New technologic device helps control seizures

Epilepsy patients in a clinical trial who received an experimental brain treatment from Fridley-based Medtronic saw a significant reduction in seizures — a result released Saturday night that will spur the company to seek Food and Drug Administration approval so it can sell the device.
The trial was the most rigorous study thus far of Medtronic's deep brain stimulation device for epilepsy. The results were presented at the annual meeting of the American Epilepsy Society in Seattle.

They mark a significant milestone in Medtronic's drive to further develop the market for brain stimulators, which already are approved for use in patients with tremor disorders such as Parkinson's disease.

Much like pacemakers use electrical energy to regulate heart rhythms, implantable stimulators like the epilepsy device target specific portions of the brain.

"While the exact mechanism of why this works is not known, it has something to do with disrupting the highly synchronized abnormal electrical activity in the brain during a seizure," said Robert Fisher, professor of neurology and director of the Stanford Epilepsy Center, who was principal investigator of the trial.

The device consists of a pulse generator that is implanted in the chest and connected to small electrical wires that are tunneled beneath the skin and up the neck to the top of the head. The wires pass through the skull and reach deep into the brain, where they deliver electrical stimulation.

Brain stimulators are part of a group of so-called neuromodulation devices that Medtronic and rivals Boston Scientific and Little Canada-based St. Jude Medical see as key to future growth.
Houston-based Cyberonics already has approval from the FDA to sell a neuromodulation device for epilepsy patients, although that product sends electrical pulses to the vagus nerve in the neck — not the brain.

Epilepsy is a neurological condition that produces seizures affecting a variety of mental and physical functions. Seizures occur when a brief, strong surge of electrical activity affects part or all of the brain.

Patients enrolled in the study have had epilepsy for an average of 22 years, and their cases have been so severe that epilepsy medications haven't helped much.

The study found that 53 patients using the device in conjunction with epilepsy medications saw a median reduction in seizure frequency of 38 percent at three months — significantly better than the result for a control group of 55 patients who received the device but weren't receiving stimulation.
After three months, patients in the control group also had their devices turned on, and more patients saw a higher level of improvement, Fisher said. One of the key findings, he said, is that 60 percent of study participants for whom researchers had long-term data reported a 50 percent or greater reduction in their baseline rate of seizures at the end of the study period — anywhere from one to four years.

"If it hadn't been sustained, I wouldn't be so interested," Fisher said, adding that patients likely wouldn't let doctors put "wires in their heads" for a treatment that stopped working within six months. "But it turned out to be lasting."

Although Fisher said the results were "promising," he stressed that the device doesn't provide a cure for epilepsy. While a few patients in the study were seizure-free for long periods, a few saw no benefit, he said.

Others saw some level of reduction in seizures and, in some cases, a reduction in the intensity of seizures.

About 11 percent of study participants suffered an infection — not in the brain, but in the chest, neck or scalp where the pulse generator and wires were implanted.

Even if all goes well with Medtronic's forthcoming application for FDA approval, Fisher added, the treatment likely wouldn't be available until mid- to late 2010.

Christopher Snowbeck can be reached at 651-228-5479.