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Assistive Technology – The Bridge Between Computers and Disabled Users

By Ben Tomsky , SAP Labs, SAP User Experience – Updated: January 20, 2004

Throughout the software development community, a tremendous amount of effort is going into the process of making Websites and software applications "Section 508 compliant." This emphasis on Section 508 and other accessibility standards is reasonable but, unfortunately, other aspects of creating accessible software solutions receive little attention. In fact, Section 508 and similar regulations represent only half the story of how disabled individuals access electronic media-assistive technology (AT) forms the crucial link between the disabled user and the computer.

 

What is Assistive Technology?

Section 508 provides an explicit answer to this question: "Assistive technology is defined as any item, piece of equipment, or system, whether acquired commercially, modified, or customized, that is commonly used to increase, maintain, or improve functional capabilities of individuals with disabilities." Yet, this definition is very broad, potentially including anything from wheelchairs to hearing aids. In the context of Section 508, the term typically refers to tools used by disabled individuals to increase or improve the functionality of information technology.

Assistive technology can be either software- or hardware-based. Hardware solutions can span a broad range of devices, from low-tech items such as mouth sticks or paper stabilizers, to high-tech products such as refreshable Braille displays or eye gaze communication systems. Software solutions can include built-in features such as the accessibility options in Microsoft Windows or stand-alone programs such as speech recognizers and screen readers. The most appropriate type of AT for a disabled individual depends on the nature of the disability.

The following outline of assistive technology, grouped by the nature of a user's disability, represents a sample of the many types of assistive technology that are available.

 

Assistive Technology for Visual Impairments

Visually impaired individuals include those who are completely blind as well as those who have low vision, those who are colorblind, and those with impaired optical muscle control. Each of these conditions calls for a slightly different assistive technology.

Blind Users

Blind users face the greatest challenge when interacting with graphical user interfaces. Typically, they use software applications known as screen readers that turn the text, events, and elements in applications and Websites to synthesized speech. For example, when a user opens a new window in Microsoft Internet Explorer, a screen reader might say "new browser window."

Special key combinations are used to move around screens in order to direct the screen reader what to read. By listening to this speech, blind users are able to understand a screen's content.

A refreshable Braille display may be used as a supplement or alternative to a screen reader. These devices convert screen text to Braille and display the Braille on a number of cells comprised of independently controlled pins. When editing and reviewing text, refreshable Braille displays can be much better to work with because a blind user can easily reread characters on the same line and check spelling. Screen readers are capable of reading words character by character, but the process of moving backwards in text to review and then moving forwards can be cumbersome. Despite their potential advantages, refreshable Braille displays are less common because of their high cost and because the majority of blind individuals in the US do not read Braille. See www.pulsedata.com/products/notetakers/Notetakers_index.asp for an example of a refreshable Braille display.

A Braille embosser provides a mechanism for blind users to print a hard copy of text. After text has been converted to Braille through a software application, embossers emboss on thick paper the individual dots that constitute Braille characters. See www.brailler.com/tom.htm for an example.

Users with Low Vision

Users with low vision utilize screen magnifiers, software which enlarges information on the screen by a user-defined factor (e.g., 2x magnification, 3x magnification, etc.). These applications can magnify parts of the screen, the full screen, or provide a magnifying glass view of an area around the cursor or pointer. Because of this enlarging, users with low vision can read onscreen text and interact with screen elements. See www.zoomtext.com/products/zx.htm for an example.

 

Assistive Technology for Mobility Impairments

The term "mobility impairment" refers to any condition that limits one's ability to navigate his or her environment. Some conditions that result in mobility impairments are: brain damage, muscular dystrophy, arthritis, paralysis, and amputation. To accommodate the variety of potential mobility impairments, many different types of AT are available.

Alternative pointing devices allow mobility-impaired individuals to control the mouse pointer via a mechanism other than the mouse. These are typically used when someone lacks the dexterity to manipulate a standard mouse.

Perhaps the most simple of these devices, software exists that converts the keyboard's arrow keys into directional movements for the pointer. Other keys are used to signal a left and right mouse click. For users with very limited motion with their hands, a standard computer joystick may be used in combination with special software that converts the joystick's motion to directional control of the pointer.

Technologically complex solutions exist for individuals with severe impairments, entirely unable to manipulate the mouse and/or use a standard keyboard. For example, the HeadMouse wireless pointing device (see orin.com/access/headmouse/index.htm) converts the movements of a user's head into corresponding movements of the mouse pointer by optically tracking the motion of a single point on the user's head. A standard keyboard may be completely replaced by using this system in conjunction with software that produces an on-screen keyboard.

In addition to this combination of two technologies, other alternatives to conventional keyboards exist. For users with somewhat compromised manual dexterity, keyboards with extra-large keys may be used. See www.fentek-ind.com/bigkey.htm for examples.

As yet another option, mobility impaired individuals may utilize speech recognition applications. This software can be used to both control applications via speech commands and as a means to dictate text, with the speech converted to text in real-time. See www.lhsl.com/naturallyspeaking for an example.

 

Assistive Technology for Hearing Impairments

Hearing impairments affect individuals over a range of severity, including the inability to hear certain types of sounds, the inability to hear any sound, and difficulty distinguishing words. Because computers rarely convey information with sound alone, hearing impaired individuals have encountered few accessibility problems-at least until the arrival of multimedia. Yet, some solutions are emerging.

Computer prompts such as spoken messages and beeps can be misunderstood or go unnoticed by hearing impaired individuals. This problem is solved through the use of tools that produce a visual warning when the system plays a sound and/or tools that display captions in place of a spoken message. Microsoft Windows includes SoundSentry and ShowSounds as part of its accessibility options to do just that; see www.microsoft.com/enable/products/chartwindows.htm for descriptions of these and other built-in Windows accessibility features.

 

Assistive Technology for Cognitive Impairments

Given the disparate nature of the many learning and cognitive impairments, a variety of assistive technologies is employed, often overlapping with those used by other groups of disabled individuals. For example, cerebral palsy is a cognitive condition that potentially causes any combination of the following: visual impairments, mobility impairments, and hearing impairments. Thus, individuals affected by cerebral palsy may utilize any number of assistive technologies that are also used by individuals with other impairments.

However, some assistive technologies are designed specifically for cognitive impairments. Word prediction software is used by dyslexic individuals and those who type very slowly. This software predicts the completion of the word currently being typed and can predict the next word based on word context and frequency. See www.madentec.com/products/comaccess/telepathic/telepathic.html for an example.

 

Conclusion

As evidenced by the above descriptions, assistive technology services a variety of disabilities in numerous ways. Yet, designers and developers need not concern themselves with the details of each assistive technology. The established guidelines and legislations, such as Section 508 and the Web Accessibility Initiative, provide explicit checkpoints that facilitate the production of Websites that are compatible with multiple types of assistive technology. However, universal guidelines do not provide coding techniques for languages other than HTML. Therefore, when developing applications, an expert in assistive technology should be consulted in order to avoid creating barriers for assistive technology users.

For more information on accessibility guidelines, see the Design Guild article The Web Content Accessibility Guidelines, a Commented Overview.

For more information on Section 508, see the Design Guild article 508 - Any More Questions?.

 

Overview of Links Presented in this Article

The following external links are offered in this article:

 

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