Effects of 2D/3D visual feedback and visuomotor collocation on motor performance in a Virtual Peg Insertion Test

This paper evaluates the influence of three different types of visual feedback on the motor performance of healthy subjects during the repeated execution of a Virtual Peg Insertion Test developed for the assessment of sensorimotor function of arm and hand in neurologically impaired subjects. One test trial consists of the grasping and insertion of 9 pegs into 9 holes using a haptic display with instrumented grasping handle. Three groups performed 10 trials initially on three different setups (group 1 with standard 2D visual feedback, group 2 with 3D, and group 3 with collocated 3D visual feedback) followed by 10 more trials with the setup with 2D visual feedback. The total execution time and the mean collision force as well as the time and the collision force for 6 different movement phases were compared between groups and analyzed in function of the number of repetitions. Results showed significantly lower time to approach and align the visual cursor with the peg with the 2D setup over the first 10 trials compared to the two other groups, suggesting limitations of the 3D setup. Furthermore, a significant decrease of the total execution time was found in the first 10 trials for all groups. For the 10 following trials, only group 3 showed a significant decrease in the total execution time, suggesting that the learning did not transfer to the 2D setup for this group.