The non-profit Mental Health America shows the United States is in the midst of a mental health crisis. Over 50 million U.S. adults have a mental illness. 24.7% of adults report an unmet need for treatment.
And, over 50% of adults with mental illnesses are not receiving any treatment at all.
Barriers to mental health care include the monetary cost, barriers to diagnosis, and long waitlists.
What if there was a way through those barriers? What if there was a device that could relieve many mental health symptoms at home, without a prescription?
That’s the potential of a tVNS device.
Transcutaneous vagus nerve stimulation—or, tVNS—is a groundbreaking therapy. Over a decade of research demonstrates the vagus nerve has the power to affect the mind and body in wide-ranging ways.
Your vagus nerve impacts your mood, your appetite, how well you sleep, and even your cognition.
TVNS stimulates the vagus nerve with an electric current. Studies indicate this stimulation triggers a physiological chain reaction that improves wellbeing.
But how exactly does a tVNS device work? Is it safe? And how might it impact your health personally?
Learn the answers to these questions—and more—in this tVNS device explainer.
What is the Vagus Nerve?
The human body has two vagal nerves that run down the sides. Each vagus nerve is one of the primary pathways of the parasympathetic nervous system.
The parasympathetic nervous system (PNS) is the counterpart to the central nervous system (CNS). Both nervous systems communicate sensory information and motor signals throughout our bodies.
The PNS controls and regulates involuntary physical responses, like breathing or digesting food. It does this by:
- Signaling receptors in organs directly
- Moderating CNS signals
- Sending signals that trigger hormonal and neurochemical responses
As primary PNS nerves, the vagal nerves have wide-ranging effects on the body. They play a role in modulating communication among cells during complex biological responses, like immune responses and blood pressure.
The vagus nerve incorporates diverse nerve cells, called neurons. Somatic neurons, which carry and process sensory information, share a sheath with visceral neurons and motor fibers.
This is the longest cranial nerve in the body. The vagus nerve starts at the brain stem, then runs down the neck and sides of the body. The vagus nerve ends in the digestive system, innervating the visceral organs and the colon.
Vagus Nerve Dysfunction
If the vagus nerve is dysfunctional, that affects the whole body. But, two vagus nerve dysfunctions are well-known:
- Vasovagal syncope
Gastroparesis is a result of an underactive or damaged vagus nerve. It cannot send strong enough signals to the organs in the digestive tract. As a result, the muscles don’t contract to move food along effectively.
Doctors typically treat gastroparesis with medication or surgery.
Vasovagal syncope stems from an overactive vagus nerve. The vagus nerve to the heart overreacts to certain sensory stimuli, like heat or pain.
The overreaction causes an acute blood pressure drop. This can cause the patient to faint or get dizzy.
In recent decades, research has implicated the vagus nerve in a much wider range of health problems. It also indicates that vagus nerve stimulation may provide a solution.
What is Vagus Nerve Stimulation (VNS)?
Vagus nerve stimulation (VNS) is a category of physical therapeutic practices. VNS therapies aim to provide pain and inflammation relief, boost mood, or improve diet or sleep.
These therapies stimulate the vagus nerve, which increases its activity. This activity, called the vagal tone, is made up of the baseline signals that flow to and from the nerve.
Increased vagal tone decreases overall stress and increases heart rate variability (HRV). A high HRV indicates good health. Increased vagal tone improves the vagus nerve’s functions.
There are a few different approaches to stimulating the vagus nerve.
Some people massage the vagus nerve. Others stimulate the vagus nerve with cold water, by splashing it on the sides of their face and neck. Breathwork and binaural beats can strengthen the nerve’s vagal tone during meditation.
But, the strongest, most direct way to stimulate the vagus nerve is with an electric current. To do this, clinicians may use a VNS device.
In 2005, the FDA approved VNS implants as a treatment for depression, bipolar, and epilepsy. A VNS implant is a device with three components:
- The pulse generator
- An insulated wire
- Coil electrodes
Surgeons place the implant on the left side of the patient’s chest, below the collar bone. Then, they wrap the coil electrodes around the vagus nerve inside the neck. The wire connects the electrodes to the pulse generator.
