The vagus nerve stimulator (VNS) is a device, somewhat like a heart pacemaker, placed in the upper chest below the left collarbone. It is connected to a wire which leads to a nerve in the neck. By stimulating this vagus nerve, the device can help reduce the number of seizures. In fact, about a third of patients experience a thirty to fifty percent reduction of seizures. Around three percent of patients actually become seizure-free.
The device stimulates automatically and periodically throughout the day and night. Patients can also learn to "turn on" the stimulator if they feel a seizure coming on, which can often stop the seizure from occurring. Because the vagus nerve affects the throat, patients may experience hoarseness or sore throat and may have difficulty speaking when using this device. Adjusting the strength of the stimulation can often address this side effect.
Vagus nerve stimulator placement requires surgical implantation under general anesthesia. Patients need multiple clinical appointments after implantation to turn the VNS on and adjust stimulation strength.