Over 2.8 million people suffer from treatment-resistant depression. And, they aren't the only ones who struggle to find relief. Treatment-resistant variants of neurological and mood disorders are painful, frightening, and reduce a patient's quality of life.
These variants may be more common than you think.
Transcutaneous vagus nerve stimulation is a breakthrough, non-pharmacological treatment for neurological and mood disorders.
The vagus nerve is the primary nerve in the parasympathetic nervous system. It runs up the right and left sides of the human body.
Scientists have discovered this nerve plays a role in disorders as varied as bipolar depression, epilepsy, ADHD, and severe depression.
The FDA approved vagus nerve stimulation (VNS) as a treatment for bipolar and unipolar depression in 2005. Today, less-invasive versions of the nerve-stimulating device are widely available.
These devices are external to the body, or "transcutaneous."
Studies show these devices are generally safe. And, they hold untapped therapeutic potential for those who struggle with mood, sleep, pain, and other health issues.
Read on for a guide that covers everything you need to know about this technology.
Transcutaneous Vagus Nerve Stimulation, or tVNS, is a therapeutic technique to treat symptoms affected by the vagus nerve. It uses a device to stimulate the vagus nerve with precise electrical pulses.
Professionals sometimes call tVNS "noninvasive vagus nerve stimulation," because it is not a surgical procedure or implant.
Conventionally, the left vagus nerve carries the electrical signals up to the brain stem. Then, it distributes them to specific regions of the brain.
Transcutaneous Vagus Nerve Stimulation delivers electrical signals through the skin, via a non-permanent device. Early studies show tVNS elevates the GABA and noradrenaline levels of the brain.
This elevation has a range of impacts on the brain, mind, and parasympathetic nervous system. GABA levels, in particular, are levels of an amino acid that inhibits or modulates neuron excitement (and over-excitement).
GABA reduces anxiety, and it's associated with thinking clearly in stressful situations. People with anxiety, sleep disorders, and even schizophrenia have notably low GABA levels.
Noradrenaline is the same molecule as norepinephrine. It is both a hormone and a neurotransmitter, depending on where it is in the body. Norepinephrine modulates the body's immune response.
Think of the way Epi-Pens halt allergic reactions. Norepinephrine is the body's natural Epi-Pen.
But, that is not the only function of noradrenaline. It also enables cells, particularly nerve cells, to communicate with each other. By facilitating communication, norepinephrine modulates:
By affecting GABA and noradrenaline levels, tVNS can alter the thoughtful and emotional functions of both the brain and the central nervous system.
TAVNS is a specific technique—and device—under the tVNS umbrella. TAVNS stands for "Transcutaneous auricular vagus nerve stimulation." You might see it abbreviated taVNS.
This unique form of VNS uses a device that stimulates the vagus nerve through the ear.
Ear and scalp massages that stimulate the vagus nerve with gentle pressure have been popular at spas for a few years now. Masseuses and other wellness practitioners have spread this stress-busting practice to healthcare groups.
But the impact of a massage's pressure is limited. Once the massage is over, the relaxing effect may last only the rest of the day. By tomorrow, you're back to feeling stressed.
TAVNS uses the same sensitive entry point to the vagus nerve—the ear—as masseuses do. But they stimulate the nerve with an electric current, rather than physical pressure.
The electrical stimulation affects the nerve more deeply, and its changes last longer.
How different is TAVNS from other transcutaneous VNS therapies?
Different tVNS devices stimulate the vagus nerve with different stimuli, at different points. The most frequently used points are:
Few apples-to-apples studies have been conducted to compare the effectiveness of different points of contact. That said, ear sites are particularly promising.
Experiments that utilized VNS to treat epilepsy targeted the left-side cervical vagus nerve branch. The cervical vagus nerve branch, or CVN, has a unique shape and placement.
In 2018, researchers discovered that CVN incorporates both parasympathetic and sympathetic nerve fibers.
It provides three distinct types of information to other parts of the body. These discrete types of information move through different pathways.
The CVN also has a uniquely significant association with vasodilation. Stimulation via the CVN seems to have anti-inflammatory effects.
Recent anatomical studies of the CVN revealed similar properties in another, nearby branch. The auricular branch of the vagus nerve has similar properties to the CVN.
In 2020, scientists consolidated research on the auricular branch of the vagus nerve (ABVN). The research revealed two sites that offer the most therapeutic potential. These sites are:
Like the CVN, the ABVN incorporates nerves from both the sympathetic and parasympathetic nervous systems. This, and its location, give the AVBN a unique ability. Unlike other vagus nerve sites, the AVBN can affect:
The multitude of systemic points of impact makes the ABVN a useful site for VNS interventions.
While research is preliminary, ABVN stimulation shows potential for longer-lasting therapeutic effects than other tVNS sites.
Vagal stimulation affects multiple physiological systems.
When you consider the primary effects of tVNS, remember that vagal nerves are not uniform. The differences between different patients' vagal nerve structures and traits can lead to varied outcomes.
With that in mind, vagal nerve stimulation produces many effects consistently. The most reliable, studied effects include the following:
These primary effects subsequently impact human physiology widely. These impacts are the basis for tVNS as a therapeutic option.
Stimulation of the vagus nerve may improve the health and wellbeing of people struggling with a range of stressors and symptoms. Here's what the research shows us so far about tVNS' impact on different conditions.
Transcutaneous VNS stimulation has alleviated depression symptoms in studies. It shows particular promise in studies of tVNS as a treatment for severe or major depression.
