For Visual Impairments
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Screen enlargers (or screen magnifiers) work like a magnifying glass. They enlarge a portion of the screen, increasing the legibility for some users. Some screen enlargers allow a person to zoom in and out on a particular area of the screen.
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Screen readers are software programs that present graphics and text as speech. For a computer user who is blind, and does not need a monitor, a screen reader is used to verbalise, or "speak," everything on the screen including names and descriptions of control buttons, menus, text, and punctuation. In essence, a screen reader transforms a graphic user interface (GUI) into an audio interface.
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Speech recognition systems, also called voice recognition programs, allow people to give commands and enter data using their voices rather than a mouse or keyboard. Voice recognition systems use a microphone attached to the computer, which can be used to create text documents such as letters or e-mail messages, browse the Internet, and navigate among applications and menus by voice. Speech recognition systems are also used by people with language and learning disabilities who have difficulty typing or reading text.
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Speech synthesizers receive information going to the screen in the form of letters, numbers, and punctuation marks, and then "speak" it out loud. Often referred to as text-to-speech (TTS), the voice of the computer is synthesized speech—a distinctive, sometimes monotone voice that is the joining together of pre-programmed letters and words. Using speech synthesizers allows blind users to review their input as they type. Speech synthesizers are also used by people with language and learning impairments, for example, those who are unable to communicate orally.
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Refreshable Braille displays provide tactile output of information represented on the computer screen. A Braille "cell" is composed of a series of dots. The pattern of the dots and various combinations of the cells are used in place of letters. Refreshable Braille displays mechanically lift small rounded plastic or metal pins as needed to form Braille characters. The user reads the Braille letters with his or her fingers, and then, after a line is read, can refresh the display to read the next line.
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Braille embossers transfer computer generated text into embossed Braille output. Braille translation programs convert text scanned in or generated via standard word processing programs into Braille, which can be printed on the embosser.
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Talking and large-print word processors are software programs that use speech synthesizers to provide auditory feedback of what is typed. Large-print word processors allow the user to view everything in large text without added screen enlargement. Individuals with learning disabilities often use these special-featured word processors to assist them with their spelling and grammar and/or to provide the auditory feedback they require to be able to write.
For Mobility Impairments
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On-screen keyboard programs provide an image of a standard or modified keyboard on the computer screen. The user selects the keys with a mouse, touch screen, trackball, joystick, switch, or electronic pointing device. On-screen keyboards often have a scanning option. With the scanning capability turned on, the individual keys on the on-screen keyboard are highlighted. When a desired key is highlighted, an individual with a mobility impairment is able to select it by using a switch positioned near a body part that is under his or her voluntary control.
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Keyboard filters include typing aids such as word prediction utilities and add-on spelling checkers. These products reduce the required number of keystrokes. Keyboard filters enable users to quickly access the letters they need and to avoid inadvertently selecting keys they don't want. Keyboard filters—especially word prediction and spelling checkers—are also used by people with language and learning impairments.
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Touch screens are devices placed on the computer monitor (or built into it) that allow direct selection or activation of the computer by touching the screen. These devices can benefit some users with mobility impairments because they present a more accessible target. It is easier for some people to select an option directly rather than through a mouse movement or keyboard because that movement might require greater fine motor skills than simply touching the screen to make a selection. Other people with mobility impairments might make their selections with assistive technology such as mouth sticks. Touch screens are also used by people with language and learning impairments who find it a more simple, direct, and intuitive process than making a selection using a mouse or keyboard.
Alternative input devices allow individuals to control their computers through means other than a standard keyboard or pointing device. Examples include:
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Alternative keyboards—those with larger- or smaller-than-standard keys or keyboards, alternative key configurations, and keyboards for use with one hand.
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Electronic pointing devices—used to control the cursor on the screen using ultrasound, an infrared beam, eye movements, nerve signals, or brain waves.
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Sip-and-puff systems—activated by the user's breath.
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Wands and sticks—used to strike keys on the keyboard (usually worn on the head, held in the mouth, strapped to the chin).
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Joysticks—manipulated by hand, feet, chin, etc. and used to control the cursor on screen.
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Trackballs—movable balls on top of a base that can be used to move the cursor on screen.
For Language Impairments
Screen review utilities make on-screen information available as synthesized speech and pairs the speech with a visual representation of a word, for example, highlighting a word as it is spoken. Screen review utilities convert the text that appears on screen into a computer voice. This helps some people with language impairments. Some individuals with learning impairments find speech recognition easier to use for writing text. Additional assistive technology products used with computers by people with language impairments also include others, which are defined above:
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Keyboard filters
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Speech recognition programs
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Touch screens
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Speech synthesizers
For Learning Impairments
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Word prediction programs allow the user to select a desired word from an on-screen list located in the prediction window. This list, generated by the computer, predicts words from the first one or two letters typed by the user. The word can then be selected from the list and inserted into the text by typing a number, clicking the mouse, or scanning with a switch. These programs help users increase vocabulary skills through word prompting.
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Reading comprehension programs focus on establishing or improving reading skills through ready-made activities, stories, exercises, or games. These programs can help users practice letter sound recognition and can increase the understanding of words by adding graphics, sound, and possibly animation.
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Reading tools and learning disabilities programs include software designed to make text-based materials more accessible for people who have difficulty with reading. Options can include scanning, reformatting, navigating, or speaking text out loud. These programs help people who have difficulty seeing or manipulating conventional print materials; people who are developing new literacy skills or who are learning English as a foreign language; and people who comprehend better when they hear and see text highlighted simultaneously.
Additional assistive technology products used with computers by people with learning impairments also include products defined above including:
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Speech synthesizers
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Speech recognition programs
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Talking and large print word processors