Robotic Training for Stroke Neurorehabilitation

The overall goal is to further develop a robotic exoskeleton for neurorehabilitation of arm function after stroke. The investigators previously developed a novel training protocol that combined the ARMin and HandSOME exoskeletons. This is one of only a few arm exoskeletons that allow coordinated whole limb training in reach and grasp tasks with both virtual and real objects. However, the robot has a very large inertia and friction, and only gross grasp patterns are available. In development work, the investigators will significantly modify the AMRin and HandSOME to deliver a state-of-the-art lightweight robotic exoskeleton capable of retraining a wide range of functional activities. In the subsequent testing phase, a clinical trial will examine the effects of robotic training in chronic stroke subjects.

In a pilot clinical trial, the investigators found that the current robotic exoskeleton elicited improvements in arm function that can potentially supplement conventional methods to improve outcomes. However, the robot has a very large inertia and friction, and only gross grasp patterns are available. Therefore, improvements in movement speed and fine grasp were limited after robotic training. In development work, the investigators will significantly modify the ARMin and HandSOME to deliver a state-of-the-art lightweight robotic exoskeleton capable of retraining a wide range of functional activities. The investigators will reduce the inertia and friction of the robot to 1/4 of current values, incorporate an adaptive algorithm to automatically adjust assistance levels and extend the range of grasp patterns to include power grasp, thumb-index finger pinch and key pinch. Using the improved device from the development activities, the investigators will perform a clinical trial to compare the effectiveness of robotic training to conventional therapy from an occupational therapist. To take advantage of the facilitatory effect of robot therapy on subsequent conventional therapy, the experimental treatment will be 12 hours of robot therapy followed by 12 hours of conventional therapy. Chronic stroke subjects (N=38) will be randomly assigned to receive this experimental treatment or 24 hours of conventional therapy from an occupational therapist.

Eligibility Criteria:
Inclusion Criteria:

* Age 21 or older
* Ischemic or hemorrhagic stroke (with confirmatory neuroimaging) that occurred more than 6 months before entering the study
* Presence of voluntary hand activity indicated by a score of at least 1 on the finger mass extension/grasp release item of the Fugl-Meyer Test of Motor Function
* Adequate cognitive status, as determined by clinical evaluation
* No upper extremity injury or conditions that limited use prior to the stroke

Exclusion Criteria:

* Cannot give informed consent
* Have clinically significant fluctuations in mental status within a month of enrollment
* Were not independent prior to the stroke as measured by scores \<95 on the Barthel Index or \>1 on the Modified Rankin Scale
* Have hemispatial neglect as determined by \>3 errors on the Star Cancellation Test
* Have severe sensory loss as determined by a score of 2 on the sensory item of the NIHSS
* Receiving oral or injected antispasticity medications during study treatment
* Pain that interferes with daily activities
* History of prior stroke