The efficacy of vagus nerve stimulation for epilepsy in Malaysia

INTRODUCTION: The first vagus nerve stimulation (VNS) implantation in Malaysia was back in 2000, and the implantation rate increased tremendously since 2019. VNS has been used in patients who had persistent seizures despite epilepsy surgeries or were not candidates for epilepsy surgeries. We aimed to study the efficacy of VNS in Malaysia.

MATERIALS AND METHODS: We conducted a retrospective cross-sectional study on the VNS done in Malaysia. We included DRE patients from all age groups who underwent VNS from 1st January 2000 to 31st December 2022. We analysed the efficacy of VNS for patients with at least one year of implantation.

RESULTS: A total of 62 implantations were performed from 2000 to 2022. Most patients (52.5%) had implantation at <18 years old, 54.0% had focal seizures, 34.4% had Lennox Gastaut Syndrome and 23.0% had developmental epileptic encephalopathy. A total of 22.6%, 42.8%, and 63.3% of patients achieve ≥ 50% seizure reduction at three months, six months, and one-year post-implantation, respectively. At their last follow-up, 73.5% of patients had ≥ 50% seizure reduction. The majority of responders were at a current intensity of ≥ 2mA (98.0%) and 81.6% were at a duty cycle of ≥35%. No significant difference was found between responders and non-responders by age at implantation, duration of epilepsy, and seizure type.

CONCLUSION: VNS is effective for patients with refractory epilepsy in Malaysia with two-third achieving more than 50% seizure reduction at one year and the last follow-up.