Assistive technology

Assistive technology

Assistive technology (AT) is a generic term that includes assistive, adaptive, and rehabilitative devices for people with disabilities and includes the process used in selecting, locating, and using them.

AT promotes greater independence by enabling people to perform tasks that they were formerly unable to accomplish, or had great difficulty accomplishing, by providing enhancements to or changed methods of interacting with the technology needed to accomplish such tasks.

However, Cook & Hussey (2001) [Cook, A.M. and Hussey, S. Assistive Technologies: Principles and Practice (2nd Edition) Publisher: Mosby ISBN 0323006434, 2001] report this term is usually not used for rehabilitative devices and for devices that non-disabled people find useful.

Likewise, disability advocates point out that technology is often created without regard to people with disabilities, creating unnecessary barriers to hundreds of millions of people.

Assistive technology and universal accessibility

Universal (or broadened) accessibility, or universal design means greater usability, particularly for people with disabilities.

Universally accessible technology yields great rewards to the typical user as well; good accessible design "is" universal design. One example is the "curb cuts" (or dropped curbs) in the sidewalk at street crossings. While these curb cuts enable pedestrians with mobility impairments to cross the street, they also aid parents with carriages and strollers, shoppers with carts, and travellers and workers with pull-type bags.

As an example, the modern telephone is inaccessible to people who are deaf or hard of hearing. Combined with a text telephone (also known as a TDD Telecommunications device for the deaf and in the USA generally called a TTY [TeleTYpewriter] ), which converts typed characters into tones that may be sent over the telephone line, a deaf person is able to communicate immediately at a distance. Together with "relay" services, in which an operator reads what the deaf person types and types what a hearing person says, the deaf person is then given access to everyone's telephone, not just those of people who possess text telephones. Many telephones now have volume controls, which are primarily intended for the benefit of people who are hard of hearing, but can be useful for all users at times and places where there is significant background noise. Some have larger keys well-spaced to facilitate accurate dialling.

Also, a person with a mobility impairment can have difficulty using calculators. Speech recognition software recognizes short commands and makes use of calculators easier.

People with learning disabilities like dyslexia or dysgraphia are using text-to-speech (TTS) software for reading and spelling programs for assistance in writing texts.

Computers with their peripheral devices, editing, spellchecking and speech synthesis software are becoming the core-stones of the assistive technologies coming for relief to the people with learning disabilities and to the people with visual impairments. The assisting spelling programs and voice facilities are bringing better and more convenient text reading and writing experience to the general public.

Toys which have been adapted to be used by children with disabilities may have advantages for non-disabled children as well. The Lekotek movement assists parents by lending assistive technology toys and expertise to families.

Assistive technology products


Telecare is a particular sort of assistive technology that uses electronic sensors connected to an alarm system to help caregivers manage risk and help vulnerable people stay independent at home longer. An example would be the systems being put in place for senior people such as fall detectors, thermometers (for hypothermia risk), flooding and unlit gas sensors (for people with mild dementia). Notably, these alerts can be customized to the particular person's risks. When the alert is triggered, a message is sent to a carer or contact centre who can respond appropriately.

Technology similar to Telecare can also be used to act within a person's home rather than just to respond to a detected crisis. Using one of the examples above, gas sensors for people with dementia can be used to trigger a device that turns off the gas and tells someone what has happened.

Designing for people with dementia is a good example of how the design of the interface of a piece of AT is critical to its usefulness. People with dementia or any other identified user group must be involved in the design process to make sure that the design is accessible and usable. In the example above, a voice message could be used to remind the person with dementia to turn off the gas himself, but whose voice should be used, and what should the message say? Questions like these must be answered through user consultation, involvement and evaluation.

Accessible computer input

Sitting at a desk with a QWERTY keyboard and a mouse remains the dominant way of interacting with a personal computer. Some Assistive Technology reduces the strain of this way of work through ergonomic accessories with height-adjustable furniture, footrests, wrist rests, and arm supports to ensure correct posture. Keyguards fit over the keyboard to help prevent unintentional keypresses.

Alternatively, Assistive Technology may attempt to improve the ergonomics of the devices themselves:
* Ergonomic keyboards reduce the discomfort and strain of typing.
* Chorded keyboards have a handful of keys (one per digit per hand) to type by ‘chords’ which produce different letters and keys.
* Expanded keyboards with larger, more widely-spaced keys.
* Compact and miniature keyboards.
* Dvorak and other alternative layouts may offer more ergonomic layouts of the keysFact|date=May 2008. There are also variants of Dvorak in which the most common keys are located at either the left or right side of the keyboard.

