Vagus nerve stimulation for focal seizures

Area of Science:

• Neurology
• Neurosurgery
• Medical Devices

Background:

• Epilepsy is a chronic neurological disorder characterized by recurrent seizures.
• Drug-resistant epilepsy often requires adjunctive therapies beyond medication.
• Vagus nerve stimulation (VNS) is a neuromodulatory treatment involving electrical stimulation of the vagus nerve.

Purpose of the Study:

• To evaluate the efficacy and tolerability of Vagus nerve stimulation (VNS) as an add-on treatment for drug-resistant focal epilepsy.
• To compare the effects of high-level versus low-level VNS stimulation.
• To assess VNS impact on seizure frequency, treatment withdrawal, adverse effects, quality of life, cognition, and mood.

Main Methods:

• Systematic review and meta-analysis of randomized controlled trials (RCTs).
• Included studies compared high- vs. low-level VNS stimulation or VNS vs. no stimulation.
• Outcomes assessed included seizure reduction, treatment withdrawal, adverse events, quality of life, cognition, and mood.

Main Results:

• High-level VNS demonstrated over 1.5 times greater effectiveness in reducing seizure frequency compared to low-level VNS (moderate-certainty evidence).
• Adverse effects, including hoarseness and dyspnea, were more frequent with high-level stimulation (moderate to low-certainty evidence).
• Treatment withdrawal rates were low, suggesting good tolerability, though evidence quality varied.

Conclusions:

• Vagus nerve stimulation (VNS) is an effective and generally well-tolerated adjunctive therapy for drug-resistant focal epilepsy.
• Higher stimulation levels appear more effective in reducing seizure frequency.
• Further high-quality research is recommended to fully elucidate VNS efficacy and tolerability.