Vagus nerve stimulation (VNS Therapy™) was initially approved in the U.S. for the treatment of refractory partial epilepsy that does not respond to surgery or for people who are not surgical candidates. In Europe, it has also been approved for the treatment of generalized seizures that do not respond to medications. It is widely used in the USA for this as well. VNS Therapy has been an important option for treating children and adults with Lennox-Gastaut syndrome, since this disorder may consist of both generalized and partial seizures that are usually not responsive to medications.
When should vagus nerve stimulation be considered in LGS?
Vagus nerve stimulation is a therapy that provides electrical stimulation to the vagus nerve, which is one of the major nerves going to and from the brain. Placing this device requires a short surgery, usually 1-2 hours that can be done on an outpatient basis. It does not require open brain surgery. A generator is placed under the skin on the left side of the chest. An electrode is placed under the skin that is attached to the generator at one end and the vagus nerve in the neck on the other end.
Non-medicine therapies are usually considered in any person whose seizures have not responded to the first two seizure medications tried. Since LGS has mixed types of seizures, usually more than one drug will be used at the same time before considering other treatments.
How helpful is VNS in people with LGS?
VNS Therapy for children with LGS has shown a decrease in seizures up to 58% by 6 months after the surgery. A review of 552 people with LGS from published studies and a database registry of patients with VNS, 55% of patients had seizures improve by over 50% 18 months after the VNS was placed. These numbers were similar for people who had surgery before VNS and those who did not. Drs. Kossoff and Shields summarized other studies of VNS in people with LGS and what is known about its effect on different seizure types and quality of life. An interesting aspect of VNS is that results tend to improve over time, which is the opposite of what may be seen with seizure medications.
Like other treatments, if seizure control can be improved, a person’s alertness, cognition and quality of life may improve as well. Vagus nerve stimulation may also affect mood and behavior and has been approved to treat difficult to control depression in people without epilepsy. Studies on the effect of VNS on mood and behavior in people with LGS are lacking, due to the many diverse problems that may be seen in LGS.