Assistive Technology and Adaptive Strategies
Depending on their individual needs and preferences, people with disabilities interact with websites and applications in unique ways. Sometimes people configure standard software and hardware to meet their needs, and sometimes people use specialized software and hardware to perform certain tasks. This specialized software or hardware is commonly referred to as “assistive technology.”
Some assistive technology tools, such as word prediction and voice recognition are now becoming common tools that are also used by people without disabilities. These tools are being embedded into operating systems and mobile devices because they are able to improve usability and productivity for everyone. To help designers and developers understand how to create accessible content that works well for everyone, it is important to understand how people with disabilities use assistive technology and adaptive strategies to access digital information.
In the United States, the Individuals with Disabilities Education Act
(IDEA) defines an
assistive technology device
In simple terms, assistive technology can be anything that a person needs in order to overcome the effects of a disability. A tool or technique that might be convenient for a person without a disability, might actually be necessary for a person with a disability. For example, some people prefer to use keyboard shortcuts to complete tasks on a computer because they find it to be faster than using a mouse. However, a person whose vision prohibits them from seeing a mouse pointer will need computer systems and software that can be fully operated using only the keyboard. For this person, keyboard operation is not a preference, it is a necessity.
Examples of Assistive Technology
- Screen Reader – is software that processes content on the desktop and in web browsers and converts it to other forms such as text-to-speech and braille for output to a refreshable braille display. Screen readers typically provide other functions to support navigation for people who are blind, such as the ability to voice heading structure and to move around the content using a system of keyboard commands.
- Text-to-Speech – is a feature of screen reading software for people who are blind, but it is also a feature of applications that support reading for people with various types of learning disabilities. In these applications, text-to-speech is often paired with synchronized highlights so that people can visually track the words that are being spoken.
- Refreshable Braille Display – is a mechanical terminal that displays a line of braille characters by dynamically raising and lowering pins that form dots in a braille cell. There are also braille notetakers that have refreshable braille components and incorporate word processing software, calculators and other tools.
- Screen Magnification Software – is used primarily by people with low vision who need to enlarge content to make it easier to see. Some screen magnifiers provide text-to-speech and other functionality, such as the ability to change the foreground and background colors and the ability to change the appearance of the mouse pointer.
- Alternative Keyboards and Alternative Mice – are hardware and software used by people who need alternative input systems to interact with computers and other digital devices. Examples include keyboards with larger keys, key labels, key spacing, or custom layouts; on-screen keyboards, touchscreens, sip-and-puff switches, and single-key switches; trackballs, joysticks, touchpads, specially designed mice, and other pointing devices; voice recognition, eye tracking, and other methods for hands-free interaction.
- Eye tracking (sometimes called “eye-gaze”) – is a system that monitors eye movement to control the mouse pointer and detects blinking to initiate mouse clicks.
- Keyboard customization – includes changing the mapping of keys, assigning shortcut keys to functions, setting filters, and setting “sticky keys” to support single-handed typing.
- Mouse customization – includes changing the mapping of buttons, changing the sensitivity of the mouse towards movement, setting filters, and changing the size and appearance of the mouse pointer.
- Voice recognition (sometimes called “speech input” or “voice command”) - software that recognizes the human voice and can be used to dictate text or to issue commands to operate the computer.
- Spelling and grammar tools – web browser functions, plug-ins, or other software tools to help users write.
- Word prediction – software that presents selections of matching words, phrases, or sentences based on the current input (and sometimes context) to save typing.
- Reading assistants – software that changes the presentation of content and provides other functionality to make it more readable. Examples include: customizing the font type, size, spacing, or foreground and background colors; scanning the text for complex words and phrases, and linking them to glossaries; hiding less relevant parts of the content, such as sidebars and header areas; providing outlines of the page headings and summaries of the text passages; reading the content aloud and highlighting the text as it is being read out loud.
Adaptive strategies are techniques that everyone can use to improve interaction with websites or applications. Adaptive strategies can be used with standard software, mainstream web browsers, and with assistive technologies.
Examples of Adaptive Strategies
- Keyboard navigation – is for moving through content using the keyboard. This is often done by using the tab key to move between interactive elements such as links, form fields, or buttons. Keyboard navigation largely depends on web browser support but also on website or application design features.
- Customizing fonts and colors – includes changing the font types, sizes, colors, and spacing to make text easier to read. Customization involves browser settings and, for more advanced users, cascading style sheets (CSS) to override the default appearance of web content.
- Magnification – can include changing the settings of the web browser, operating system, or screen to enlarge or reduce text size and images. Some people use magnification lenses, binoculars, or other visual aids. Another common tool is screen magnification software that may allow text and mouse pointer enlargement and customization. Some operating systems allow for additional mouse pointer modifications, including controlling how fast the mouse moves, applying mouse trails to support tracking the mouse as it moves and the ability to visually locate the mouse pointer by pressing a key on the keyboard.
- Volume control – options can adjust the volume of audio content being played, including options to turn off the sound altogether. These controls may be separate from overall system settings.
- Synchronized Closed Captions – can be turned on for content that is either audio only or video with audio. They provide a text alternative that is synchronized with the media to show what is being spoken and to describe other sounds that are important to understanding the content conveyed through sound.
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