Vagus nerve stimulation (VNS) may be considered for seizures in children, for seizures associated with Lennox-Gastaut syndrome (LGS), and for improving mood in adults with epilepsy, according to an evidence-based guideline update from the American Academy of Neurology (AAN).
The update also notes that VNS may have improved efficacy over time. It further recommends that children be carefully monitored for site infection after VNS implantation.
The updated guideline was published online August 28 inNeurology.
New Data Fuel Update
In 1997, the US Food and Drug Administration (FDA) approved VNS as adjunctive therapy for reducing the frequency of seizures in patients older than 12 years with partial-onset seizures refractory to antiepileptic medications.
In 1999, a Therapeutics and Technology Assessment Subcommittee of the AAN concluded that VNS is indicated for patients over age 12 with medically intractable partial seizures who are not candidates for potentially curative surgical resections, such as lesionectomies or mesial temporal lobectomies. The subcommittee also recommended that patients undergo a thorough epilepsy evaluation to rule out nonepileptic conditions or treatable symptomatic epilepsies before VNS implantation.
At that time, evidence was insufficient to recommend VNS for epilepsy in young children or for LGS-associated seizures, George L. Morris III, MD, from the Aurora Epilepsy Center, St. Luke’s Medical Center, Milwaukee, Wisconsin, and the guideline panel explain.
Since the 1999 AAN assessment, the FDA also approved VNS for the adjunctive long-term treatment of chronic or recurrent depression in patients older than 18 years with a major depressive episode not adequately relieved by 4 or more antidepressant treatments. Moreover, there are new reports of long-term efficacy and VNS use in pediatric epilepsy and other seizure types and syndromes, the panel points out.
The guideline update takes into account relevant studies published since 1999 on the efficacy and safety of VNS for epilepsy. Among the key findings and recommendations:
- VNS was associated with a greater than 50% reduction in seizure frequency in 55% (95% confidence interval [CI], 50% – 59%) of 470 children with partial or generalized epilepsy (13 class III studies). VNS “may be considered as adjunctive treatment” in this setting (level C), the guideline states.
- VNS was associated with a greater than 50% seizure reduction in 55% (95% CI, 46% – 64%) of 113 patients with LGS (4 class III studies). VNS “may be considered” in patients with LGS (level C), the guideline says.
- VNS was associated with an increase in at least 50% seizure frequency reduction rates of roughly 7% from 1 to 5 years after device implantation (2 class III studies). VNS “may be considered progressively in patients over multiple years of exposure” (level C).
- >VNS was associated with significant improvement in standard mood scales in 31 adults with epilepsy (2 class III studies). “In adult patients receiving VNS for epilepsy, improvement in mood may be an additional benefit” (level C), the guideline says.
- There is evidence of an increase in infection risk at the VNS implantation site in children relative to that in adults (odds ratio, 3.4; 95% CI, 1.0 – 11.2). “Extra vigilance in monitoring for occurrence of site infection in children should be undertaken,” the guideline says.
- VNS may have improved efficacy over time.
Recommendations for Future Research
The panel concludes that more information is needed on the treatment of primary generalized epilepsy in adults. They found only 1 class II article addressing this population.
They also point to a need to study the effectiveness of VNS in epilepsies other than those discussed in the update, such as primary generalized syndromes. “Some reports have discussed VNS use in small numbers of patients with juvenile myoclonic epilepsy (JME); larger reports would help substantiate whether VNS is appropriate in medically refractory JME,” they write.
They also say more information about parameter settings (eg, cycle time length) would “potentially help with better VNS management and use.” They recommend developing techniques to reduce infection risk at the VNS site in children and note that more information is needed on the effects of VNS on sleep apnea.
The guideline was developed with financial support from the American Academy of Neurology. None of the authors received reimbursement, honoraria, or stipends for their participation in development of the guideline.