Abstracts

Rationale: The VNS (Vagus Nerve Stimulation) is a type of neuromodulation therapy used in patients with focal epilepsy, usually reserved for those who are not candidates for resective surgery. However, there is not clear evidence if it has the same effect in all types of epilepsy. Our aim is to assess how effective this treatment is in those with generalized tonic-clonic (GTC) seizures in the context of generalized epilepsy. Methods: We interrogated the database of the Epilepsy program at Western University and identified those patients with generalized epilepsy, who underwent VNS implantation, since this treatment became available in Canada, until March 2018. Results: A total of 21 patients with history of generalized epilepsy underwent VNS implantation in our center. The mean age of implantation was 27.3 years (18-51), 12 patients (57%) were male. Mean follow up was 65.2 months (5 to 192 months). Mean seizure onset was 7.5 years of age (birth-17). The number of anti seizure medications in average was 2.5 (range: 2-6), and previously ASM was 5.6 in average (2-9). The frequency of GTC seizures range from daily to several per year. After the implantation, none of the patients was GTC seizure free. Eight (39%) had 50% or more in seizure frequency reduction. Only one patient developed an infection in the area of implantation. 10 patients had side effects as neck pain or voice changes, but none of them required explantation. The average output current was 2mA, signal frequency of 30 Hz, pulse width of 500µSec, signal on 45 sec, signal off 5 min. Conclusions: VNS appears to be a therapy effective not only in focal epilepsy, but also in reducing the number of GTC seizures in those with generalized epilepsy. Funding: Not applicable