On November 14, 2013 the U.S. Food and Drug Administration (FDA) announced that it had approved a new neurostimulator device which will cut down on the number of seizures in epilepsy patients who do not do well on medications.
The new device, called an RNS Stimulator, will be implanted under the scalp and inside the skull. It is connected to either one or two electrodes which are strategically placed where it is believed that the seizures are originating from.
According to Christy Foreman, director of the Office of Device Evaluation in the FDA’s Center for Devices and Radiological Health, the neurostimulator is able to detect any abnormal electrical activity in the brain and then respond by sending electrical stimulation to the brain via the electrodes. This stimulation helps return the brain activity back to normal before a person actually experiences any seizure symptoms.
Epilepsy occurs when groups of nerve cells in the brain undergo permanent changes which make them overly excitable. They then begin firing abnormally, creating such symptoms as violent shaking, changes in consciousness or staring spells.
According to the Epilepsy Foundation, epilepsy is the third most common neurological disorder in the country, affecting almost 3 million Americans. About 40 percent of those with epilepsy, however, do not experience complete relief from their seizures, even with medication.
The FDA based its approval of the neurostimulator device on the results of a three-month-long randomized control trial including 191 patients with drug-resistant epilepsy.
After the device had been turned on and in active use for three months, the patients had almost a 38 percent reduction in their average number of seizures per month. In the comparison group, those who had an inactivated implant, the reduction in symptoms was only about 17 percent.
The median reduction in seizures, which the study authors say is more representative of what a typical patient might experience, was 34 percent for those with the active implant and 19 percent for those whose implant was not turned on.
At the upper end of the response continuum were 29 percent of the patients with active neurostimulators, who experienced at least a 50 percent reduction in their overall number of seizures. The most improvement in those with inactive neurostimulators was 27 percent.
During two years of follow up, there was a continued reduction in the frequency of seizures.
Patients who have the RNS Stimulator implanted must be aware, however, that they cannot undergo such medical procedures as diathermy, electroconvulsive therapy (ECT), magnetic resonance imaging (MRI) or transcranial magnetic stimulation (TMS). Even if the device is not turned on, the energy produced by these procedures could lead to permanent brain damage.
The most often reported side effects from the procedure were infection at the site of the implant and early depletion of the battery.
The neurostimulator is manufactured by a company called Neuropace, Inc. in Mountain View, California.
By Nancy Schimelpfening