Gut, brain and sleep
Vagus nerve stimulation for migraine: how it works and what the evidence shows
Non-invasive vagus nerve stimulation is a treatment in which a handheld device, held against the side of the neck for two minutes at a time, sends a mild electrical signal to the vagus nerve. It is cleared by regulators in the United States for migraine and cluster headache. In a randomised trial it relieved migraine attacks in more people than a sham device at 30 and 60 minutes. It is an option alongside, or for some people in place of, tablets.
In short
- The device is used from outside the body. Nothing is implanted.
- Evidence is strongest for treating attacks of episodic cluster headache and acute migraine.
- Evidence for preventing migraine is weaker.
- It should not be used by people with a pacemaker or other implanted electrical device.
- A neurologist should confirm the diagnosis of migraine first.
What is migraine?
Migraine is a disorder of the brain’s pain and sensory pathways. Attacks cause a throbbing headache, often on one side, with nausea and sensitivity to light and sound, lasting from four hours to three days. The gut is involved too: the stomach empties slowly during an attack, which is why tablets may work poorly once nausea has set in.
How might stimulating the vagus nerve help?
The vagus nerve carries signals to the brainstem, close to the centres that process head pain. Laboratory studies suggest that stimulating it dampens activity in the pain pathway of the face and head and reduces the release of chemicals that sustain a migraine attack. The exact mechanism in people is still being studied.
What do the trials show?
Treating a migraine attack
In a randomised trial comparing the device with a sham device, more people were free of pain at 30 minutes and at 60 minutes with real stimulation. At two hours, about 30 percent were pain-free with the device and about 20 percent with the sham; this difference was not statistically firm.
Preventing migraine
Trials of daily use to prevent attacks have given mixed results. The benefit, if any, appears modest.
Cluster headache
Trials support its use for attacks of episodic cluster headache, and as an add-on for prevention.
The device is a real option with a modest effect. It is not a replacement for a full migraine plan.
Who might consider it?
- People who cannot take, or do not tolerate, the usual migraine tablets
- People who are using painkillers on many days of the month and need to cut down
- People who prefer a treatment without medicine
- People with cluster headache, under a neurologist’s care
Who should not use it?
Not suitable if you have
- A pacemaker, an implanted defibrillator, a cochlear implant or any other implanted electrical device
- Known narrowing of the arteries in the neck
- A metal plate or implant at or near the neck
- Had the vagus nerve cut in the neck
It has not been studied in pregnancy. Tell your doctor about any heart rhythm problem or history of fainting.
How is it used?
A little conductive gel is applied to the device. It is held against the side of the neck, over the pulse, and the strength is raised until you feel a firm tingling and a slight pull at the corner of the mouth. Each stimulation lasts two minutes. For an attack, stimulations are given at the onset of pain and repeated as advised.
In my practice, the first session follows an assessment, and it is combined with attention to sleep, meal timing, hydration and known triggers. See vagus nerve stimulation therapy.
What are the side effects?
Tingling or redness at the site, a brief twitch of the neck or lip muscles, and occasionally dizziness. They pass when the stimulation stops.
What else helps migraine?
- Regular sleep and meal times; missed meals are a common trigger
- Enough water through the day
- Limiting caffeine to a steady, moderate amount
- A headache diary to identify triggers
- Regular aerobic exercise
- Slow breathing practice. See ways to stimulate the vagus nerve
- Preventive medicines, when attacks are frequent, as prescribed by your neurologist
When should I see a doctor urgently?
Seek emergency care for
- A sudden, severe headache that peaks within a minute
- Headache with fever, a stiff neck, confusion or a seizure
- New weakness, numbness, loss of vision or difficulty speaking
- A new kind of headache after the age of 50
- Headache after a head injury
Questions patients ask me
Can vagus nerve stimulation replace my migraine tablets?
For some people it reduces the number of tablets needed. That decision is made with your neurologist. Do not stop a prescribed preventive medicine on your own.
Does the stimulation hurt?
No. It causes a tingling or buzzing sensation and a mild tightening of the neck muscles.
How quickly does it act?
In the trial, the difference from the sham device was seen at 30 and 60 minutes.
Is this the same as the implanted device used for epilepsy?
No. That device is placed surgically. The device described here is applied from outside for a few minutes at a time.
Sources
This page is written for patients and is based on the guidelines and studies below. It is for education and does not replace a consultation.
- Randomised trial of non-invasive vagus nerve stimulation for acute migraine (PRESTO). Tassorelli C et al. Neurology. 2018. PubMed 29907608
- Review of the vagus nerve in the microbiota-gut-brain axis. Bonaz B et al. Front Neurosci. 2018. PubMed 29467611
- Review of the microbiota-gut-brain axis. Cryan JF et al. Physiol Rev. 2019. PubMed 31460832