The influence of haptic guidance on the production of spatio-temporal patterns

Haptic guidance by a robot is a recent technology to support motor learning. Its mechanisms and effects are not yet well understood. One of the hypotheses is that learning of temporal characteristics is particularly susceptible to the beneficial effects of robotic guidance. In this study we investigate the influence of robotic guidance on the production of spatio-temporal patterns. Participants practiced to draw circles with the velocity profile of ellipses. Performance during the practice phase, when participants were assisted by a robotic device, as well as during the test phase, when assistance was switched off, was compared to a control group. During practice participants with robotic assistance performed better on all three dependent measures, shape, timing of the velocity modulation, and modulation amplitude. However, these differences between groups largely disappeared in the test phase. Only the difference in the amplitude of the velocity modulation remained, which was more accurate in the robot-guidance group than in the control group. This remaining difference likely results from a secondary effect of robotic guidance, namely the experience of smaller visual errors and weaker velocity modulations during practice.