Removing Half of Brain Improves Young Epileptics' Lives
By ABIGAIL ZUGER
Published: August 19, 1997
BRAIN-DAMAGED children are actually able to recover some intellectual ground if the entire damaged half of the brain is surgically removed, researchers are finding.
The surgical procedure, hemi-spherectomy, was first developed in the 1920's but fell out of favor for many years because of a high complication rate. Now newer surgical techniques have made the operation safer. Its success in children with damage confined to half the brain astonishes even seasoned scientists and suggests that until now, they may have greatly underestimated the brain's flexibility, particularly in older children.
''We are awed by the apparent retention of memory and by the retention of the child's personality and sense of humor,'' Dr. Eileen P. G. Vining of Johns Hopkins University wrote in this month's issue of the journal Pediatrics.
Dr. Vining reported on the progress of 54 children who underwent hemispherectomy for recurrent, severe epileptic seizures. Most of the patients stopped having incapacitating seizures after the operation and could stop taking high doses of anti-seizure medication. Many are now in school.
The most extraordinary success of hemispherectomy was probably seen in a British boy named Alex who was born in 1980 with the left, speech-controlling, side of his brain smothered in a tangle of abnormal blood vessels, leaving him mute, half-blind, half-paralyzed and epileptic until he was 8.
Then Alex's doctors, unable to control his epilepsy with medication, removed the entire diseased left-brain hemisphere, warning his parents that although the seizures would be helped by the operation, his other problems would probably not change too much. Alex was well past the age when a mute child had ever been reported to learn to talk.
Ten months later, Alex startled everyone by suddenly speaking, first in words, then, a few months later, in complete sentences. At the age of 11 he was still pronouncing some words incorrectly ''like a well-spoken foreigner,'' but now, at 16, he is extremely fluent, said Dr. Faraneh Vargha-Khadem, a neuropsychologist at University College in London who has followed Alex for the last six years and reported his case in the journal Brain in January.
Alex's case has given scientists ''a new respect for the plasticity of the still-developing brain,'' said Dr. Mortimer Mishkin, a neuropsychologist at the National Institute of Mental Health in Maryland who has also studied Alex's progress.
Dr. John Freeman, the director of the Johns Hopkins Pediatric Epilepsy Center, said he was dumbfounded at the ability of children to regain speech after losing the half of the brain that is supposedly central to language processing.
''It's fascinating,'' Dr. Freeman said. ''The classic lore is that you can't change language after the age of 2 or 3.''
But Dr. Freeman's group has now removed diseased left hemispheres in more than 20 patients, including three 13-year-olds whose ability to speak transferred to the right side of the brain in much the way that Alex's did.
''Speech transfers over at least to the age of 13, and possibly even older,'' Dr. Freeman said. ''It's as if in the right hemisphere, all those words are there, but they're buried under tall grass and there aren't any pathways to get to them. And the older you are, the higher the grass is, and the harder the words are to find until the paths are formed. And memory is on both sides, too. When you take out one-half of the brain, either half, these children have not forgotten anything.''
Before hemispherectomy, Dr. Freeman said, some of the children followed at Johns Hopkins were having so many seizures that one episode blended into another in a state of continuous rhythmic jerking, despite high doses of medications that often left the children groggy.
In the eight-hour operation, as it is performed at Johns Hopkins, the brain tissue is removed a section, or lobe, at a time, said Dr. Benjamin Carson, a pediatric neurosurgeon there. The exposed surfaces of the remaining brain are insulated with a collagen-based material, and the empty space left in the skull eventually fills with cerebrospinal fluid.
After the operation, all the children had a very weak hand and arm on the side opposite the operation, blocked vision on that side and a weak leg that required a brace to walk or run. In many, however, strength and vision had already been compromised by the underlying disease, and the child actually became stronger after the operation rather than weaker.
Scientists still cannot explain why removing abnormal brain tissue may free the remaining tissue to function more normally. Getting rid of a child's seizures and taking a child off anti-seizure medications, which can be powerful sedatives, may play a major role, Dr. Freeman said.
Dr. Vargha-Khadem, who has followed more than 100 children after hemispherectomy, offered this assessment of the procedure: ''There's always a cost to brain injury. But if that brain injury occurs early, and if it is restricted to one hemisphere, and if the period of seizure disorder is not allowed to continue for too long, then the child really has got a fairly good chance to recoup a lot of the consequences of the brain damage and of the removal of the hemisphere.''
Photo: Dr. John Freeman of Johns Hopkins says epileptic children like Rorey McCormack, 14, have bounced back after half their brains are removed. (Marty Katz for The New York Times)