Abstract
Many people with cerebral palsy work in social welfare companies as data entry operators etc. Because of spastic reactions and involuntary motion, they find it difficult to use their upper limbs for movement and positioning tasks such as pointing a mouse at an object on a GUI screen. It would be of great benefit to secure the movement distance and the target size which are appropriate for people with cerebral palsy on a GUI screen, so they can perform pointing device operation effectively. However, it is not possible to increase the screen size, beyond a certain limit. Therefore, ideal conditions may not be achieved. In such a situation, an effective environment for positioning tasks can be created by controlling the D/C gain, which is calculated by dividing the movement distance of the pointer by that of the input device. This study investigated the effect of changes in the D/C gain on motion time (MT) for pointing tasks and attempted to determine the D/C gain for minimizing the MT. It was found that the D/C gain for minimizing the MT could be obtained by using an appropriate combination of the target distance and target size.
