This study provides an exciting demonstration of the multiple DOF control that is possible by combining targeted muscle reinnervation electromyographic control signals, residual limb electromyographic control signals, and conventional shoulder switches and force sensing resistors. With this new device the subject was able to easily control 2 DOF simultaneously in many different combinations. Control of 3 DOFs was not quantified but clinically observed. Three DOFs seemed harder to control concurrently, but were possible for gross movements such as reaching out with the arm (elbow and shoulder) while opening the hand. Additionally, simultaneous actuation of 4 DOFs was theoretically possible but rarely done because the device does not provide any proprioceptive feedback, so positioning this many DOFs required significant cognitive demands.It is acknowledged that this is not an ideal control system and that the cognitive demand is still great. This is confirmed by the fact that the subject rarely used more than 2 motors at a time, even though it was theoretically possible for him to operate 4, and he preferred to use the limbs at relatively slow speeds. This cognitive demand will undoubtedly remain great for high level amputees due to the lack of proprioceptive feedback and the need to use visual feedback to place the device. However, this may not negate the benefits of additional control signals with more physiologically appropriate control