Vagal nerve stimulation for epilepsy and depression

Vagal nerve stimulation (VNS) for epilepsy and depression was first reviewed by the HTA in 2009. 

  • In 2013, a review of VNS medical literature was conducted to determine if newly available evidence published since 2008 was likely to change the original coverage determination. The technology was not selected for rereview.
  • In 2019, the HCA director selected VNS for rereview based on newly available evidence published since the 2009 assessment which could change the original coverage determination.
  • In 2020, VNS was rereviewed.

Status: Decision completed

Policy context

Concerns about safety, efficacy and costs regarding whether vagal nerve stimulation (VNS) provides adequate treatment for epilepsy and depression. VNS has been shown to affect blood flow to different parts of the brain, and affect neurotransmitters which are implicated in depression. Important clinical questions remain, especially around the efficacy of using of VNS to treat epilepsy and depression.

Primary criteria ranking

  • Safety = High
  • Efficacy = High
  • Cost = High
Documents (all assessments)

Assessment (2020)

Evidence update literature search (2013)

Assessment (2009)

Assessment timeline (2020)

  • Draft key questions published: October 16, 2019
  • Public comment period: October 16 to 29, 2019
  • Final key questions published: November 18, 2019
  • Draft report published: February 26, 2020
  • Public comment period: February 27 to March 30, 2020
  • Final report published: April 13, 2020
  • HTCC public meeting: May 15, 2020


Vagal, or vagus, nerve stimulation (VNS) is a neuromodulatory therapy that sends electric signals to the brain. A small device, called a pulse generator, is implanted into the left side of the chest to produce repeating, low-level pulses of electrical current along the vagus nerve to the brain. Transcutaneous VNS (tVNS) targets the cutaneous receptive field of the auricular branch of the vagus nerve (ABVN) at the outer ear, and can be a noninvasive alternative to the implanted or invasive VNS for some conditions. The mechanism of action of VNS is not fully understood, but is assumed to involve the immunomodulatory action of the vagus nerve resulting in anticonvulsant effects and changes in mood, behavior, and cognition.