Brainwave – The Irish Epilepsy Association – Shedding a light on epilepsy

Vagus nerve stimulation (VNS) effectively reduces seizure frequency in some patients with drug-resistant epilepsy, but VNS treatment may have to be applied for several years before any effect can be seen. This was the message from Veronica Pelliccia, MD, Department of Neuroscience, University of Pisa, Italy, who presented her findings, the results of a long-term study, which took place between 1995 and 2009 at the 9th European Congress on Epileptology (ECE) in Rhodes.

The researchers enrolled 28 patients (20 men and 8 women; mean age 47 years): 3 with generalised and 25 with partial seizures in an Italian tertiary-care epilepsy centre. All patients were implanted with VNS stimulators and were followed for up to 14 years.

The investigators found that the efficacy of VNS increased over time, and no significant adverse events occurred in any of the patients. Seizure frequency decreased by 32.5% after 1 year, 41.8% after 2 years, and 47.2% after 3 years.

Several patients showed a delayed response to VNS, with reduced seizure frequency occurring only after 2 to 3 years of treatment. Seizures were reduced by over 70% in patients with generalised epilepsy and the majority of patients with partial epilepsy responded at maximum follow-up.

According to the investigators, these results show that VNS is safe and effective over the long term, but they cautioned that VNS therapy might have to be continued for at least 3 years before it begins to reduce seizure frequency.