Evaluation of the effects of adding vibrotactile feedback to myoelectric prosthesis users on performance and visual attention in a dual-task paradigm

Abstract

Myoelectric prostheses inherently lack tactile feedback. Therefore, users of these devices have to rely on their visual feedback. Since daily tasks are often performed in a dual-task paradigm, e.g. holding a coffee cup while reading a newspaper or folding clothes while watching the television, they pose a cognitive challenge to the prosthesis user. Our objective was therefore to evaluate the effects of adding vibrotactile feedback to myoelectric prosthesis users on the performance time and visual attention in a dual-task paradigm. Twelve transradial amputees using a myoelectric prosthesis (age 65 ± 13 years) performed five functional grasping tasks with their prosthetic hand, while controlling a virtual car on a road with their intact hand. The dual-task was performed twice: with and without vibrotactile feedback. We measured the performance time of each of the grasping tasks and gaze behavior, measured by the number of times the subjects shifted their gaze towards their hand, the relative time they applied their attention to the screen, and the percentage of error in the virtual driving task. The mean performance time was significantly shorter ( P = .024) when using vibrotactile feedback (93.2 ± 9.6s) compared with the performance time measured when vibrotactile feedback was not available (107.8 ± 20.3s). No significant differences were found between the two conditions in the number of times the gaze shifted from the screen to the myoelectric hand, in the time the subjects applied their visual attention to the screen, and in the total time that the virtual car was off-road with and without vibrotactile feedback, as a percentage of the total game time (51.4 ± 15.7 and 50.2 ± 19.5, respectively). Tactile feedback can be an effective addition to myoelectric prosthesis users, improving performance time during grasping and manipulating objects in a dual-task paradigm.