Page 140 - Handbook of Electronic Assistive Technology

128 HANDBOOK OF ELECTRONIC ASSISTIVE TECHNOLOGY

Malcolm’s Case Study
Malcolm has quadriplegic cerebral palsy, which affects his fine motor control. To access his
computer, he uses an analogue USB joystick. He has some difficulty grasping the stick and
finds a T-bar handle slightly easier to manage. Malcolm uses his right hand on the stick and
his control movement utilises his whole arm rather than his fingers or his hand. The joystick
is fitted with a custom-made steel limiter plate that constrains the movement to be up,
down, left or right. Malcolm achieves very accurate control over the mouse pointer and he
can access everything on his computer independently. To click the mouse button, Malcolm
uses a wireless head switch. For typing, he uses an on-screen keyboard with predictor.

Nick’s Case Study
Nick is 19 years old and has quadriplegic cerebral palsy. He uses a membrane keyboard with
keyguard, and a BJOY switched joystick to control the mouse on his computer. The BJOY is
more effective for him than an analogue joystick because the acceleration is programmed
to give him slow speed on initial movement, which gives accurate fine control, and faster
speed when he holds the stick on, which gives him quicker movement around the screen.

Trackpads
Most laptops are fitted with a trackpad – a flat, touch-sensitive surface normally operated
using a finger: as you move your finger around the pad, the pointer moves correspond-
ingly. Trackpads are also available as separate pointing devices with USB connection
(Fig. 5-17). Trackpads are suitable for people who have difficulty holding or moving the
mouse, perhaps due to limited motor range or fatigue, but who have good finger dexterity.
People with motor neuron disease, RSI or arthritis may prefer a finger-operated touchpad
to a mouse or trackball because less movement is needed to operate it.

FIGURE 5-17 Easy Cat Touchpad