Input devices may be modified to make them easier to see and understand:
* Keyboards with lowercase keys
* Keyboards with big keys.
* Large print keyboard with high contrast colors (such as white on black, black on white, and black on ivory).
* Large print adhesive keyboard stickers in high contrast colors (such as white on black, black on white, and black on yellow).
* Embossed locator dots help find the ‘home’ keys, F and J, on the keyboard.
* Scroll wheels on mice remove the need to locate the scrolling interface on the computer screen.
* Footmouse - Foot-operated mouse.

More ambitiously, and quite crucially when keyboard or mouse prove unusable, AT can also replace the keyboard and mouse with alternative devices: trackballs, joysticks, graphics tablets, touchpads, touch screens, foot mice, a microphone with speech recognition software, sip-and-puff input, switch access, and vision-based input devices.

Software can also make input devices easier to use:

* Keyboard shortcuts and MouseKeys allow the user to substitute keyboarding for mouse actions. Macro recorders can greatly extend the range and sophistication of keyboard shortcuts.
* Sticky keys allows characters or commands to be typed without having to hold down a modifier key (Shift, Ctrl, Alt) while pressing a second key. Similarly, [ ClickLock] is a Microsoft Windows feature that remembers a mouse button is down so that items can be highlighted or dragged without holding the mouse button down throughout.
* Customization of mouse or mouse alternatives' responsiveness to movement, double-clicking, and so forth.
* [ ToggleKeys] is a feature of Microsoft Windows 95 onwards. A high sound is heard when the CAPS LOCK, SCROLL LOCK, or NUM LOCK key is switched on and a low sound is heard when any of those keys are switched off.
* Customization of pointer appearance, such as size, color and shape.
* Predictive text
* Spell checkers and grammar checkers

Durable Medical Equipment (DME)

* Seating products that assist people to sit comfortably and safely (seating systems, cushions, therapeutic seats).
* Standing products to support people with disabilities in the standing position while maintaining/improving their health (standing frame, standing wheelchair, active stander).
* Walking products to aid people with disabilities who are able to walk or stand with assistance (canes, crutches, walkers, gait trainers).
* Advanced technology walking products to aid people with disabilities, such as paraplegia or cerebral palsy, who would not at all able to walk or stand (exoskeletons).
* Wheeled mobility products that enable people with reduced mobility to move freely indoors and outdoors (wheelchairs, scooters)

Learning difficulties

* Age-appropriate software
* Cause and effect software [cite web
coauthors=Jones, Melanie
title=Using Computer Software To Develop Switch Skills
work=2003 [Technology and Persons with Disabilities] Conference Proceedings
* Hand-eye co-ordination skills software
* Diagnostic assessment software
* Mind mapping software
* Study skills software
* Symbol-based software [cite web
coauthors=Blenkhorn, Paul
title=Bridging the Gap between Aspiration and Capability for Aphasic and Brain Injured People
work=2002 [Technology and Persons with Disabilities] Conference Proceedings
* Text-to-speech
* Touch typing software

Visual impairment

Choice of appropriate hardware and software will depend on the user's level of functional vision.

* RIAS (Remote Infrared Audible Signage) has the potential to help both low vision and the blind navigate outside and indoors.


* Large monitors.
* Adjustable task lamp, using a fluorescent bulb, shines directly onto the paper and can be adjusted to suit.
* Copyholder holds printed material in near vertical position for easier reading and can be adjusted to suit.
* Closed circuit television (CCTV) or video magnifier. Printed materials and objects are placed under a camera and the magnified image is displayed onto a screen.
* Modified cassette recorder. To record a lecture, own thoughts, ideas, notes etc.
* Desktop compact cassette dictation system. To allow audio cassette playback with the aid of a foot pedal.
* Fusers produce tactile materials, for example diagrams and maps, by applying heat to special swell paper.
* Scanner. A device used in conjunction with OCR software. The printed document is scanned and converted into electronic text, which can then be displayed on screen as recognisable text.
* Standalone reading aids integrate a scanner, optical character recognition (OCR) software, and speech software in a single machine. These function together without a separate PC. [cite web
title = What is a reading aid – technology information sheet
publisher = [ Royal National Institute for the Blind]
url =
date = 2006-09-29
accessdate = 2007-02-08
* Refreshable Braille display. An electronic tactile device which is placed below the computer keyboard. A line of cells which correspond to Braille text move up and down to represent a line of text on the computer screen.
* Electronic Notetaker. A portable computer with a Braille or QWERTY keyboard and synthetic speech. Some models have an integrated Braille display.
* Braille embosser. Embosses Braille output from a computer by punching dots onto paper. It connects to a computer in the same way as a text printer.
* Perkins Brailler. To manually emboss Grade 1 or 2 Braille.


