With next step, Giffords has long fight ahead
Friday, January 21, 2011
With the expected transfer Friday of Rep. Gabrielle Giffords (D-Ariz.) from a hospital in Tucson to a rehabilitation center in Houston, her treatment transitions from a heroic, high-tech fight to save her life to a long and arduous slog to help her brain rebuild itself.
The success of this second effort will depend on the extent of her brain damage (which is not yet fully determined), the skill of her therapists, personal effort and the unpredictable capacity of her brain to change.
Despite the use of terms like "miraculous" to describe Giffords's progress, numerous experts describe her survival and apparently good condition as an increasingly common outcome in brain-injured patients, thanks to aggressive surgery and meticulous care afterward.
The ability of the brain to compensate for damage by at least partly rewiring itself and assigning new tasks to undamaged regions is known as "neuroplasticity." It's one of the hottest topics in biology and an important one in medicine.
Because of insights from functional magnetic resonance imaging and other technologies, scientists now realize that brain reorganization after injury is far more common and extensive than previously thought. They also know that neuroplasticity depends to a great degree on experience - which is to say, what the brain is forced to do in the critical weeks and months after it is injured.
"There is a relationship between the amount of therapy you receive and the degree of recovery," said Maurizio Corbetta, a neurologist who runs a brain injury unit at the Rehabilitation Institute of St. Louis at Washington University. "This is particularly true in the first three to six months when the brain is reorganizing."
The most common cause of brain damage is not trauma but stroke (also the fourth-leading cause of death). Of the 3 million stroke survivors alive, 40 percent have persistent weakness and disability. Brains damaged by trauma rather than stroke seem to have more capacity to recover.
"One of the things about traumatic brain injury is that recovery can go on for an extended period of time," said Michael R. Yochelson, a neurologist at National Rehabilitation Hospital in Washington. "We leave the book open."
In Giffords's favor is the report that half of her brain - the right hemisphere - was spared major damage by the bullet that passed through her head, front to back, in the Jan. 8 shooting in Tucson. That surgeons quickly removed a piece of skull to relieve swelling and pressure almost certainly spared her further damage. Her intelligence and relative youth will help, too.
Use of muscles, especially those in the limbs, will be hardest to get back if the bullet destroyed the brain cells that control them or the bundles of nerve fibers that come out of them. The recovery of language is highly variable and can occur over years. Also amenable to rehabilitation are abstract thought, memory and emotion.
Two facts about brain anatomy help explain what may go on in Giffords's brain during the months of rehabilitation.
The first is that location matters in the brain, which is like a continent of regions, states, cities and neighborhoods. Hearing, smell and memory formation all have their own locations, different from where sexual arousal, hand movement and sight reside.