| Abstract: |
An alternating treatments design was implemented to compare two selection techniques used in augmentative and alternative communication systems: scanning and direct selection. Specifically, use of inverse circular scanning and direct selection (using a head-mounted optical pointer) by a child with severe physical limitations was compared across response accuracy, acquisition rate, and response time. Results indicated that direct selection was more effectively used by the child across all three dimensions, even though preassessment information predicted that scanning should be a more appropriate technique. Off-task and attentional fatigue issues seemed to play a role in determination of the most appropriate match between selection technique demands and child skills and limitations. |
