Sunday, June 01, 2008

Can a brain pacemaker control seizures effectively?

Tony Mendoza fractured his ribs and mangled his nose after he had an epileptic seizure and fell down a flight of stairs.

Sydney Pershing often cried in her room because of the depression resulting from her epilepsy, a neurological condition characterized by recurrent seizures, usually of unknown cause.

Those episodes occurred before Mendoza, 40, and Pershing, 30, heard about Vagus Nerve Stimulation therapy, in which a surgically implanted device sends mild electrical pulses to the brain to prevent electrical irregularities that cause seizures.

The therapy, which costs about $25,000 and is covered by most insurance companies and Medicare, is used in conjunction with medication. The Food and Drug Administration approved it in 1997 for epilepsy that cannot be controlled with anticonvulsant medication, which involves about about 30 percent of the 2.7 million cases in the United States.

Seeing success in treating epilepsy patients, the device's manufacturer, Cyberonics, petitioned the FDA to expand its use to cover the most severe form of depression.

The FDA approved it in 2005, but the decision was controversial. The agency initially overrode its advisory panel and withheld its approval, after reviewing studies and petitions questioning whether the device worked for depression. Medicare and most major insurance companies don't cover it, calling the treatment for depression experimental.

Karen Riley from the FDA said Friday in an e-mail that the device ``is intended for people with chronic or recurrent depression who are experiencing a major depressive episode and have not had an adequate response to four or more adequate antidepressant treatments. FDA reviewed the data and decided to approve the device to provide an alternative for this narrow patient population.''

Despite the doubts from some, doctors and patients say the pulses to the brain appear to work in epilepsy cases.

The surgery usually lasts two hours. The battery-operated pulse generator, ''about the size of an Oreo cookie,'' is placed in the chest and electrodes are placed in the neck around the vagus nerve, which originates from the brain stem, said Dr. Jose Gonzalez, medical director of the Epilepsy Foundation of Florida.

''It's like a cardiac pacemaker,'' says Dr. Eugene Ramsay, professor of neurology and psychiatry at the University of Miami's Miller School of Medicine. ``It activates the vagus nerve in the neck on the left side and sends signals to the brain stem.''

About two weeks after the surgery, a neurologist will program the device to stimulate the nerve in regular intervals. When a seizure is about to occur, there will be an electrical disturbance on some neurons in the brain. ''VNS will counteract this disturbance and . . . eliminate the possibility of a seizure,'' Gonzalez says.

Optimum results take time. It could be months or a year before the proper setting is found.


Mendoza, of Hialeah, waited about nine months before he could control his seizures. He developed epilepsy and had about three seizures a day after a softball hit him in the head when he was 10.
''They didn't let me play sports because I was having seizures,'' he says. ``At school I got no respect. . . . It was so stressful for me because I couldn't go to the prom. It really hurt. The military, the police academy, I couldn't enter it. I entered college, but it didn't go well for me.

``I was at Miami-Dade North and I had a seizure and fell off the second floor, down the stairs. When I woke up my ribs were broken in half, my nose was cracked.''

In 1997, he underwent brain surgery, which reduced his seizures by 70 percent. Although they never reached the grand mal level, which involves a loss of consciousness and violent muscle contractions, Mendoza still saw Ramsay, his neurologist, every three months. Ramsay recommended the VNS therapy.

In 1999, Mendoza had the device implanted in his chest. Afterward, ''I still had some seizures,'' he says. ``This happened for eight or nine months. Ever since then, I've had only five seizures in nine years. It's been a blessing.''

Mendoza sees Ramsay less frequently now -- once or twice a year -- and last December he started a travel business, Tony2Travel Inc. ``I'm going to Mexico in July . . . In the future I want to sky dive, scuba dive, enjoy my life.''


Side effects of the VNS therapy include a change in the patient's voice when the pulse generator activates, increased coughing, difficulty breathing and the possibility of an infection occurring around the implant. Unlike some epilepsy medications, the device poses no threat to the heart, liver or kidneys, says Ramsay, one of the first clinical investigators for VNS therapy.

The device is intended for patients 12 and older, but a study in the April 30 edition of the journal Neurosurgical Review concludes that it might be beneficial in toddlers affected by severe epilepsy and multiple developmental disabilities. On the subject of depression, another study, in the March 27 edition of Journal of Affective Disorders, concludes that despite promising results, more clinical trials are needed.

Pershing, of Coral Springs, is convinced that VNS therapy has helped with her depression as well as her seizures.

''I was terribly depressed. I cried a lot and I gained weight, but I have done a total 180-degree change,'' she says.

Pershing, a medical assistant, was diagnosed when she was 13. ''At the beginning I had just one grand mal seizure, then they were consistent, maybe four or five a month,'' she says. ``The seizures lasted five to 10 minutes, and they happened just about anywhere.''

Now, Pershing has a seizure every two months or so, and they last two to three minutes. ''When I get stressed or irritated I have a seizure, so I try not to get stressed,'' she says.

Pershing carries a VNS magnet with her at all times. The hand-held device can be swept over the implant to stop or shorten the seizure and lessen its intensity. ''Sometimes I have partial complex seizures where you stare in space.'' She'll come out of it when the magnet is slid over the stimulator.

''All my friends and family know I have the implant,'' she says. ``If you were to have a seizure in the middle of the street and no one knows, they would call 911. You don't need to go to the hospital every time you have a seizure.''


Post a Comment

<< Home