Winter 2006

Putting Together the Puzzle of Epilepsy

Diagnosis and treatment of pediatric epilepsy are becoming an increasingly interdisciplinary endeavor. EEG monitoring is done at many hospitals and medical centers, but getting a good picture of often elusive seizure activity in the brain — and analyzing those seizure patterns correctly — can require the cooperation of pediatric neurologists, radiologists, surgeons, ophthalmologists, psychiatrists and child life specialists.

"A lot of people can do long-term monitoring with EEG equipment. But correctly interpreting those results, mapping normal and epileptic brain activity and performing successful surgery take a special collection of people," says Vincent Gibbons, M.D., a pediatric neurologist at UCSF Benioff Children's Hospital and the UCSF Epilepsy Center.

At UCSF's comprehensive, level IV epilepsy program, neurologists will typically monitor intensively over a three- to five-day period with video and electroencephalogram (EEG). The monitoring at UCSF Children's Hospital, unlike that at many medical centers, is done in a pediatric environment with the involvement of pediatric specialist physicians, pediatric nurses and family life specialists.

Other pediatric specialists are an important part of the team. What seems to be epilepsy may in fact be one of many other disorders, Gibbons says. "A child may have heart rhythm problems, psychosocial stress, dystonia. We sometimes will take a look at the big picture and find out the problem is not epilepsy at all," he says.

The availability of pediatric psychiatrists also is important. Gibbons points out that kids who do have epilepsy are at higher risk for comorbid conditions like obsessive-compulsive disorder, anxiety disorders or depression.

Most cases of pediatric epilepsy can be controlled with medication, but intractable seizures often require surgery. "We are recognizing that more kids with intractable seizures can have better control of their seizures with surgery," Gibbons says.

Successful surgery begins with exact localization of the epileptogenic tissues and functional mapping of healthy tissues. UCSF has the equipment and experience to provide a wide variety of brain imaging technology, some of which is available to few other medical centers in the United States.

In addition to EEG mapping, the neuroradiologists at UCSF can use high-resolution magnetic resonance imaging methods such as diffusion tensor imaging, which provides a more detailed picture of white matter, as well as cortical structures.

UCSF also has one of the few clinical, state-of-the-art, high-resolution magnetoencephalography (MEG) machines in the region. MEG monitors the subtle magnetic fields produced by the ions that flow in and out of active neurons. When the MEG data are subjected to advanced signal processing methods and combined with structural information provided by magnetic resonance (MR) imaging, the result is called magnetic source imaging.

MEG can provide more accurate activity maps than EEG monitoring because the signals are not diminished as much by the skull and other tissues surrounding the brain.

"For kids, MEG is a great technology because there are no loud, scary sounds, like in an MRI machine, and it sits atop the head more like a helmet than something they have to lie completely inside," says UCSF scientist and bioengineer Sri Nagarajan, Ph.D. "We work to sleep-deprive the kids, so that they often fall asleep during the scan."

Ultimately, epileptogenic and normal tissue may need to be mapped accurately through surgery. UCSF researchers are longstanding experts on brain mapping, both during surgery and over a longer period in special environments where indwelling brain electrodes can record electrical activity.

A highly detailed picture of brain activity is provided by electrocorticography (ECoG), in which a grid of electrodes is placed over the brain and monitored for up to a week. This information often forms the basis for the planning that surgeons must do to ensure that they are taking the epileptogenic tissue and sparing essential brain tissues.

"EEG, MEG and MR imaging are all noninvasive techniques that can help guide surgeons as they probe various areas during brain mapping, which one day will hopefully replace electrocorticography as the gold standard" for understanding the brain at work, Nagarajan says.

For more information, contact Dr. Vincent Gibbons at (415) 353-2437.

Related Information

News Releases

Vaccine for Brain Tumor Promising in Study
A vaccine for treating a recurrent brain cancer, called glioma, has shown promising preliminary results in a clinical trial at UCSF Medical Center.