Structural and Functional Brain Changes in Response to Post-Stroke Rehabilitation

A third of American Veterans is left with moderate to severe motor deficits after stroke. Intensive rehabilitation can resolve some of these deficits. Motor function restoration is associated with and dependent on reorganization of neuronal networks (i.e. plasticity). However, our understanding of human brain plasticity during functional recovery is incomplete. Furthermore, it is unknown what patterns of structural brain changes are associated with greater gains in motor function as a result of motor learning therapy. The main objective of the study is to characterize the reorganization of brain structure and function that is associated with greater gains in motor function following restorative rehabilitation for chronic survivors. This will further our understanding of recovery after brain injury and subsequently assist in more accurately directing rehabilitation therapies to produce the best possible outcomes.

The two hypotheses are: I. There is reorganization of both movement control brain regions and pathways between regions that is associated with functional motor recovery in response to intensive motor learning after stroke; and II. For stroke victims with upper extremity deficits, motor recovery is associated with changes in the sequential timing of activity across cortical regions.

Design and Methods. A cohort of chronic stroke survivors with upper extremity deficits will be treated by our intensive multimodal 12-week motor learning program. Brain imaging (functional Magnetic Resonance Imaging (fMRI) and Diffusion Tensor Imaging (DTI)) and neurophysiological (Electroencephalogram (EEG)) studies as well as functional motor tests (Arm Motor Activity test and Fugl-Meyer Coordination test) will be obtained before and after the treatment. Age-matched control subjects will be evaluated as well. DTI/fMRI and EEG/fMRI combination techniques will be used to determine changes in brain structure and function as a result of the treatments. A regression analysis will determine which brain structure parameters can predictor greater motor function gains.

Inclusion criteria

for chronic stroke patients:

• Medically stable and at least 6 months post ischemic stroke.
• Inability to use upper limb for functional tasks
• Sufficient endurance to participate in rehabilitation
• Cognition sufficiently intact to give valid informed consent to participate
• Ability to follow two stage commands
• Trace or better contraction of the following muscles: finger flexors, wrist flexors and extensors, shoulder flexors or abductors, shoulder horizontal abductors, scapular retractors
• Muscle tone of fingers, wrist and elbow flexors ≤3 (Ashworth scale)
• Age > 21

Exclusion criteria

• Acute or progressive cardiac, renal, respiratory, neurological disorders or malignancy
• Active psychiatric diagnosis or psychological condition
• Lower motor neuron damage or radiculopathy
• Hand grasp and release sufficient to grasp 4 oz. can, lift 12 inches, replace it in original position and release grasp within 1-2 seconds of the time of the unaffected extremity
• Absent position sense at elbow or wrist
• More than one ischemic strokes or stroke affecting both sides
• Metal implants, pacemaker, claustrophobia, or inability to operate the MRI patient call button