Vagus Nerve Stimulation for epilepsy in children and adults: Assessment of Longer term clinical and cost Effectiveness in a Randomised controlled Trial (VNS-ALERT)

Epilepsy is a common disorder of the brain. Over 600,000 people have epilepsy in the United Kingdom. Around two thirds of those people will respond well to medication. In the remaining third, epilepsy can have a massive impact on quality of life and reduce life expectancy. There can also be very substantial costs to people with epilepsy, their families, carers and the National Health Service. People who have epilepsy that does not respond to medication can be treated by brain surgery, but that is only possible for a minority. The area causing epilepsy cannot always be identified or removing it might cause harm. Only 50-60% of those that have such surgery are free of seizures in the longer term. Another approach is vagus nerve stimulation (VNS). This involves implanting a battery under the skin on the left side of the upper chest (like a pace maker) and placing a wire around the vagus nerve. VNS therapy has received NHS approval for drug refractory epilepsy, but there are important limitations in the evidence we have available. For example, there is very limited information on effectiveness for children or adults with complex epilepsy and intellectual disability, who represent half of those currently having VNS implanted in the NHS. The longer-term effectiveness of VNS is also unknown. Whilst there are claims that effectiveness increases over a number of years, we do not have evidence from randomized controlled trials to support this. Here, we plan to find out whether VNS does offer sustained benefit to people with drug resistant epilepsy.