Assistive Computer Technology for Persons with Disabilities

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Assistive technology Summary

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Assistive Computer Technology for Persons with Disabilities

The personal computer (PC) can be the backbone of independence for millions of individuals with sensory, physical, and learning disabilities. Computersand information technology can be modified with alternative input, alternative output, and other assistive technology to empower consumers who have disabilities. Computer vendors support persons with disabilities by incorporating accessibility utilities into operating systems such as Microsoft Windows, Apple Macintosh, and UNIX. PCs equipped with assistive technology permit individuals to function independently at school, work, and home, and allow access to great quantities of information from diverse sources such as compact disks, networks, electronic mail, instant messaging, the World Wide Web, and other Internet resources. For the purposes of this discussion, the term "assistive technology" will be used to describe any hardware device or software program that permits individuals with disabilities to operate PCs and access information technology independently. Moreover, this article uses the definition of disability as outlined in the Americans with Disabilities Act in the United States, and the Disabilities Discrimination Act in the United Kingdom—any permanent condition that impairs a major life function such as seeing, hearing, walking, or speaking.

Personal Computer Platforms

Since their advent in the early 1980s, PCs have become a vital tool for business and education applications, and are now common in many homes. Personal computer platforms are a combination of hardware and software, working together in synergy. The hardware is the physical structure of the system, and software is the set of instructions that control the hardware. PC hardware consists of several fundamental components, including the central processing unit, memory units, disk drive storage, keyboard, and video monitor or screen.

For persons with disabilities, the keyboard, mouse, and monitor are of prime concern. PCs employ input devices like keyboards and mice for entering information and for controlling the system. Output devices, like monitors and printers, display processed information. Adapting PCs for use by persons with disabilities involves the modification of these standard input and output devices with assistive hardware or software. For example, adapting a computer's output systems to use speech or Braille printouts can make the computer accessible for persons with visual disabilities.

Technology for Persons with Vision Impairments

The video monitor is a standard output device for PCs. By its nature, the monitor relies on the visual sense to convey information. For persons with vision-related disabilities, the monitor can present a significant barrier, depending on the nature of the vision loss. The output of a standard computer printer is also fundamentally inaccessible for persons with vision impairments. Several assistive technologies that can help compensate for visual impairments include video magnification, screen readers, Braille displays and printers, and optical character recognition systems.

Magnification software enlarges text and graphics displayed on PC monitors. Magnification programs are widely used by persons with poor vision or who have difficulty reading. They focus a larger image on the retina, making text and graphics more visible. Most magnification programs can magnify either the whole screen, or just a select region of the screen. Some basic magnification utilities magnify just the mouse pointer or cursor. Mostcomprehensive packages allow the user to change the screen contrast and font or adjust the magnification in steps. Some programs provide speech output and magnification at the same time. Magnification software can enlarge the output from commercial applications such as word processors, databases, spreadsheets, browsers, e-mail, and other applications. Some magnification programs can also display books, magazines, and other printed materials magnified on the monitor using an external camera or scanner.

Screen readers are software programs that provide either speech or Braille output, and are commonly employed by persons who are blind or visually impaired. Screen readers require a computer sound card and speakers to provide voice output. For Braille output, a screen reader requires a Braille display. Braille displays connect to the PC and contain a row of mechanical Braille dots that pop up and down under computer control. The user employs arrow keys to scroll text for reading. Braille displays allow vision-impaired users to control the operating system and application programs.

For persons with vision impairments, the printed word can present a formidable barrier to independence. Optical character recognition (OCR) software can help overcome this barrier. OCR software requires a flatbed or handheld scanner to be connected to the host PC in order to function.

OCR systems are used to scan printed materials directly into the PC to accommodate many types of disabilities. Once scanned, the text can be read using a screen reader, magnification software, or Braille display or printer. OCR software can also help users with learning disabilities scan and format information in ways that help them process the information. In addition, the technology empowers those with motor-related disabilities to process and access information.

Technology for Persons with Motor Impairments

For persons with motor-related disabilities, the computer keyboard and mouse can present a significant barrier. There is a wide range of assistive technology available to compensate users who have motor disabilities. Several common input modifications include adapted keyboards, on-screen keyboards, alternative communication programs, and voice recognition.

Keyboard adaptations designed to assist users who have difficulty using the standard keyboard come in many different forms. Models exist that can be used with one hand, or with another part of the body. There are adapted keyboards that allow the keys to be rearranged to suit the user's needs. Some models allow the keyboard to be adjusted for the most suitable ergonomic fit. These can be adjusted to lay flat on the desk in the traditional manner or they can be used in a vertical configuration, if that best suits a user's preferences and needs.

On-screen keyboards are software programs that display a pictorial representation of a standard keyboard on the computer screen. The on-screen keyboard can be configured to scan through the keys one at a time through software. When the desired key is highlighted, a user can select the key by striking an adapted switch connected to the computer. Adapted switches come in many configurations; they can be controlled by breath, by hand, or by another part of the body. Some adapted switches can also be activated using voice commands.

