Success of Radical Surgery Deepens Neurological Puzzle
With their daughter Beth about to undergo the surgical removal of half her brain, Brian and Kathy Usher found their minds returning, again and again, to the same disturbing question.
“We kept wondering,” Kathy says. “How can you take out half a brain and still have a whole person?”
It’s a question that Dr. John Freeman, chief of pediatric neurology at Johns Hopkins Hospital, hears often. “People think all intelligence resides in the brain, and therefore that if you take out half the brain, the patient ought to be half as intelligent.”
Yet, in the six months since Beth underwent the hemispherectomy to stop unrelenting seizures that were destroying the left side of her brain, the Ushers have watched her verbal skills soar from their preoperative level.
Beth marked her 8th birthday in June missing one-half of her brain but none of its byproducts--humor, personality, imagination and spirit.
Not a Perfect Correlation
“The personality does not perfectly correlate with the brain. You can have severe alteration of tissue and still have normal development,” says Dr. Jason Brandt, a neuropsychologist at Johns Hopkins.
Clearly, the whole is greater than the sum of its parts.
Beth is among eight young hemispherectomy patients and their families who are spending a sun-splashed Saturday eating fried chicken at a celebratory picnic on the Johns Hopkins University campus.
They are back in Baltimore for four days of testing at the Children’s Center of Johns Hopkins Hospital, where their heroic operations were performed. This is the first of many planned reunions of these medical pioneers, whose test results may add to researchers’ knowledge not only of rare neurological disorders, but of the workings of healthy brains as well.
Brandt is among those studying the functional consequences of having a hemisphere removed, a procedure he likens to suffering a massive stroke on one side of the brain.
Subtle Deficits
“Adults who have massive strokes in one hemisphere have profound deficits,” Brandt says. “But kids who have them often have none. There are subtle deficits in children, but they tend to be short-lived. As the brain recovers, there should be a re-establishing of normal functioning. Many hemispherectomy patients in later years can expect to attend college.”
The outlook for hemispherectomy patients hasn’t always been hopeful.
Dramatic improvements in diagnostic equipment, patient selection and surgical techniques are among the reasons for the recent success of an operation first devised at Johns Hopkins in 1928.
Dr. Walter Dandy, one of the fathers of neurosurgery, envisioned hemispherectomy as a treatment for malignant brain tumors. “Not only did it not cure them, but there was great mortality and morbidity associated with it,” says Dr. Ben Carson, head of pediatric neurosurgery and the chief surgeon for most of the recent hemispherectomies done at Johns Hopkins.
Two Earlier Comebacks
Hemispherectomy made two earlier comebacks, during the ‘40s and again during the ‘60s, as a treatment for seizure disorders. Each time, it fell into disfavor because of its common postoperative complications--bleeding and hydrocephalus, the buildup of fluid within the brain.
During the ‘70s, better anti-convulsant drugs helped limit the need for radical surgery in some seizure-disorder patients. Lumbar punctures and shunts, drainage tubes that are surgically inserted into the brain, contributed to a higher success rate for hemispherectomies done during the past several years.
Dr. Freeman says the recent surgeries have shown that removal of the damaged hemisphere, done early, can help prevent further deterioration.
Just as seizure disorders affecting one side of the brain are rare, so hemispherectomy is likely to remain a relatively rare procedure, says Freeman.
At the same time: “There are children out there in other places--good places--that are unwilling or unable to operate on them. We want to let people know that this spectacular surgery can be done.”
Youth Is Advantage
For such patients, timeliness is essential. Surgery at an early age can help take advantage of the developing brain’s superior plasticity, the ability of certain neurological functions to migrate to the opposite hemisphere.
The notion that each hemisphere has its own special abilities is relatively new, dating only to the late 19th Century.
Early dissections of the human brain, carried out in Italian medical schools more than 600 years ago, revealed a bicameral, grapefruit-sized mass with the consistency of a ripe avocado.
To 14th-Century eyes, the two halves appeared as mirror images, giving rise to the theory that nature had provided a convenient spare, as with kidneys, lungs, eyes, arms and legs.
By now the idea that the two cerebral hemispheres are identical in function as well as in form is widely discounted, although 20th-Century research suggests that the brain’s division of labor may not be as neatly compartmentalized as pop psychology would have us believe.
