Extension of the MIME Robotic System for Stroke Rehabilitation

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.

This scale assesses motor impairments at the shoulder, elbow, wrist and fingers (Fugl-Meyer 1975). Individual subscores are added to create a total score that ranges from 0 to 66 points. A score of 66 indicates no impairment.

This scale is a standardized assessment of functional limitations in the upper extremity. Individual subscores are summed to create a total score that ranges from 0 to 57 points. A score of 57 indicates no functional limitations.

A Motion Analysis Evaluation Will be Performed on Reach and Grasp Tasks. The Kinematics Will be Measured Using an Electromagnetic Tracker (Flock of Birds, Ascension Technology Corp., Burlington VT).

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.

Brokaw EB, Nichols D, Holley RJ, Lum PS. Robotic therapy provides a stimulus for upper limb motor recovery after stroke that is complementary to and distinct from conventional therapy. Neurorehabil Neural Repair. 2014 May;28(4):367-76. doi: 10.1177/1545968313510974. Epub 2013 Dec 2.