I work in Assistive Technology, which is technology designed to help people with disabilities stay independent.
We encountered a man who had quadriplegia due to a motor vehicle accident. He had a little motion in one hand and wanted to use a computer, but he could not use a regular mouse. If he could use the computer, he could go online, surf the internet, research whatever struck his fancy, chat with other people, email, etc. - it would open a lot of doors for him and greatly increase his standard of living. We tried a commercially available joystick mouse, and he could
use it successfully. The problem was cost: the commercial model was $550 (since then, it has dropped to $400
) which neither he nor his family could afford.
I built a joystick mouse for him out of a USB gamepad and arcade machine components. This mouse had two features lacking in the commercial model: 1) It could launch programs or commands, greatly increasing the efficiency of computer use 2) it could talk, giving auditory feedback regarding which button was pressed, as he could not move his head to look at his hands.
We have since used descendants of the first joystick mouse with several people who had cerebral palsy or other conditions that made traditional computer use difficult. The cost to build one of these is about $45.