Boundaries Debated
Still, most scientists agree that in most people, the left side excels at symbolic representation, such as language and math, while the right brain concerns itself with direct, non-symbolic perceptions--the tricky visual task of distinguishing between similar faces, for example.
Debate over the brain’s precise boundaries rages on. Today’s evolving locator map of neurological function places scientific skills and reasoning abilities on the left side, imagination and artistic tendencies on the right.
One aspect of the “mirror image” theory has held up: The left hemisphere controls the movements and visual field on the right side of the body, while the right hemisphere is in charge of movements and sight on the left. The reason for the crossover remains among the brain’s mysteries.
Some neurological functions--vision, for one--cannot transfer from one hemisphere to the other. All of the “hemis” will remain blind in half of each eye. They also will continue to have some degree of paralysis on one side of their bodies--the side opposite the removed hemisphere.
“You lose fine motor movement in your fingers, meaning they will probably not be able to pick up small objects, like peas, with one hand,” says Carson.
And while each patient is still undergoing physical therapy, doctors predict they will probably continue to walk with at least a slight limp.
Their remaining hemispheres have proven remarkably plastic. The most significant finding, to Brandt, has been “the ability of language to come back, to persevere through it all. In a child with left seizures, after a period of time, language comes back. It’s obvious that verbal skills take precedence in the brain. In a verbal society, this is a very good thing.”
The ability of speech to transfer from the left hemisphere to the right is largely dependent upon age. “The literature says it will happen up to age 2, but the general belief is up to age 5, 6 or 7,” Freeman says.
Denise Baca of Albuquerque, N.M., was 12 when she underwent a left hemispherectomy a year ago. A former cheerleader and straight-A student, Denise had been in and out of intensive care units for two years when she arrived at Johns Hopkins by air ambulance with a tracheotomy tube in her throat. She was unconscious and hooked to a respirator. She hadn’t spoken in months.
“After much discussion, we said maybe it’s better to operate with the expectation that she would never talk again and be paralyzed on one side,” Freeman says. “Our feeling was that it was the right thing to do--an ethical approach to an impossible situation.”
Not everyone at Johns Hopkins agreed. Surgery took place, Freeman says, “over the very strong objection of senior members of the staff.”
Today, a visitor to Denise’s Baltimore hotel room finds a pretty, dark-eyed teen-ager in turquoise shorts and running shoes.
While she remains in a wheelchair, she is learning to walk with the aid of parallel bars. Her intellect is normal. Best of all, Denise is starting to talk again, although she is suffering from “anomia,” a common side effect of left-hemisphere damage.
“Shown a picture of a chair, Denise might say, ‘sitting in it.’ If we show her a picture of a bell, she might say, ‘ringing it.’ As soon as you say the word ‘chair’ or ‘bell,’ she immediately recognizes it as the word she was searching for,” Brandt says. “Anomia is a retrieval problem. The thesaurus is there, but there’s no index. She can’t access the verbal labels.”
Denise’s anomia should lessen or disappear with time, he says.
Recently, Denise suffered what may have been mild seizures emanating from the right side of her brain; while her doctors aren’t certain, they say the spells have been brought under control by anti-convulsant medicine.
The last year, says her mother, “has been great. She’s at a school for the handicapped, her math is starting to come back, and she’s beginning to carry on conversations. She laughs, she can be with us. We’ve even gone camping.”
Kathy Usher finds Beth “a little quieter, a little more cautious. But she’s getting stronger every day. In terms of both mind and her spirit, she’s definitely herself.”
Parents of hemispherectomy patients report no dramatic changes in personality following surgery, with one exception: The children are happier. They’re also enjoying markedly improved function.
“In addition to having had radical surgery, their seizures have stopped, they’re resuming normal development and they’re off medication,” says Brandt. “It’s impossible to say which of these occurrences would be responsible.”
Brandt predicts that any deficits, should they occur at all, will most likely show up in spatial relations. That means some right-hemispherectomy patients may have a tougher-than-average time reading maps, drawing or copying three-dimensional objects.
They may have some trouble perceiving subtle differences in facial features, another right-brain function. And some may suffer a slight loss of initiative or spontaneity. But any such symptoms are likely to lessen or disappear with time.
