Signals from skin mechanoreceptors used in control of a hand grasp neuroprosthesis.

We used signals from tactile mechanoreceptors in the skin of the index finger, recorded with an implanted cuff electrode, to automatically control grasp force in a hand grasp neuroprosthesis. Phasic events in the recorded nerve signal, related to mechanical events on the skin, were used to adjust electrical stimulation of hand muscles without any prior knowledge about muscle strength and properties of a held object. A simulated eating task was used to evaluate the hand grasp neuroprosthesis. When using the neuroprosthesis with feedback from natural sensors, the average grasp force could be reduced in comparison to not using feedback. Reducing grasp force is considered a major factor to decrease muscle fatigue, allowing a prolonged use of the hand grasp neuroprosthesis.