Finally, the device is permanently sewn into the muscle.
The VNS implant’s electric pulses can be programmed remotely. Different patients respond to different current strengths and pulse frequencies.
VNS implants helped some patients with treatment-resistant epilepsy and depression experience symptom reduction.
However, VNS implant surgeries are a fairly risky option.
If the surgical site becomes infected, the consequences can be deadly. Moreover, some patients experience side effects like facial muscle paresis, shortness of breath, and trouble speaking.
Still, for patients with severe epilepsy or depression, the increased quality of life VNS implants offer is worth the risk of side effects. For most other patients, though, alternatives are preferable.
The Evolution of VNS Technology
Back in 2005, VNS implants were the only technology available to stimulate the vagus nerve electrically. In the subsequent decades, engineers experimented with less-invasive designs.
Discoveries about the neuro-therapeutic potential of targeted electric currents accelerated medical device development.
Brain stimulation is a growing field of research. Innovations in electroconvulsive therapy (ECT) and transcranial magnetic stimulation (TMS) spurred the field forward.
Finally, in 2015, engineers developed an entirely noninvasive vagus nerve stimulation technology: the tVNS device.
What is a tVNS Device?
A tVNS device is a transcutaneous vagus nerve stimulator. Like the original VNS implant, a tVNS stimulates the vagus nerve with an electric current.
But, unlike the VNS implant, a tVNS stimulator is external. Nobody has to implant it surgically. Instead, it stimulates the vagus nerve through points on the skin.
One other key difference? A tVNS device has consistent electrical strength, and the user controls the frequency.
TVNS: Auricular vs. Cerival
Today, most transcutaneous VNS devices are either auricular (taVNS) or cervical (ctVNS). The vagus nerve has multiple branches. Different branches are potential sites where transcutaneous stimulation is effective.
Auricular Transcutaneous Vagal Nerve Stimulation (taVNS)
TaVNS devices connect to the vagus nerve via the ear. This branch of the vagus nerve is the auricular branch. Colloquially, it’s called the Arnold’s nerve.
The auricular branch of the vagus nerve incorporates sensory reception cells and cells that respond with physiological functions.
It is unique in that it’s an unusually accessible branch of the nerve, and it creates a small “field” of receptor cells in two sites in the ear.
Stimulating the receptor cells streamlines activation and increases the therapy’s efficacy. These cells are readily able to distribute the electric current to the brainstem.
This distribution closely mimics the sensory input that triggers modulation in a healthy vagus nerve. Activating modulation helps the vagus nerve effectively modify physiological responses, like the immune response.
Cervical Transcutaneous Vagal Nerve Stimulation (ctVNS)
In contrast, ctVNS stimulates the vagal nerve through points on the skin of the neck. While it still stimulates the vagus nerve, it does so through different pathways.
In 2021, researchers discovered ctVNS stimulation could combat fatigue by activating the LC-NE pathway. This specific pathway activation is easier from the neck site than any site in or around the ear.
Both taVNS and ctVNS have broad treatment potential.
How Does tVNS Work?
Unlike the VNS implant, a tVNS device is portable. You can easily use it at home.
A tVNS device has a rechargeable battery that powers the pulse generator. Like a VNS implant, a tVNS device has an electric pulse generator, a wire, and electrodes. Unlike an implant, a tVNS device has an external attachment.
Most tVNS devices include attachments that are intuitive to use. Auricular tVNS devices have an earpiece fitted with electrodes.
When placed correctly, the earpiece will set the electrodes against the tragus or cymba concha. At these two sites, in and behind the ear, the vagus nerve is close to the surface.
Some tVNS devices require users to dab conductive gel on the sites. This lets the electric current pass through the skin to stimulate the nerve more seamlessly.
Researchers are still conducting experiments to determine the optimal parameters to treat different conditions with a tVNS device.
