Mastering Tongue-Computer Interfaces: A Pilot Study on How Users Improve With Practice.

Tongue-operated input devices allow people with motor disabilities to interact with technology and their environment. Many such devices use barbell piercings to track the position of the tongue. Recent developments in tongue-computer interfacing have led to the proposal of a frame-integrated tracer that is not attached to the user's tongue. This study sought to investigate how an individuals ability to use their tongue to manipulate an integrated tracer evolves through use. Five people without motor disabilities and seven people with motor disabilities used a non-invasive inductive tongue-computer interface over six and three sessions, respectively. Among the individuals with motor disabilities were five people with spinal cord injury (SCI) and two men with amyotrophic lateral sclerosis (ALS). Their performance was evaluated at the start of each session using an intraoral target selection task. The participants with no motor disabilities showed a 26% improvement in median target selection time and a 15% improvement in median success rate. The median success rate for subjects with SCI improved by 40%, but the median target selection time stayed constant. Meanwhile, one participant with ALS increased his speed, while the other saw no substantial improvement. Furthermore, compared to the participants without disabilities, the participants with motor disabilities had a higher tendency to select the wrong target. Our findings provide further evidence that repeated use of a tongue-operated input device increases intraoral target selection speed and accuracy. Participants with motor disabilities may require longer dwell times to avoid unintentionally selecting targets when they move the activation unit.