Background: Microswitches are the most commonly used input device for people with multiple disabilities to control environmental stimulation. However, little is known about adopting the commercial trackball with a revised trackball driver as a more feasible input device. Aims: To assess whether two children with profound multiple disabilities and minimal motor skills would be able to control environmental stimulation using thumb poke ability through cordless trackballs installed with a newly developed mouse driver (i.e. a new mouse driver replacing a standard mouse driver, turning a trackball mouse into a precise thumb poke detector). Method: An ABAB design and a 2-month post-intervention check were adopted to perform the study. Results: Data showed that the two children improved significantly in their target response (thumb poke) to activate the control system to produce environmental stimuli during the B (intervention) phases. This performance was maintained at the post-intervention check. Conclusions: The use of thumb poke in connection with a trackball allowed the children with multiple disabilities and minimal motor skills to increase their level of response and stimulation control.

We assessed the use of a microswitch cluster to improve assisted ambulation in a man with multiple disabilities. The cluster included two optic microswitches at the man's heels to detect his steps and a pressure microswitch under his right arm to detect his body posture (i.e. whether he had an upright, appropriate posture or was leaning forward). The man received 2.5 seconds of favourite stimulation at each step provided that his posture was appropriate. The results showed that there was a large increase in the man's appropriate posture during walking throughout the intervention phases and the 3-month follow-up.

Selecting a convenient response, and a microswitch suitable to it, is critical to successfully introduce students with multiple disabilities to a microswitch-aided programme. This study evaluated the use of a hand-tap response with a vibration microswitch with two students. Both students increased the frequency of the hand-tap response during treatment and maintained such an increase at 3-month follow-up. Procedural issues, practical implications of the findings, and measures for promoting long-term response maintenance/extensions were discussed.