Researchers at the University of Washington have developed a self-optimising graphical interface for disabled computer users.

"Assistive technologies are built on the assumption that it's the people who have to adapt to the technology," said computer scientist Krzysztof Gajos. "We tried to reverse this assumption, and make the software adapt to people."

The University claims that the system closed the performance gap between disabled and able-bodied users by 62%, and that test showed disabled users strongly preferred the automatically generated interfaces.

Called Supple, the system requires a single assessment of a person's mouse pointing, dragging and clicking skills.

Tests include a ring of dots on the screen. As each dot lights up, the user must click on it. The task is repeated with different-sized dots.

Another test prompts the participant to click and drag, select from a list, and click repeatedly on one spot.

Participants can move the cursor using any type of device.

"The test takes about 20 minutes for an able-bodied person or up to 90 minutes for a person with motor disabilities," said the University.

Supple creates an interface that increases a person's accuracy and speed when using a particular program.

The University released two examples of optimisation following tests with six able-bodied people and 11 with motor impairments:

A man with cerebral palsy used his chin to control a tracker ball and could move the pointer quickly but jerkily. "Supple generated a user interface where all the targets were bigger than normal, and lists were expanded to minimise scrolling," said the University.

A woman with muscular dystrophy used both hands to move a mouse. "She could make very precise movements but moved the cursor very slowly and with great effort because of weak muscles", said the University.

For her, Supple generated an interface with small buttons and a compressed layout.

"There is a temptation to think that we can come up with a universal design. But if we look at the results, the design that helps one person will actually be hurtful to a person with a different set of abilities," said Gajos.