 Visit 1. Preliminary investigations before the experiment starts, 1 session, maximum 3 hours pr session. Before the experiment starts, but after the participant has signed the informed consent, the investigators will test if the participant can tolerate the electrical stimulation.The evoked sensory feedback sensations over the hand, will be characterized by non-invasive, transcutaneous electrical stimulation of the peripheral nerves in different locations on the upper limb, both when stimulating single channel per at time, or several channels simultaneously. This session will allow to identify the electrical stimulation optimal parameters amplitude, frequency and pulse-width to induce sensations on the hand and how to modulate these sensations, close to natural pattern. A protocol to be integrated in a close-loop bidirectional control system of artificial hand will be developed. If all criteria for participation are fulfilled, the participation of the subject will be decided. 