<qa>  What is the name of the device that will give the arm a power-assisIn this study, patients may be administered a new robotic brace as part of treatment for their affected arms. If they use this brace, your electromyography EMG signals will be used to control the powered arm brace. EMG signals are the small electrical signals that result from the actions of the muscles. The system will listen to patients muscles, using small sensors that sit on top of the skin. The device will give the arm a power-assist when patients bend or straighten their elbows. The investigators want to test how easy and effective this system is to use. The investigators hypothesize that people using the robot will be more successful in their rehabilitative efforts - and that their movement will improve more - than people receiving traditional therapy. 