A method to reversibly degrade proprioceptive feedback in research on human motor control

In research on human motor skills, it is often desirable to manipulate proprioceptive feedback in order to determine its contribution towards subjects' performance. Here we evaluate an easy-to-use, non-invasive method to temporarily reduce proprioceptive responsiveness. Two physiotherapy vibrators contacted the distal end of the subjects' forearm on the flexor and extensor side; they were either turned off, or they vibrated at 80 Hz with an amplitude of 1 mm. We found that vibration substantially impaired subjects' ability to use their hand in an angle matching, a force production and a haptic shape perception task. We also found that vibration strongly attenuated the H-reflex of the ipsilateral M. flexor carpi radialis. These results suggest that agonist-antagonist vibration is a useful method to degrade proprioceptive responsiveness for research on higher motor functions.