The computerized implant ``turns on'' every five minutes to deliver a 30-second burst of electricity to the vagus nerve, a pathway that carries the low-voltage current to the brain. For some patients, this has the mysterious effect of reducing the frequency and even the severity of seizures.
Years of struggle against this unpredictable disease have taught Farver, 27, not to hope for a cure. She would be happy with fewer seizures - episodes of jumbled speech, partial paralysis and fall-to-the-floor blackouts that have turned her life into a frustrating and even dangerous adventure.
``Right now, all I can tell you is that it looks promising,'' Farver said.
Epilepsy, which afflicts 2.5 million Americans, is a disease marked by bursts of abnormal electrical activity in the brain. Patients may lose consciousness or remain awake but lapse into states of fuzzy, disorganized thinking.
Farver, who lives in Westminster, Md., said she had not had a full-blown seizure since getting the implant. And twice, when she felt the strange ``auras'' that typically mean trouble, she successfully headed off seizures by holding a magnet to the pocket of skin that hides the implant.
This automatically triggers the device, advancing its cycle so it launches a pulse right away.
Like most patients, Farver says the main side effect is a mild tingling in her throat that occurs whenever the device is supplying current. This makes her hoarse and raises the pitch of her voice - side effects she is willing to tolerate if the stimulator calms her epilepsy.
It will be months before Farver and her doctors can say whether the implant has made a difference. Her seizures do not come with regularity - several weeks of peace can give way to stretches in which the attacks are frequent.
Doctors also warn of a placebo effect, a feeling of well-being that can happen when patients want something to work.
