Assistive Technologies (AT) are hardware/software devices and applications that enable a person with a disability to effectively interact with computers. They are user specific accommodations that either facilitate or compensate for an individual's functional limitations to perform computer related input/output tasks. For information on assistive technology available at NC State check Office of Disability Services.
While assistive technology (AT) is a disability specific tool used by the individual, accessible technologies addresses the IT environment and resources. The design of the resource should be access-enabled, i.e.have accessibility features built into the resource so that it is compatible with assistive technologies and can be functional used by a person with disability regardless of their limitation or assistive technology used by them.
The following is a brief overview of the main categories of assistive technologies (AT) .
AT used by people who are blind, visual impaired or with other limitations perceiving or processing text (text impaired)
- Screen readers work closely with the operating system, relying on the systems built-in capabilities. They monitor system wide events; track insertion points and pointer position; maintain the identity, type, class and state of the focus object (element). They intercept information on changes to all elements that are being sent to the screen and retain in memory constructs known as off-screen model (OSM). This information is then conveyed to the user user via speech or tactile output. Talking browsers are similar to screen readers but are limited to reading web pages.
- Examples: JAWS by Freedom Scientific, WindowEyes by GW Micro, SuperNova by Dolphin Computer Access and Home Page Reader by IBM (example of a talking browser).
- Refreshable Braille Displays are electronic tactile devices that display Braille characters. They are used together with screen reading software where the output to the computer screen is sent as a line of Braille to the device connected to the computer via serial or USB ports. Refreshable Braille Devices usually consist of cells with eight retractable pins, 6 making up the Braille character and bottom 2 for information on attributes. These displays include directional and cursor routing keys which allow the user to navigate through a document. The displays range from an 20-cell to an 80-cell line.
- Examples: Power Braille, HandiTex
- Screen magnification software enlarges the size of information displayed on screen by a pre-determined incremental factor. They work with the standard controls of the operating system. Many screen magnification programs permit users to change the default colors, fonts and other attributes of the display and may also have inbuilt text-to-speech features. Typically, screen magnifiers track either the cursor or the active region of the screen.
- Examples: ZoomText by A1Squared, MAGic by Freedom Scientific and Lunar by Dolphin Computer Access.
AT used for Learning Disabilities (dyslexia, processing disabilities)
- Text-to-Speech software does not process any system information but just converts electronic text into aural output. These tools are often used by those who have some difficulty processing written text and need supplementary aural reinforcement.
- Examples: TextSpeech Pro, ReadPlease, Microsoft Reader, TextAloud and Natural Reader
- Reading Systems are integrated software packages that include tools like text-to-speech, OCR (optical character recognition) and screen magnification to help people who have difficulties reading, processing, comprehending and/or generating written information. These systems offer the user range of options for visual output: text magnification, text highlighting, limited blocks of text on the screen etc. while synchronizing the visual output with aural output. They can also include word prediction and other enhancements to help with text generation.
- Examples: WYNN from Freedom Scientific, Kurzweil 3000 from Kurzweil Education Systems and TextHelp from TextHelp Systems Inc
AT used for Text Input / Generation used by people with Physical Limitations
- Speech Recognition Technology interprets a user's spoken word and translates it into electronic text. The software is speaker-dependent and it needs to be “trained” by the user to create an acoustic model of their speech pattern. The recognition of the spoken word is based on a vocabulary of words used in context. The accuracy of the recognition is dependent on several factors including computer processing speed, quality of the microphone, the environment, the user's speech pattern and speaking rate.
- Examples: Dragon NaturallySpeaking from Nuance and ViaVoice from IBM
- Word prediction is a software tool that helps with text entry and is used by people with mobility and processing deficits. It consists of alphabetized lists of words and phrases that can be selected for entry into the text. Most learn the user’s frequency of use of words in context and suggests words back based on this frequency. Many include features like auto-correction, abbreviation expansion, keyboard macros/hotkey selection and speech. These features offer options to people who have mobility impairments or those who have trouble spelling or choosing the right word when writing. Word prediction tools are often integrated with other Reading /Literacy software, augmentative communication devices and other productivity software.
- Examples: WordQ from Quillsoft, Gus! Word Prediction from Gus Communication, Skippy from T&I Products and Co:Writer from Don Johnston
- Alternative Input Devices alternative keyboards, adaptive keyboards, touch-screen monitors, on-screen keyboards, mouse emulators (pointing devices) are all examples of devices adapted to perform input and mouse related tasks. They use direct keyboard access or keyboard equivalents to perform all tasks and functions. In addition, operating systems comes with built-in tools that allow the users to customize their keyboard to perform multi-key functions.
- Alternative Keyboards are specialized keyboards with alternative layouts like Dvorak, Colemak or stenotype, different sizes and shapes, with additional keys to perform special, functions, keys, wireless, virtual and other combinations to meet individuals functional capabilities.
- Keyboard Shrotcuts are combinations of modifier keys (alt, ctrl, shift, apple, cmd etc) and an alpha or numeric key that execute may click-and-point functions within an application. Keyboard shortcuts can be builtin or predefined within an application, be customized and/or can be created using an application's macro-building capabilities. KeyXL is an online keyboard shortcut database with shortcuts for Windows, Macintosh and Linux application.