* Customization of graphical user interfaces to alter the colors and size of desktops, short-cut icons, menu bars and scroll bars.
* Screen magnifiers
* Screen readers
* Self-voicing applications
* Optical character recognition. Converts the printed word into text, via a scanner.
* Braille translation. Converts the printed word into Braille, which can then be embossed via a Braille embosser.
* Text-to-speech and Speech-to-text
* Spell checkers and Grammar checkers

Augmentative and Alternative Communication (AAC)

Augmentative and alternative communication is a well defined specialty within AT.AAC devices vary widely with respect to their technological sophistication:

* Low-tech systems. Simple paper or object based systems, i.e. do not require a battery.
* Light-tech systems. Typically consisting of a digitized speech recorder with a touch-sensitive display pad and sometimes switch access. Lite-tech systems require a battery.
* High-tech systems. Computerized VOCAs that vary from single purpose appliance-like systems to multipurpose computer-based communication aids. Typically high-tech systems require training and ongoing support to operate the devices.

Deafness and hearing loss

* Audiometer
* Fire alarm paging system
* Loop system (portable and fixed)
* Radio aids
* Telecommunications device for the deaf
* Teletext
* Video cassette recorders that can read and record subtitles (Closed Captioning).
* Vibrating fire alarm placed under pillow when asleep.
* Door bell lighting system.


* Wakamaru provides companionship, reminds users to take medicine and calls for help if something is wrong.
* CARE (Call Reassurance) community based program that calls seniors at home ensuring their well-being [] .
* Cosmobot is part of a play therapy system designed to motivate children to participate in therapy.


ee also

* Computer accessibility
* Web accessibility

Further reading

* Behrmann, M. & Schaff, J.(2001). Assisting educators with assistive technology: Enabling children to achieve independence in living and learning. Children and Families 42(3), 24-28.

* Bishop, J. (2003). The Internet for educating individuals with social impairments. Journal of Computer Assisted Learning 19(4), 546-556. Available as a free [ download]

* Cain, S. (2001). Accessing Technology - Using technology to support the learning and employment opportunities for visually impaired users. Royal National Institute for the Blind. ISBN 1-85878-517-0.

* Cook, A., & Hussey, S. (2002). Assistive Technologies - Principles and Practice, 2nd Edition. Mosby. ISBN 0-323-00643-4

* Franklin, K.S. (1991). Supported employment and assistive technology-A powerful partnership. In S.L. Griffin & W.G. Revell (Eds.), Rehabilitation counselor desktop guide to supported employment. Richmond, VA: Virginia Commonwealth University Rehabilitation Research and Training Center on Supported Employment.

* Van der Heijden, D. (2005). How Does Alternative Access to Computers Work? Available as an [ online article] .

* Lahm, E., & Morrissette, S. (1994, April). Zap 'em with assistive technology. Paper presented at the annual meeting of The Council for Exceptional Children, Denver, CO.

* Lee, C. (1999). Learning disabilities and assistive technologies; an emerging way to touch the future. Amherst, MA: McGowan Publications.

* McKeown, S. (2000). Unlocking Potential - How ICT can support children with special needs. The Questions Publishing Company Ltd. ISBN 1-84190-041-9

* Nisbet, P. & Poon, P. (1998). Special Access Technology. The CALL Centre, University of Edinburgh. Available as a free [ download] The CALL Centre. ISBN 1-898042-11-X

* Nisbet, P., Spooner, R., Arthur, E. & Whittaker P. (1999). Supportive Writing Technology. The CALL Centre, University of Edinburgh. Available as a free [ download] The CALL Centre. ISBN 1-898042-13-6

* Rose, D. & Meyer, A. (2000). Universal design for individual differences. Educational Leadership, 58(3), 39-43.

* Orpwood, R. Design methodology for aids for the disabled. J Med Eng Technol. 1990 Jan-Feb;14(1):2-10. | [ PubMed ID: 2342081]

* Adlam, T. et al. The installation and support of internationally distributed equipment for people with dementia." IEEE transactions on information technology in biomedicine (1089-7771) yr:2004 vol:8 iss:3 pg:253-257 | [ download from IEEE (694k PDF)]

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