RecruitingDevice studyCan an Array of Micro-electrodes Implanted in a Human Nerve Record Neural Signals and Provide Feedback?The investigators will investigate the device feasibility of human peripheral nerves and muscles recording and stimulation using percutaneous Utah Slanted Electrode Arrays (pUSEAs) implanted into residual peripheral arm nerves and EMG electrodes implanted in the residual muscles of patients with limb amputations in order to determine the ability of the HAPTIX (Hand Proprioception and Touch Interfaces) System to control an upper-extremity prosthesis, and to provide a sense of cutaneous touch and muscle proprioceptive feedback to the amputee.