Making the Computer Accessible to You

By Dianna Lee

Making computer technology accessible is an integral practice in many environments, as a result of legislative changes and increased public awareness.

There are many options today for individuals who would like to use a computer but have a mobility impairment. Occupational therapists are trained to evaluate motor skills and related prerequisite skills required for functional competence. They work closely with rehabilitation engineers and speech language pathologists to help individuals identify the most appropriate access method to use and control technology.

Check for accessibility support services that might be available through the local hospital, university, community agency or place of employment.

Proper Seating and Positioning
As a first step towards making a computer accessible, proper seating and positioning should be considered. Upright back posture, with hips, knees and ankles positioned at 90 degrees of flexion, is generally considered to be suitable for desk work. Feet need to be well supported on the floor or with a footrest to distribute and reduce the load on the back of thighs and buttocks. The chair and table heights must be carefully assessed to achieve upright posture. The lower the chair, the more flexion or forward bending is seen in the lumbar region. Similarly, a low table promotes forward slumping of the back.

For individuals with muscle tone imbalance, extra supports such as pelvic straps, lateral controls for trunk balance or a head support may be needed.

Whatever the degree of impairment, attention to principles of good seating and positioning will result in improved access and overall reduced fatigue.

Optimal position or placement of the keyboard, mouse and monitor should also be considered. Ergonomic specialists suggest that the keyboard be at elbow height and the monitor about 18-28 inches from the user, with the display at eye level. It is generally agreed that the wrists should be in a neutral position to avoid repetitive strain injuries. A wrist support bar may be fabricated or purchased commercially and used to decrease stress in the wrist area when not typing.

Software enhancements
For motor-impaired individuals, one of the following software strategies may be helpful:
- Sticky Keys or Sequential Keystroke Input: For individuals who are unable to depress more than one key at a time, this function allows the user to enter keystrokes sequentially to produce the desired effect or function.
- Key Repeat Function: this feature allows the repeat function to be disengaged or the sensitivity of the keyboard to be adjusted for the user who has difficulty releasing keys.
- Macros: This feature involves preprogramming a few keystrokes to represent a number of single words, phrases, paragraphs or functions (e.g., GM = Good Morning).
- Word Prediction: Word prediction packages operate by anticipating the word the user will be typing and displaying a list of choices for the user. If the desired word appears, the user can select the word and have it entered onto the screen without having to type the word, or continue to type the next letter of the word.

Hardware Adaptations
Hardware strategies for motor-impaired individuals include:
- Keyguards: A keyguard is a template with holes matching keys of the standard keyboard. It fits over the keyboard to guide the fingers to the desired key or to provide stability for other fingers.
- Mouse Alternatives: Individuals who find grasping and manipulating a mouse difficult may use a trackball to control the cursor. Alternatively, some systems allow you to use the number pad to move the cursor. Keyboard equivalents may be also used to replace the mouse, depending on the software chosen.
- Point Devices: Optical, infrared or ultrasonic pointing devices that are mounted on the user’s head, cap or eyeglasses are used to point a light beam, reflector or transmitter at an on-screen keyboard for text input. These devices allow "hands-free" access to the computer as head movements are used to point to the keyboard on the screen.
- Alternative Keyboards: individuals who have limited range of motion in the shoulders and arms might benefit from a miniature keyboard where the keys are closely spaced. Individuals who have range of motion, but lack control due to involuntary movements or abnormal muscle tone, may use expanded keyboards. Expanded keyboards may be customized so that keys or targets are larger and spaced strategically. For both miniature and expanded keyboards, the option to customize the keyboard layout, so that keys used most frequently are located in the optimal location for a user’s needs, is an advantage.
- Morse Code Input: This involves using a single switch or set of switches to enter sequences of signals (dots and dashes) into the computer. For individuals with limited voluntary movement, Morse code input offers full access to the computer without using a keyboard.
- Scanning: Scanning is another method that uses one or more switches to select items from an array of letters presented on the screen. This method requires that the individual watch a highlighted cursor scan through the array and when the desired letter is highlighted, the user depresses the switch. Some switches are activated by an eye blink or eyebrow twitch while others, such as a "sip and puff" switch, involve an intake breath and an outward puff of air. The size of the switch, amount of pressure required to activate the switch, and tactile, kinaesthetic or auditory feedback provided by the switch are factors to consider when selecting a switch.
- Speech Input: Speech input or recognition systems are not new but have been improved so that individuals with significantly altered, but consistent, speech patterns can use speech for input to the computer. Many speech input systems have large word dictionaries and built-in word prediction strategies to make typing even more efficient.

Summary
Always ask if the method of access you wish to use requires a special interface, or if it plugs directly into the computer. Manufacturers and developers in the industry have attempted to integrate feedback from users and clinicians. As a result, less special hardware and less technical expertise are required to connect the user-friendly device or adaptation to the computer.


(Dianna Lee, M.A., B.Sc.OT(C) is with the Department of Occupational Therapy and the Institute for Research on Assistive Devices, Faculty of Applied Health Sciences, University of Western Ontario.)