USC researchers study how brain functions when half is removed
By Michelle P. Jordan

Hemispherectomy patient Megan Howell, five, is assisted by USC doctoral student Janea Sweet.

Megan Howell is more than ready for kindergarten this fall. She can write her name, count to 50, and recite her ABCs; pretty impressive for a child who has only half a brain.

At 15 months of age, Megan underwent a hemispherectomy, a surgery in which the left half of the brain was removed in an effort to stop severe recurring seizures. Aside from a noticeable weakness on the right side of her body that hints at a problem, Megan functions nearly as well as her peers. The question is how?

How has the remaining hemisphere of her brain been able to compensate for the loss of skills, like language, normally controlled by the missing part? How can a better understanding of this process lead to more effective therapy options for future patients?

Researchers at USC's Arnold School of Public Health are striving to find out the answers to these questions by providing federally funded cutting edge rehabilitation services not offered anywhere else in the nation.

Hemispherectomy patient Megan Howell had half of her brain removed at age 15 months of age to eliminate debilitating seizures. She undergoes physical therapy during a nationally funded research project at USC. The project is headed by Dr. Stella de Bode, an assistant professor in USC's Department of Communication Sciences and Disorders, and by Dr. Stacy Fritz, a clinical assistant professor in USC's physical therapy program.

A stoke during birth left Megan Howell suffering from as many as 80 to 100 seizures daily, said her mother Shelly Howell of Topeka, Kan. Even though Megan was taking every anti-seizure medication safe for use in children, her condition continued to worsen. By 15 months old, Megan could still not walk nor talk. Her body and brain were too occupied with seizures or drugged with medication for there to be room for learning.

"She could only sit up. She was like a zombie on the medications," her mother said.

Megan began to have grand mal seizures that lasted nearly seven minutes, the point at which the brain begins to be deprived of oxygen. The parents had to make a choice: put Megan on an antiseizure drug that can be fatal, or have half her brain removed.

The Howells opted for neurosurgery, and in 2002, Megan underwent a hemispherectomy at the University of California Los Angeles. The seizures stopped immediately and have not returned. However, the difficult road was just beginning. The two primary hospitals that perform this surgery, UCLA and John Hopkins University, are unable to offer extended rehabilitation. USC is beginning to find ways to enhance the long-term rehabilitation of these patients.

Dr. Stella de Bode, a former faculty member at UCLA and current assistant professor in USC's Department of Communication Sciences and Disorders, knew Megan when her brain was whole and her body was wracked with seizures. She brought Megan and her mother to Columbia for two weeks to participate in her study, which is funded through a grant from the National Institute of Health.

De Bode and Dr. Stacy Fritz, a clinical assistant professor in USC's physical therapy program, are working together to study the brain's plasticity, its ability to reorganize and reassign neural pathways, after a hemispherectomy. The study is using two promising rehabilitation therapies: locomotor training and constraint-induced movement, to improve participants' gait and motor control. The goal is to determine which circuits in the brain help perform certain motor tasks.

De Bode said, "After the removal of one hemisphere from animals, the remaining hemisphere atrophies. We wanted to know, does this happen in humans? If so, can we reverse it with therapy?"

Their research shows the opposite occurs in humans. The hemisphere actually increases in volume overall.

De Bode said, With one hand, I do research; with the other, I help families. The families see benefits now, and research is advanced.

Megan's mom said, "If this helps Megan just the tiniest bit, then it's worth it."