Error encoded vibrotactile feedback to enhance motor adaptation

The study of how humans learn a skilled movement and how they are able to compensate changes in the environment’s dynamics is a topic of extreme interest, with a wide range of possible applications. Amplification of the error made while performing a task has been shown to be an effective technique to accelerate the learning process. The aim of this study is to present a preliminary investigation to understand if this technique works because it increases the subjects’ awareness of error. Thanks to a modern Virtual Reality system, we studied if it is possible to enhance motor adaptation by providing to the subjects a vibrotactile feedback which is proportional only to the magnitude of the error. Our study asked 16 healthy subjects to perform a reach-and-stop task with their dominant hand, in a virtual reality environment where the visual field was rotated by 60 degrees. Our data shows that all the subjects were able to compensate the visual distortion, and to transfer what they learned to novel targets. The subjects who received the vibrotactile feedback were able to compensate the visual distortion almost twice as fast as the subjects of the control group. The results of this experiment suggest that a vibrotactile feedback has the potential to speed-up the adaptation. Further studies are necessary to better understand how to maximize the beneficial effect of vibration and to compare the effect of the vibrotactile feedback with the effect of other well known techniques used to enhance motor adaptation.