Many tVNS devices have an interface that makes it easy to adjust the strength and frequency of the electric current. This is similar to the interface that lets users adjust the parameters of a TENS unit.
For safety, it’s wise to begin tVNS therapy on the lowest setting, unless a doctor gives you a different recommendation. Many people who use tVNS devices independently start small. Initially, users start at 15 minutes per day.
How Does tVNS Therapy Impact Users?
Transcutaneous VNS devices have a range of effects on users. Research indicates significant potential for an overall positive impact. But, it’s important to remember that the impact differs from person to person.
This is because many factors contribute to physical illness and wellness. The vagus nerve is critical to cell communication, and it starts and ends different physiological responses.
But, physical components like our endocrine system’s production of different hormones, the endocannabinoid receptors in different cells, and the function (or dysfunction) of mitochondria also impact communication and responses.
The way these parts of our cells differ means they interface in diverse ways with our vagus nerve. As a result, different individuals will feel different effects.
Still, tVNS devices have been used for long enough that we can recognize patterns of impact
WARNING: History Heart Attack, or Vasovagal Syncope
If you have a history of heart attacks or vasovagal syncope (fainting), do not use a tVNS device without a doctor’s supervision. Most tVNS studies explicitly exclude patients with pacemakers from participating.
A tVNS activates the vagus nerve. These conditions can be the result of a vagus nerve that is already over-active. Talk to a doctor to mitigate the risk tVNS may worsen these conditions.
Researchers have observed several benefits from tVNS device use in most cases. Most benefits can be traced back to increased vagal tone and improved modulation of the Default Mode Network in the brain.
Pilot studies, case studies, and initial trials show six key benefits of tVNS therapy.
Studies indicate that tVNS therapy is a useful, acute treatment for sleep disorders. One clinical trial demonstrated patients found significant relief from insomnia and fatigue with two 30-minute taVNS treatments per day.
Patients typically tolerate taVNS well. In the study, patients were able to adjust the intensity of the current themselves.
Multiple studies have discovered evidence that tVNS therapy is an effective pain management tool.
It is particularly useful to manage pain that stems from autoimmune conditions (including IBD), as the vagus nerve modulates the immune response in the body.
Reports indicate patients likewise use tVNS to effectively treat acute pain from injuries, cluster headaches, and chronic migraines.
Several ongoing studies are investigating tVNS therapy as a treatment for depression, bipolar, and other mood disorders.
Existing studies show promising results. And, tVNS therapy has a far lower incident rate of side effects than many antidepressants.
As such, using tVNS to improve your overall mood may be worthwhile.
The vagus nerve connects directly to the organs involved in digestion. It modulates the involuntary muscle processes involved in digesting food. It also affects our perception of hunger and fullness.
Patients have reported tVNS therapy as a useful, additional therapy for treating malnourishing conditions. This has included eating disorders like anorexia, nausea and vomiting, and binge eating.
In one 2019 study, tVNS helped reduce the prolonged fear response in patients with anxiety disorders and PTSD. Research also indicates that tVNS therapy prevents intrusive thoughts.
Relating both anxiety reduction and sleep improvement, tVNS use has been known to reduce the severity and frequency of nightmares for some users.
Researchers note that tVNS therapy improves focus for some individuals. Scientists at Elsevier have proposed tVNS as a therapy for people with ADHD who want to improve focus and attention.
Contemporary research likewise indicates that tVNS therapy has improved memory recall in adults over age 55.
There are very few known risks of tVNS therapy. It is well-tolerated by most people.
In some studies, a small percentage of participants developed headaches and vasovagal syncope. These symptoms went away when those patients stopped tVNS.
Revitalize Your Wellbeing With tVNS
It’s possible to improve your health and wellbeing with a therapeutic tVNS device.
Sharpen your mind, heal your body, and soothe your spirit with vagus nerve stimulation. To learn more about what a tVNS device can do for you, check out our tVNS Device Stimulator information page.