Optimizing Assisted Communication Devices for Children With Motor Impairments Using a Model of Information Rate and Channel Capacity

The subjects were required to touch targets on the iPad® screen with the index finger of their preferred (less-affected) arm. The experimental task consisted of 180 targets divided in 4 blocks: 45 targets each block with a 1-minute interval between trials to avoid fatigue. Targets appeared at 1 of 9 different locations on the screen, and subjects moved their finger sequentially from one target to the next.