The Plasticity of the Brain: Guiding the Damaged Brain to Recover From Injury and the Healthy Brain to Improve Itself

What are the limits of rehabilitation for a person with a damaged brain, and how can persons with healthy brains improve themselves further?
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Co-authored by Gitendra Uswatte, Ph.D.
Professor of Psychology, University of Alabama at Birmingham

Before 1980, it was widely accepted as fact in neuroscience that the central nervous system is hardwired and fixed. The very strong belief was that after an injury in adults, such as stroke or traumatic brain injury, the brain cannot repair itself. However, over the last 20 to 30 years persuasive evidence has been accumulating rapidly that the brain is plastic throughout a person's lifespan; in effect, the adult brain can not only be rewired, it can also be structurally remodeled.

Another strongly held belief prior to 1990 was that after damage to the brain, recovery of impaired functions -- such as the ability to use the arms and the legs or to speak -- could occur for about one year afterwards, but beyond that further improvement was not possible. Things could get worse, but no matter what treatment was administered, function could not be improved. This belief was related to the now-overturned axiom that the adult brain is not plastic. As a result, millions of patients in this country who have deficits in movement and speech as a result of strokes or traumatic brain injuries in previous years were, and to a large extent still are, a largely untreated group.

However, we developed a treatment at UAB termed CI therapy, or constraint-induced movement therapy, that can harness the capacity of the adult brain for neuroplastic change and produce large improvements in lost movement and speech many years after the damage that produced it. Moreover, the neuroplastic changes and large improvements in function were not less for older persons than for teenagers. We have applied CI therapy successfully to patients who had a stroke 50 years earlier, and we often work in our clinic with patients in their 80s and 90s.

The Dalai Lama, who has considerable sophistication in the area of neuroscience, is very interested in the plasticity of the brain and how it relates to the reduction of human suffering. We are deeply honored that he will be visiting our laboratory and clinic at the University of Alabama at Birmingham on Saturday, October 25, for a dialogue, "Neuroplasticity and Healing." UAB will have a live webcast dialogue with him, Michael Merzenich, M.D., Taub, and Norman Doidge, Ph.D., who has written a best-selling book on neuroplasticity entitled The Brain That Changes Itself. Another book by him on this subject entitled, The Brain's Way of Healing is about to be published.

CI therapy is founded on basic research Taub carried out some time ago. It represents the application of behavioral training methods to the field of rehabilitation. CI therapy for rehabilitating the arm has four main components: 1) intensive training for three and a half hours/day for 10 or 15 consecutive weekdays, 2) training by the behavioral technique termed shaping, which is a method that assists in setting goals for a certain behavior 3) restraint of the unaffected hand in a padded mitt to induce increased use of the affected arm for a target of 90 percent of waking hours, and 4) the "transfer package" which is a set of behavioral techniques designed to induce transfer of improvement in movement achieved in the laboratory to increased spontaneous use of the affected arm in everyday activities in the life situation. The latter is actually by far the most important component of CI therapy.

The results we have seen at UAB have been replicated quantitatively in clinics whose therapists we have trained. Overall, positive results have been obtained in close to 500 published studies. In addition, CI therapy was the subject of a multisite randomized trial supported by NIH, which is generally considered to be the gold standard of evidence in medical fields.

Since our initial theoretical formulation of the mechanism of CI therapy, we have extended its application to a number of different types of injury to the central nervous system. After working with the arms of patients after stroke, we have obtained similar results in young children with cerebral palsy and patients with traumatic brain injury, multiple sclerosis, and brain resection. We have also obtained equally positive results for the legs with a modification of the basic CI therapy arm protocol in patients with stroke, traumatic brain injury, multiple sclerosis, spinal cord injury, and fractured hip. Other modifications of the basic technique have yielded positive results for speech after stroke (CI Aphasia therapy) and for focal hand dystonia in musicians.

We have found that CI therapy for the arm produces marked increases in grey matter volume in the brains of patients with stroke, cerebral palsy, and multiple sclerosis. The changes are not only in the area that normally controls movement of the treated arm, i.e., primary motor cortex in the hemisphere opposite to the arm, but also in surrounding areas and in the other hemisphere. It is as if the brain makes use of whatever resources it has available to support the improved movement of the affected arm that CI therapy requires that a patient make. One could say that the brain is engaged in repurposing brain structures in the process that Norman Doidge has called "healing itself."

One of the main conclusions we can take away from the research we have carried out at UAB is that we really do not know what the limits of rehabilitation are. Another way of saying this is that we do not really know the extent to which the plasticity of the brain can be exploited to improve function from serious impairment back to normal movement or speech, or, in effect, the extent to which the brain can heal itself. Therefore, one question we can ask is what techniques can we develop in the future to take full advantage of the brain's capacity to heal.

In a sense, there is a parallel development in the study of cognitive function in people without brain injury, partly driven by research on meditation. For example, Dr. Richard Davidson and others have demonstrated that the practice of the type of meditation espoused by the Dalai Lama, which is practiced by many people now in the United States and other countries in the West, termed mindfulness meditation, can alter the function and structure of various portions of the brain. Dr. Davidson's work was preceded by many studies showing that Transcendental Meditation strikingly alters many aspects of brain function. Given this work, we can now ask what techniques can be used to enable persons without brain damage to improve themselves. The brain data gives point to the self-report of countless individuals over the millennia that meditation is certainly one of those techniques.

These two questions will be addressed in the forthcoming dialogue with the Dalai Lama that will be held at UAB. What are the limits of rehabilitation for a person with a damaged brain, and how can persons with healthy brains improve themselves further? The answers to both questions would seem to be related in that both seem to involve the plasticity of the adult brain; that is, the ability of the brain to change itself.

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