The Geodesic EEG, a useful tool

About 125,000 new cases of epilepsy are diagnosed every year.

Epilepsy is a neurological condition that produces brief disturbances in the normal electrical functions of the brain. For more than 80 years, the most effective treatment for people with epilepsy has been use of seizure-preventing medications called anticonvulsants or antiepileptic drugs.

While the medications do not cure epilepsy, they make it possible for many people to live normal lives. If the drugs are not effective, other treatment methods may be used. Surgery may be recommended for some people, or treatment with a vagal nerve stimulator that delivers electrical signals to the brain through the vagal nerve may be made available to the patient.

In order to treat an epilepsy patient with surgery, doctors must be able to pinpoint the location of the electrical disturbance causing the seizures.

"Locating where seizures begin is critical for treating epilepsy," Dr. John Miller, director of the University of Washington Regional Epilepsy Center at Harborview Medical Center in Seattle, said.
WATCH THE VIDEO

Pinpointing seizuresNew technology helps doctors pinpoint the origin of seizures.

This is important because there is a small group of patients with epilepsy who don't respond to medication.

"The idea is to do these tests, EEGs and other tests to find out where the problem is and see if that region of the brain that is causing the trouble can be removed by a neurosurgeon," Miller said.
The new Geodesic EEG (electroencephalogram) system makes it easier for physicians to pinpoint seizures. The new system is a non-invasive way to accurately locate and map seizures as they happen, thus reducing the need for surgical brain monitoring. With traditional surgical monitoring, electrodes must be placed on the brain's surface. This requires drilling into or removing areas of the skull. With the Geodesic EEG system, there is no need for this.

"It's a different kind of device that records from 256 channels, and not just on the top of the head, but also all around the head," Miller said. "The purpose of it is to define very precisely where in the brain electrical activity comes from. The idea is to record the brain waves from a person and then run a special computer program to calculate the area of the brain producing the signal."

EEG sensors are arranged in a Web-like structure and placed on the head. The trick is to monitor the patient at the time they experience a seizure. Older methods were maybe able to determine which side of the brain the seizure is coming from and possibly an approximate location of the seizure area.

"With this device, if we could capture a seizure, we can identify it, localize the seizure within a centimeter or two of where the seizure is coming from, so it's far more precise," Miller said.

The hope is doctors might be able to find out where the seizure is coming from exactly with the Geodesic EEG and skip that extra surgery where surgeons implant electrodes directly into the brain.

"Right now, we're not at the point of being able to do that. Right now, we're validating the technique and demonstrating how precise and how accurate the results are," Miller said.