Implant Controls Epileptic Seizures
NEW YORK (Reuters) - Recent reports suggest that an implantable device can help control hard-to-treat seizures in some people with epilepsy. Approved in the United States and in Canada, the device is for seizures that can't be controlled by drugs or surgery. It is implanted in the chest and delivers an electric pulse to the vagus nerve in the neck every five minutes.
According to one study presented at the American Epilepsy Society (AES) meeting in Boston in 1997, patients implanted with a high-stimulation device had, on average, a 28% reduction in seizures. In comparison, those patients implanted with a low-stimulation version of the device had a 15% reduction in seizure frequency.
About 11% of those in the high-stimulation group had 75% or greater reduction in seizure frequency compared with 2% in the low-stimulation group, according to lead author Dr. Christopher DeGiorgio, an associate professor of neurology and neurosurgery at the University of Southern California School of Medicine in Los Angeles.
"It's not a cure-all, but it's an exciting new option to drugs or surgery," said DeGiorgio in a statement released by AES. "Additionally, it doesn't cause the typical side effects associated with drugs, and it isn't as invasive as epilepsy brain surgery."
However, the device may alter the voice, or cause cough, throat discomfort or shortness of breath. About 1%, or two patients, had vocal cord paralysis after the device was implanted, according to the study of 199 patients.
In a second study, the vagus nerve stimulator was implanted in 59 Swedish patients with seizures that had an unknown cause or those that were resistant to other treatments. About 27% of patients showed much improvement, meaning they had a 50% or greater reduction in seizures, and one patient was seizure-free. About 36% of patients had some improvement, or 25% to 50% reduction in seizures, and 24% of patients appeared to have no benefit during the time they had the implant, which ranged from 3 to 64 months. The benefit of the implant was still not clear in 12% of patients, noted the researchers from the Sahlgren University Hospital in Goteborg, Sweden.
"Vagal nerve stimulation is a safe and effective procedure for the treatment of refractory epilepsy and seems to have a broad spectrum of effects for the different epilepsy syndromes," the researchers concluded.
The vagus nerve implant is available at certain major treatment centres in Canada. Presently, the implant is not covered by provincial health plans.
Written by Theresa Tamkins