Vagus nerve stimulation (VNS): recent advances and future directions

Abstract

Purpose: Vagus nerve stimulation (VNS) is emerging as a unique and potent intervention, particularly within neurology and psychiatry. The clinical value of VNS continues to grow, while the development of noninvasive options promises to change a landscape that is already quickly evolving. In this review, we highlight recent progress in the field and offer readers a glimpse of the future for this bright and promising modality.

Methods: We compiled a narrative review of VNS literature using PubMed and organized the discussion by disease states with approved indications (epilepsy, depression, obesity, post-stroke motor rehabilitation, headache), followed by a section highlighting novel, exploratory areas of VNS research. In each section, we summarized the current role, recent advancements, and future directions of VNS in the treatment of each disease.

Results: The field continues to gain appreciation for the clinical potential of this modality. VNS was initially developed for treatment-resistant epilepsy, with the first depression studies following shortly thereafter. Overall, VNS has gained approval or clearance in the treatment of medication-refractory epilepsy, treatment-resistant depression, obesity, migraine/cluster headache, and post-stroke motor rehabilitation.

Conclusion: Noninvasive VNS represents an opportunity to bridge the translational gap between preclinical and clinical paradigms and may offer the same therapeutic potential as invasive VNS. Further investigation into how VNS parameters modulate behavior and biology, as well as how to translate noninvasive options into the clinical arena, are crucial next steps for researchers and clinicians studying VNS.

Keywords: Brain stimulation; Neuromodulation; VNS; Vagus nerve; Vagus nerve stimulation.

Fig. 1

History of VNS timeline showing the early VNS experiments in animal models, leading to the first experiment in humans. Over the past few decades, VNS has gained FDA approval for multiple diseases, including medication-refractory epilepsy, treatment-resistant depression, obesity, cluster headache, and post-stroke motor rehabilitation. As noted in the figure, all of the FDA approvals are for implanted VNS with the exception of the approval for cluster headache (which is for a form of noninvasive VNS called transcutaneous cervical vagus nerve stimulation, or tcVNS)