Patients Benefit From University Of Florida Epilepsy Research Leading To FDA Approval Of Vagus Nerve Stimulator

GAINESVILLE, Fla.---The road to independence has been a long one for Carolyn Short.

The 43-year-old Palm Springs resident now pilots a 1997 light green Saturn, but for years she relied on others to transport her around town, because the epileptic seizures that wracked her body daily prevented her from driving herself.

Her freedom came in the form of a small pacemaker-like device known as the vagus nerve stimulator, which just last month received federal Food and Drug Administration approval.

The stimulator interrupts epileptic seizures by sending an electrical stimulus to the brain and is used to treat patients who aren't helped by anticonvulsant medications.

Researchers at the University of Florida and Gainesville Veterans Affairs Medical Center were among the first to study the device in patients at Shands Hospital at UF and at the VAMC, tracking its effectiveness and safety since 1989. In many patients, the number of seizures has decreased with the treatment, says Dr. Basim Uthman, a neurologist at the UF Brain Institute and Gainesville's Veterans Affairs Medical Center.

Other patients may have significant reductions in both the intensity and duration of seizures, and report the vagus nerve stimulator helps them "snap out" of a seizure faster, Uthman said.

Short had small seizures from the time she was a baby, but when she entered her 20s she started having up to 15 convulsions a day -- many of them classified as grand mal, which caused her to lose consciousness.

"My life changed because I had to be dependent on people. I always hated asking for rides," Short recalled. "I didn't have my parents take me a lot of places because I didn't want to bother them."

In 1990 she received the vagus stimulator. The device, about the size of a stopwatch, is inserted through a small incision under the skin of the chest and is programmed to emit timed electrical impulses through wires that tunnel to the left side of the neck, then spiral around the vagus nerve. The operation takes up to two hours and is done on an outpatient basis, said Uthman, associate chief of the VAMC neurology service, director of the VAMC's clinical neurophysiology lab and associate professor of neurology at UF.

"Right away my seizures weren't as severe as before, they stopped faster and I felt better afterward," Short said.

During the first several years after Short received the implant, physicians adjusted how frequently the device fired and switched her medication. She has now been seizure-free for more than two years.

Called the "wandering nerve," the vagus is the longest of 12 cranial nerves and sends messages to many organs, including the heart, lung and stomach. This nerve also communicates with a portion of the brain stem linked to regions thought to be involved in certain epileptic seizures.

Vagus nerve stimulation appears to work by calming "hyperexcited" nerve cells and reverting brain activity to its normal pattern. It also may enhance the release of chemical building blocks that bolster cellular membranes in the central nervous system, adding stability to neurons and making them less excitable.

Because seizures occur unpredictably, physicians program the device to fire every few minutes and hope the impulses will hit just as a seizure starts. The impulses also may interfere with some events that lead to a seizure and thus prevent it from happening. Patients also can trigger the device with a magnet if they sense a seizure is imminent.

Patients with the implants, who remain on antiseizure medications, may notice their voice vibrate or detect a mild tingling in their necks during stimulation. They also may cough during stimulation for a short time after they first receive the implant.

The Epilepsy Foundation of America estimates about 2.5 million Americans have epilepsy. Of the nearly 150,000 people who develop the disorder each year, at least 10 to 20 percent suffer from uncontrolled seizures. Epilepsy is the world's second-most-prevalent neurological disorder, affecting an estimated 50 million people worldwide.

Sherry Douglas, a 33-year-old substitute teacher from Live Oak, also has benefited from the device. Douglas had up to 10 seizures a month, some very strong.

Since receiving the stimulator, she is down to two or three a month and has cut back on her medications.

"I no longer have grand mal seizures and the seizures I do have are shorter and not as intense," said Douglas, whose epilepsy stems from a head injury she suffered while falling out of a bed when she was a baby. "So even though I know I might have a seizure I don't have that fear like I used to if I feel one coming on.

"I'm on a lot less medicine and that was my goal," she added. "I'm real sensitive to medications -- they would make me sleepy and weak. The vagal stimulator doesn't have any side effects like that."

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