One of the most robust studies demonstrated tVNS as a viable treatment option for patients with treatment-resistant depression. Before the study, patients had poor results from pharmacological treatment.
67.7% of depression patients in the 5-year clinical trial found significant symptom reduction with VNS when they had little-to-no reduction through previous interventions.
And, over 43% of the depression patients went into remission entirely, for the first time. This is almost twice the first-time remission rate of the control group.
Other studies have demonstrated similar results. One recent analysis noted a positive impact on patients with depression. Authors recommended tVNS to augment pharmaceutical treatment.
Another systemic review intended to determine the optimal clinical application of tVNS. They compared different site locations and current volumes. These study authors refrained from conclusive statements.
But they did say tVNS has the potential to provide great relief, and it does not risk serious side effects. So, tVNS is a reasonable treatment for a patient to try at home.
TVNS may benefit people who struggle with anxiety or PTSD symptoms. Stimulating the vagus nerve appeared to enhance the function of serotonin in some animal studies.
This, and its regulating impact on the amygdala, can facilitate symptom relief.
In a different report, PTSD patients also experienced symptom relief, improved fear-extinction, and improved sleep with tVNS intervention. Specifically, the intervention reduced the frequency of nightmares.
In 2020, a small 4-week study demonstrated taVNS' potential as an insomnia treatment. In the study, insomnia patients:
Unlike other insomnia medications, taVNS has no known serious side effects.
People who struggle with acute or chronic pain may see significant benefits from tVNS therapy. Studies indicate that tVNS is an effective pain-management strategy in certain circumstances.
One case study shows tVNS offered effective pain relief for a patient with a rib fracture.
Another case study showed tVNS' efficacy as an opioid reduction treatment.
Currently, studies exploring tVNS as a treatment for fibromyalgia are ongoing.
People with cluster headaches and migraines may benefit from tVNS.
The FDA approved tVNS as a cluster headache treatment in 2018. It determined that tVNS treatment can reduce the frequency of "cluster attack" headaches for chronic sufferers.
There are notable connections between the vagal nerve and inflammatory responses.
Stimulating the vagus nerve enhances its anti-inflammatory properties. As a result, it shows promise as a treatment for inflammatory autoimmune conditions.
One study shows tVNS intestinal and systemic inflammation in mice. This may point us towards a future tNVS therapy for inflammatory bowel diseases.
In 2021, Estival launched a study of tVNS therapy for osteoarthritis. The study is ongoing.
Scientists have discovered the vagus nerve is critical to a patient's sense of hunger or fullness. It modulates the "brain-gut axis" of the digestive and parasympathetic nervous systems.
This has wide-reaching effects. Preliminary research suggests tVNS has the potential to:
Currently, researchers know the vagus nerve regulates how the brain processes food cues.
Scientists hypothesize that the reason gut bacteria impact various physiological responses, including the immune response, is they affect the vagus nerve.
The pharmaceutical drug metoclopramide demonstrates this connection. The drug treats gastroparesis and GI disorders by mediating the vagus nerve's effect. It modulates the nerve's impact on digestive tract muscles.
The drug does this indirectly, as a dopamine receptor agonist.
Recent studies suggest tVNS can offer similar digestion benefits directly. In 2020, researchers determined TAVNS improves eating disorder recovery—including recovery from anorexia—when clinicians add it to existing therapies.
The vagus nerve mediates emotional memory formation. It's also involved in core executive functions. The nerve's impact on memory and focus is notable.
As a result, scientists have proposed tVNS as a potential ADHD treatment option. It also may mitigate the effects of aging.
Vagal nerve stimulation improves cognition, in part, by reducing stress. It's easier to recall things when you're less stressed out. It also reduces negative self-talk, which can get in the way of learning.
As a result, some researchers recommend daily tVNS for adults over age 55.
If you want to treat a serious medical condition with vagus nerve stimulation, talk to a doctor. Doctors may recommend a VNS device implant below the collar bone.
Many people can find symptom relief, or improve their well-being, by using tVNS devices and techniques on their own. If that describes you, consider non-surgical options.
There are a few reliable methods people use to stimulate their vagus nerve at home. Some methods are entirely independent, while others involve help from a partner.
You can stimulate the vagus nerve by applying cold water to the side of your face and neck. One study shows this method of cold stimulation increases heart-rate variability (HRV). Subsequently, stress-related markers diminished.
You can massage your vagal nerve by applying pressure to points in your ear. A partner can stimulate your vagus nerve concurrently by massaging points in your abdomen and feet. At each point, these massages improve your vagal tone.
Slow breathing can stimulate the vagus nerve. Try slowing your breaths down to six exhales per minute.
Singing also stimulates the vagus nerve. In part, this is because singing involves controlling your breathing.
However, other ways of engaging with music—listening, entrainment, and playing instruments—similarly affect the vagus nerve. Research is ongoing.
Finally, you can stimulate your vagus nerve with a tAVNS device at home. A tAVNS device stimulates your vagus nerve with an electric current at a site in the ear. The current is conducted through a gel paste on the electrode.
One benefit of the device is duration. You can continue to use it for much longer than you can undergo a massage. It fits in easily with the rest of your day.
TAVNS devices are often compatible with smartphones. Some have adjustable currents. Some people stimulate their vagus nerve by using a TENS unit and an earpiece adaptor.
Transcutaneous vagus nerve stimulation can soothe your whole body. As scientists continue to research this new technology, we learn more about its benefits.
If you're interested in improving your health or wellbeing, consider a tVNS stimulator.