BALTIMORE — 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.
"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.