Many motor disabilities can impact one's ability to speak, so alternative communications systems have been developed to assist persons with communications tasks at home, school, or in the workplace. Alternative communications systems range from picture boards to notebook computers equipped with speech synthesis systems capable of an unlimited vocabulary. Such systems can be used to communicate with friends, family members, and co-workers, and for tasks such as delivering presentations.

Voice recognition and dictation systems are powerful assistive technologies that allow persons with disabilities to control a computer and dictate documents verbally using spoken commands. Voice recognition software requires a computer with a sound card and a microphone to accept verbal input. Voice recognition software must be trained by the user to recognize the speaker's voice accurately, a process that takes about an hour. The software stores recorded voice patterns from the training process, and matches these stored templates against the incoming verbal command stream from the microphone. Voice recognition can be used for applications such as e-mail, web browsing, and word processing.

Technology for Persons with Hearing Impairments

Numerous forms of adaptive and non-assistive technologies are available to increase independence and quality of life for individuals who are deaf or hard of hearing. For persons with hearing-related disabilities, access to the spoken word can often present a significant barrier. Assistive technology to support users with hearing-related disabilities focuses on accessing the spoken word at home, in the classroom, or at the work site. Technologies to assist the hearing-impaired include such systems as TTYs, amplification systems, and applications like e-mail and instant messaging.

TTYs, or text telephones, allow people to type messages back and forth over the telephone. These devices allow individuals to send text messages using a keyboard and printer or visual display. They access the telephone system using standard connectors, and can be used for home, school, or business applications. There are also portable TTYs that can be used in a mobile environment.

Amplification systems increase the volume and clarity of the spoken word, making it more accessible for persons with limited hearing ability. These devices range from hearing aids that fit inside the ear to assistive listening devices that can be carried in a pocket or purse and used for large gatherings.

Users can also adjust the speaker volume on most computer platforms to increase access for persons who are deaf or hard of hearing. If the speaker volume is adjusted to zero, this causes the visual display to flash and alert the user to the presence of audio output.

Non-assistive computer programs like electronic mail and instant messaging empower individuals with hearing-related impairments to communicate over the Internet. The widespread availability of electronic mail contributes greatly to the independence of persons with hearing impairments. Instant messaging allows for expanded communication in much the same manner as electronic mail does, with an immediacy similar to that of a telephone conversation, and its wide availability to all computer users, regardless of disability, makes it attractive as a means of communication.

Noted scientist Stephen Hawking, author of A Brief History of Time, uses a computer-enabled synthesizer to replace his voice, which he lost due to illness in 1985.

Technology for Persons with Learning Disabilities

The term "learning disabilities" covers many impairments that impact the ability to process information. Technologies to assist persons with learning disabilities include speech systems that read printed material aloud, digital assistants to maintain schedules and lists of tasks, software to correct spelling, and task management software to guide users through the successful completion of projects. Many of these are standard productivity software programs used in business and education.

The Internet

The Internet is a vast network of computers that spans the globe. This important network allows persons with disabilities to share and exchange information in an accessible form. The Internet supports applications like e-mail, instant messaging, and the World Wide Web. PCs connected to the Internet, or a private Intranet, can be adapted with a wide variety oftechnologies to allow access to applications such as e-mail, web browsers, and online databases. The Internet and Intranets empower persons with disabilities to access information using speech, Braille, magnification, or some other form of assistive technology. The Internet increases independence for people with mobility issues to interact, work, and socialize. Assistive software can be loaded onto a network to allow that software to be shared by all users belonging to the network.

Assistive Technology and Computer Operating Systems

Accessibility utilities are being integrated into computer operating systems such as Windows, Macintosh, and UNIX. While these accessibility utilities differ from one platform to another, most operating systems include utilities to magnify text and graphics, convert text into synthesized speech, and help users control the keyboard and mouse functions. Operating systems are growing more compatible with assistive technology in general, and this is evidenced by Microsoft's Active Accessibility, which helps assistive technologies work together with the operating system and application programs.

Future Technology

Legislation such as the Americans with Disabilities Act in the United States and the Disabilities Discrimination Act in the United Kingdom is fostering the development of assistive technology for persons with disabilities. Section 508 of the Rehabilitation Act in the United States is helping to make the World Wide Web more accessible as well. The development of computer platforms of increasing speed and power also contributes to the ongoing evolution of assistive technology. As computers get more powerful, assistive technology also increases in capacity and potential, driven by the advancement of microprocessor-based technology. The increasing miniaturization of powerful computer components will lead to assistive technologies that are more portable, lightweight, and cost effective, allowing for increased independence and improving the overall quality of life for persons with disabilities.

Joseph J. Lazzaro