Vagus nerve stimulation is safe and effective in paediatric patients with drug-resistant epilepsy over the long term, with best outcomes associated with focal epilepsy, early implementation and higher stimulation parameters, a study reveals.

Researchers conducted a retrospective review of 400 paediatric patients with a diagnosis of drug-resistant epilepsy established through EEG monitoring, who underwent implantation of a vagus nerve stimulator to treat refractory seizures.

Patients (54% male; median age at seizure onset 1.04 years and median age at implantation 8.66 years) were from a single centre in the US and considered ineligible for resective epilepsy surgery.

Of them, 31% had generalised epilepsy, 29% had focal epilepsy and 40% had combined focal and generalised epilepsy, of whom 32% had Lennox–Gastaut syndrome.

They were followed for an average of 4.9 years.

Findings published in Epilepsia [link here] demonstrated that seizure frequency improved progressively, with a 90.5% responder rate achieved with vagus nerve stimulation at last follow-up, and 20.5% achieved seizure freedom.

Subgroup analysis revealed responder rates of 88.6% for generalised epilepsy, 93.1% for focal epilepsy, and 90% for combined focal and generalised epilepsy, with the highest rate of seizure freedom also observed for focal epilepsy (31.6%).

Assistant Professor Lalit Bansal.

The researchers, led by US neurologist Assistant Professor Lalit Bansal from the University of Missouri-­ Kansas City, also identified that patients who received vagus nerve stimulation within two years of seizure onset experienced significantly greater responder rates, while higher vagus nerve stimulation parameters, particularly ultra-rapid duty cycle, correlated with greater seizure reduction.

Notably, eight of the 82 seizure-free patients were able to discontinue all antiseizure medications. The mean number of drugs prior to intervention was three.

Family-reported outcomes indicated quality-of-life improvements in 90% of patients, including attention, developmental gain and academic performance. This reinforced the multifaceted benefits of the therapy, the researchers said.

Regarding side effects, the most common was obstructive sleep apnoea, which was observed in 17% of patients with 5% considered severe.

The researchers suggested systematic pre- and post-implantation screening for sleep apnoea, given its relatively high prevalence and potential clinical impact.

Less common minor side effects included pain at the incision site, throat irritation, breathing difficulties, voice change, transient cough, trouble swallowing, vocal cord paralysis, dysautonomia and side effects related to magnet use.

“This study provides compelling evidence supporting the efficacy and safety of vagus nerve stimulation therapy in paediatric patients with drug-resistant epilepsy,” the researchers said.

“The progressive increase in responder rates, reaching 90.5% at the last follow-­up, highlights the importance of optimising stimulation parameters through timely and aggressive titration strategies.”

They added that further research into individualised titration protocols and standardised treatment approaches might help maximise therapeutic potential.

Limitations included the lack of information on patients changing or adjusting their antiseizure medications, which was potentially a significant confounding factor.