Vagal Nerve Stimulation Effects on Generalized-Partial Seizures and Medication in Adult Drug- Resistant Epilepsy Patients

[Results of vagus nerve stimulator implantation in children and adolescents with treatment-refractory epilepsy]

Vagus nerve stimulation (VNS) is a therapeutic procedure that can be applied in a palliative setting in patients with treatment-refractory epilepsy who are not suitable for epilepsy surgery. The mechanism of action of VNS is currently not completely understood but appears to depend on a modification of neurotransmitter metabolism. Data of 25 patients with treatment-refractory epilepsy who underwent implantation of a vagus nerve stimulator were retrospectively analyzed in a monocentric study. A reduction in epileptic seizure rate of 28% was observed 3 months after initial activation and of 32.9% after 6-12 months. The responder rate (reduction in seizure rate of more than 50% compared to before implantation) was 40% 6-12 months after initial activation. In one third of patients, a reduction in epileptic seizure rate of at least 75% occurred. Adverse effects of surgery or the stimulation were rare.

Research progress of vagus nerve stimulation in the treatment of epilepsy

The International League Against Epilepsy (ILAE) defined drug-resistant epilepsy (DRE) that epilepsy seizure symptoms cannot be controlled with two well-tolerated and appropriately chosen antiepileptic drugs, whether they are given as monotherapy or in combination. According to the WHO reports, there is about 30%-40% of epilepsy patients belong to DRE. These patients need some treatments other than drugs, such as epilepsy surgery, and neuromodulation treatment. Traditional surgical approaches may be limited by the patient's clinical status, pathological tissue location, or overall prognosis. Thus, neuromodulation is an alternative choice to control their symptoms. Vagus nerve stimulation (VNS) is one of the neuromodulation methods clinically, which have been approved by the Food and Drug Administration (FDA). In this review, we systematically describe the clinical application, clinical effects, possible antiepileptic mechanisms, and future research directions of VNS for epilepsy.