VNS involves the surgical implantation of a stimulator device – similar to implanting a pace-maker.
It is a device that is implanted in the upper chest, and it regularly sends out electrical signals to the vagus nerve and brain. The VNS is often used when a child has multiple or widespread sources of seizures and is not a candidate for epilepsy surgery.
By stimulating the vagus nerve, the VNS can help reduce the number and severity of seizures. About one third of people experience a 30 to 50 percent reduction in the number of seizures. Many people also experience a marked reduction in the severity of each seizure. Less than 10 percent of children become seizure free. Also, the response to the VNS is not immediate and it can take months to show its full effectiveness.
Other benefits include improvement in mood, alertness and overall quality of life, even if seizures aren’t significantly improved. VNS has not shown any effect on cognition, but has shown positive effects on behaviour.