Eye-tracking technology has the potential to show cognitive processes involved in learning to use a multifunction prosthetic hand and to reveal gaze behaviors during tasks, according to a recent study. With that in mind, the team of researchers explored the use of eye tracking to study users’ learning progress at two points during rehabilitation. They concluded that a targeted prosthetic training protocol could help measure the functional benefits of multifunction hands.
Three people with amputations received control training of a multifunction hand and were assessed after one day of training and at one-year follow-up. During control training, the subjects learned three to four grips. The participants wore eye-tracking glasses and performed a set of standardized tasks that required them to change grips for each task. They also performed a self-chosen task in which they were free to use any grip for any object and were instructed to perform the task as they would normally do at home. The gaze-overlaid videos were analyzed and metrics were extracted for fixation duration, saccade amplitude, eye-hand latency, fixation count, and time to first fixation.
At the one-year follow-up, a decrease in performance time, fixation duration, eye-hand latency, and fixation count was observed in two subjects, indicating an improvement in the ability to control the multifunction hand and a reduction of cognitive load (data was missing for the third subject at the follow-up due to a socket problem). An increase in saccade amplitude was observed in both subjects, suggesting a decrease in difficulty controlling the prosthesis.
During the standardized tasks, the first fixations of all three subjects were on the multifunction hand in all objects. During the self-chosen tasks, the first fixations were mostly on the objects first.
The open-access study, “Using eye tracking to assess learning of a multifunction prosthetic hand: an exploratory study from a rehabilitation perspective,” was published in the Journal of NeuroEngineering and Rehabilitation.
