The goal of this project is to develop and test a new robotic system to accommodate practice of tasks requiring reach, grasp and release of objects. Our previous work has shown that the MIME robot is safe and effective for improving reach in stroke subjects. But adequate control of hand movements is critical to a functional upper limb, and is often resistant to conventional therapeutic interventions. Many stroke survivors have residual ability to flex the fingers, but extension is often limited and impeded by increased passive stiffness in flexors, abnormal levels of increased tone in flexors and weakness in extensors. In a recent study, 38% of stroke survivors reported that impaired hand function was the most disabling motor impairment they faced.

Research Design:

We hypothesize that: 1) Gains in proximal arm function (shoulder, elbow) immediately after robotic training will be greater than after dose-matched conventional therapy; 2) Unlike in previous studies, gains in hand function immediately after robotic training will be greater than after dose-matched conventional therapy.

Methodology:

In the first year of the study, we will develop a robotic system with the ability to assist hand movement. Since many stroke survivors in the subacute and chronic recovery stages have residual ability to flex the fingers but severely limited finger extension, we will build a hand exoskeleton that can apply precise extension forces to the digits of the hand. This exoskeleton will be integrated with the ARMin III arm exoskeleton so that tasks such as arm reach, grasp of an object and release of the object can be trained. In the last 2 years of the project, we will perform a pilot clinical trial comparing this new training paradigm to dose-matched conventional therapy in chronic stroke survivors. Outcome measures will be taken before training and immediately after training.

Inclusion Criteria:

• An ischemic or hemorrhagic stroke more than 6 months prior to entry into the study;
• trace ability to move the wrist and fingers in extension;
• voluntary shoulder elevation to approximately 45 deg;
• be between the ages of 21 and 90.

Exclusion Criteria:

• Have cognitive deficits that could negatively affect their ability to complete protocols as evidenced by a score of 24 or less on the Folstein Mini - Mental State Examination (Bleeker, 1988);
• have excessive pain in any joint of the affected extremity that could limit ability to cooperate with the protocols;
• have an upper extremity injury or conditions prior to stroke that could limit participation;
• have severe hemispatial neglect.
• have a full score of 24 on the distal section of the Fugl-Myer test (FM) (Fugl-Meyer 1975); and
• have severe sensory loss.

The limited therapy hours could mask potential gains that would have been made with additional therapy. Due to the small sample size, these results need to be confirmed in a larger scale study using a parallel study design.