This list of assistive technologies is not exhaustive. There are a great many more types of technologies for motor disabilities than are listed here, but we have listed some of the major types so as to acquaint you with the kinds of issues that people with motor disabilities face. Designers do not need to know everything about every kind of motor disability or assistive technology in order to design web content accessible to this population. Despite the broad range of motor disability types, many of them result in similar technological needs with regard to computer access. Some of the more common types of assistive technologies for people for motor disabilities are found below.
A mouth stick is just what its name implies: a stick that is placed in the mouth. Due to its simplicity and low cost, the mouth stick is one of the most popular assistive technologies (though the word "technology" may a bit of an overstatement in this instance). In many cases there is a rubber tip at the end of the mouth stick to give the tip better traction, and a plastic or rubber feature at the other end that the person inserts into the mouth. Someone with no use of the hands could use a mouth stick to type and perhaps to manipulate a trackball mouse, depending on the amount of control that the person has with the mouth stick, and on the amount of patience that the person has if these movements are difficult.
Head wands are very similar in function to mouth sticks, except the stick is strapped to the head. A person moves the head to make the head wand type characters, navigate through web documents, etc. Fatigue can be an issue when a lot of keystrokes are required in order to accomplish a task.
People who have very limited mobility use this type of device. If a person can move only the head, for example, a switch could be placed to the side of the head that would allow the person to click it with head movements. This clicking action is usually interpreted by special software on the computer, allowing the user to navigate through the operating system, web pages, and other environments. Some software facilitates the typing of words by using an auto-complete feature that tries to guess what the person is typing, and allowing the person to choose between the words that it guesses.
Sip and puff switch
Similar in functionality to the single switch described above, sip and puff switches are able to interpret the user's breath actions as on/off signals, and can be used for a variety of purposes, from controlling a wheelchair to navigating a computer. The hardware can be combined with software that extends the functionality of this simple device for more sophisticated applications.
Oversized trackball mouse
A trackball mouse is not necessarily an assistive technology—some people without disabilities simply prefer it to the standard mouse—but it is often easier for a person with a motor disability to operate than a standard mouse. Someone may, for example, use a trackball mouse in conjunction with a head wand or mouth stick. It is relatively easy to manipulate a trackball with these devices and much harder to manipulate a standard mouse. Someone with tremors in the hands may also find this kind of mouse more useful because once the person moves the mouse cursor to the right location, there is less danger of accidentally moving the cursor while trying to click on the mouse button. A person with tremors in the hands could also manipulate the trackball mouse with a foot, if there is enough motor control in the feet.
In cases where a person does not have reliable muscle control in the hands for precision movements, an adaptive keyboard can be useful. Some adaptive keyboards have raised areas in between the keys, rather than lowered areas, to allow the person to first place the hand down on the keyboard, then slide the finger into the correct key. A person with tremors, or spastic movements could benefit from this type of keyboard. Keyboard overlays are also available as an adaptation to standard keyboards, which achieve the same results. In some cases, adaptive keyboards come with specialized software with word-completion technology, allowing the person to type with fewer keystrokes, since typing can be rather laborious and slow otherwise.
A web-based word on-screen keyboard with word completion technology can be found at http://www.enetplanet.com/kb_fr/. In nearly all cases, people who need this technology will have it installed on their own computer, rather than using a Web-based version, but an online version can be useful when users are away from their regular computer. It can also be a useful tool to help developers understand how this particular type of technology works.
Eye tracking devices can be a powerful alternative for individuals with no control, or only limited control, over their hand movements. The device follows the movement of the eyes and allows the person to navigate through the web with only eye movements. Special software allows the person to type, and may include word-completion technology to speed up the process. These systems can be expensive—usually in the thousands of US dollars—so they are less common than the less sophisticated devices, such as mouth sticks and head wands.
Voice recognition software
Another alternative is to install software that allows a person to control the computer by speaking. This assumes that the person has a voice that is easy to understand. Some people with motor disabilities—those with cerebral palsy in particular—may have a difficult time speaking in a way that the software can understand them, since the muscles that control the voice are slow to respond, and speech is often slurred, despite the fact that these people do not have any slowness in their mental capacity.
Other assistive technologies
The assistive technologies listed above are some of the more prevalent technologies, but there are literally thousands of products available for a wide range of motor disabilities. Despite this wide variety, there is one key point to keep in mind:
Most assistive technologies for people with motor disabilities either work through the keyboard or emulate the functionality of the keyboard.
Knowing this, developers can focus on making their content accessible to the keyboard, and ensure that the site is navigable with as few keystrokes as possible.