 35-59.2 seconds.
Summary
Computing technology continues to grow, increasing societies quality of life. Education, information, and entertainment are readily available for anyone that has access to the Internet. As the availability of computers has increased so should the accessibility options. Enabling accessibility to people with various disabilities opens new possibilities that will positively affect society.
This paper was written with the intent to inform people of the issues, solutions, and research that are affecting those people who cannot use conventional user interfaces for computing. In the near future it is hoped that the research is properly funded so it will ignite a spark of genius in those who beforehand were not given the proper tools to participate in technologies evolution. People should be given an opportunity to succeed, and this is no different with computing technology. It is societies duty to continue research that will benefit those who cannot use conventional computer access.
References
Atkinson, T., Neal, J., & Grechus, M. (2003). What Works for Me: Microsoft Windows XP Accessibility Features. Intervention in School and Clinic, 38(3), 177-80.
Brodwin, M. G., Star, T., & Cardoso, E. (2004). Computer Assistive Technology for People who Have Disabilities: Computer Adaptations and Modifications. Journal of Rehabilitation, 70(3), 28-33.
Burgstahler, S. (2001). Working together: people with learning disabilities and computer technology. Exceptional Parent, 31(6), 36-39.
Burgstahler, S. E., & Ladner, R. E. (2007). Increasing the Participation of People with Disabilities in Computing Fields. Computer, 40(5), 94-97.
Cheng-Ning, H., Chun-Han, C., & Hung-Yuan, C. (2006). Application of facial electromyography in computer mouse access for people with disabilities. Disability & Rehabilitation, 28(4), 231-237.
Mcfarland, D., & Wolpaw, J., (2011). Brain-computer Interfaces for Communication and Control. Communications of the ACM, 54(5), 60-66
People with disabilities and employment. (2011). Monthly Labor Review, 134(6), 2.
Poole, A., & Ball, L. (2005). Eye Tracking in Human-Computer Interaction and Usability Research. Current Status and Future Prospects. Human Computer Interaction Lancaster University, UK
Su, M., Wang, K., & Chen, G. (2006). An Eye Tracking System and its Application in Aids for People with Severe Disabilities. Biomedical Engineering Applications, basis & Communications, Vol. 18 No. 6, pp. 319-327
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