All subjects receive the same active robotic therapy, there is no placebo arm, as a key goal of this study is to define predictors of response to active treatment.

Treatment occurs in 2 hour sessions, 4 times a week over 3 weeks. In each treatment session, you will sit in a chair and have your weak hand attached to a mechanical device (the robot), which will help you open and close your hand. During the treatment, different types of objects (with varying shapes, sizes, and weight) will be placed into your hand. You will be given a variety of instructions related to the grasping, feeling, or identifying of the object in your hand. Sometimes these instructions will be given from the investigator and sometimes from the computer. You will often be asked to grasp, or release, each of these objects as best you can. You will also be asked to concentrate on the object in your hand. An example of what you may be asked to do is to name the object. During other times, you will play games, using the robot to control game parts on the computer screen. At other times, you will move your hand so that the robot can measure your hand function.

The Action Research Arm Test is a 19 item measure divided into 4 sub-tests (grasp, grip, pinch, and gross arm movement). Performance on each item is rated on a 4-point ordinal scale ranging from: 3: Performs test normally 2: Completes test, but takes abnormally long or has great difficulty 1: Performs test partially 0: Can perform no part of test. The test is used to determine upper limb function, 0-57 points with higher is better, 57 is the highest score indicating normal arm movement.

The Arm Motor Fugl-Meyer test is an assessment of Sensorimotor Recovery After Stroke. It is a 33 item measure with 3 subgroups which are Proximal, Wrist/Hand, and Coordination/Speed. The scaling for each item works on a scale of 0-2 with 0 being not able to be done, 1 being partially done, and 2 being done normally. The scoring goes from 0-66, higher is better, 66 is considered a normal score with no noticable complications in movement.

All subjects receive the same active robotic therapy, there is no placebo arm, as a key goal of this study is to define predictors of response to active treatment.

Hand & Wrist Assisting Robotic Device: Treatment occurs in 2 hour sessions, 4 times a week over 3 weeks.

The Action Research Arm Test is a 19 item measure divided into 4 sub-tests (grasp, grip, pinch, and gross arm movement). Performance on each item is rated on a 4-point ordinal scale ranging from: 3: Performs test normally 2: Completes test, but takes abnormally long or has great difficulty 1: Performs test partially 0: Can perform no part of test. The test is used to determine upper limb function, 0-57 points with higher is better, 57 is the highest score indicating normal arm movement.

All subjects receive the same active robotic therapy, there is no placebo arm, as a key goal of this study is to define predictors of response to active treatment.