Vagal Nerve Stimulation One of the most exciting developments in the field of epilepsy treatment is the Vagal Nerve Stimulator (VNS).  The VNS is a device about the size of a hockey puck, which is placed in the chest in a manner similar to a pacemaker for the heart.  The surgeon then wraps its wires around the vagus nerve.  The vagus nerve is unique among nerves of the body in that its origin is in the brainstem (the lower part of the brain) but its peripheral nerve traverses a large portion of the body (neck, chest, and part of the abdomen).  Once implanted, the neurologist will program the VNS to deliver a series of stimulations to the vagus nerve at various strengths and frequencies. The VNS does not work by sensing a seizure. Instead, it works by repetitively stimulating the vagus nerve for a period of time and then by pausing for a period of time.  How this achieves an anti-epileptic effect is unknown but one theory is that the device "scrambles" some of the synchronous discharges of the brain. The VNS is also programmed with a special sequence that is activated when a magnet is swept over the device.  For patients who can sense if a seizure is about to start (the aura of a seizure), it can be useful in aborting the seizure.  For patients who cannot sense the impending seizure, it can be useful for family and caretakers to shorten the seizure and allow for faster recovery of the patient. VNS has not been shown to be a more effective treatment than any medication.  Its advantage lies in its lack of central nervous system side effects commonly caused by other AEDs (such as sedation and balance problems).  It has its own side effects of neck pain and voice change (usually transient).  When effective, it may allow for decreasing or eliminating other medications, which leads to a better quality of life for the patient and caregivers.  It also seems to shorten the duration of seizures and the recovery time after a seizure occurs (post-ictal state).  Unfortunately, VNS does not benefit everyone and there is no way to predict in advance who will benefit from its implantation.