Mental Imagery to Reduce Motor Deficits in Stroke

Stroke is the leading cause of chronic disability in the United States, and lack of upper limb motor control is a major contributor to stroke-related disability. Physical and occupational therapy treatments are most commonly used to reduce long-term disability. Unfortunately, little scientific evidence exists to best target patients for therapy, define when such therapies should be provided, or even to identify the best therapies themselves. A recent National Institutes of Health consensus panel decided that there were only three therapeutic techniques with supporting scientific evidence, and for only one of these techniques, constraint induced therapy, was there evidence from a randomized trial.

The imagination, probably our most under-utilized health resource, can be used to remember and recreate the past, develop insight into the present, influence physical health, improve creativity and inspiration, and anticipate possible futures. All of us have, to some extent, experienced the effects of the imagination on the body. In recent years, data have suggested that mental practice can improve the performance of motor skill behaviors. These studies have generally shown that healthy volunteers who train with their minds on a specific task usually show better performance compared with a those that did not practice, although less than those who train physically.

To date, only a few small attempts to use mental practice in rehabilitation have been tried. A study in subacute stroke patients comparing the possibility and effectiveness of a program that combined imagery and physical therapy with a program of physical therapy only, showed that combining the two therapies is a clinically feasible, cost-effective addition to therapy that may improve functional outcomes more than participation in physical therapy only. Thus, mental practice in physical rehabilitation offers a potential way to improve motor recovery after damage to the brain.

One approach to improve arm function among patients with stroke is intensive repetitive task practice (RTP). This treatment can take the form of functional training alone or also include other ways encouraged within constraint induced (CI) movement therapy. Repetitive activities often used in physical or occupational therapy may also improve health related quality of life. While intense treatment, such as CI therapy, to overcome arm impairment may prove to be helpful, such therapy is expensive because it relies on one-on-one interaction between the patient and rehabilitation therapist. New therapeutic treatments to help existing therapy that offer helpful and money saving alternatives must be developed to improve arm use, and also, stroke survivors' quality of life.

While RTP and mental imagery may be promising treatments, we do not clearly understand the changes that may occur in the brain's of patients who have had a stroke following any physical rehabilitation. A few studies using positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) measures have shown the blood flow changes in the brain during physical movement following CIT. If the way in which recovery of motor function after stroke were better understood, better decisions could be made regarding the best selection of specific treatment strategies.