Noninvasive Vagus Nerve Stimulation vs. Invasive

Written by, Vivi Yu on April 27, 2022
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Did you know that stress, anxiety, and depression increased by approximately 25% globally once the pandemic hit? Social distancing, health concerns, and work changes have negatively affected many people's mental health.

Have you heard of the vagus nerve? This critical cranial nerve plays an essential role in stress management. Noninvasive vagus nerve stimulation devices show promising effects on health and wellness.

But how does this differ from traditional implanted devices? Before contacting your local physician about invasive vagus nerve stimulation devices, check out our complete guide on the two types of vagus nerve stimulation therapy.

You may be surprised that invasive treatments are only offered for specific diagnoses, and noninvasive devices can hold the secrets to many similar benefits. Luckily, we will break down what the vagus nerve does, how treatments work, and how you can get started today, so keep reading for more information!

What Does the Vagus Nerve Do?

The vagus nerve is one of twelve cranial nerves in the body. Also referred to as cranial nerve X, the vagus nerve has sensory and motor components. It plays a critical role in communicating between the brain and digestive system while also helping with autonomic nervous system functions. Here is a more comprehensive list of what the vagus nerve does:

  • Regulate heart rate
  • Aid in proper digestion
  • Regulate breathing rate
  • Assists with other cardiovascular activity
  • Facilitates reflexive responses (e.g., coughing, sneezing, swallowing)

It is the longest cranial nerve, branching from the brain stem to the lower parts of your colon. As mentioned above, part of its role is to stimulate muscle groups and reflexes. Yet, it also supplies sensory functions, such as:

  • Somatic sensation around the ears and throat
  • Visceral sensation for the digestive tract
  • Taste

The vagus nerve's role in taste is minimal, but it plays a key part in your gag reflex. A straightforward way physicians can start narrowing down problems with the vagus nerve is through a gag reflex test. If a cotton swab on the back of a patient's throat does not elicit a gag, further testing is initiated for vagal nerve damage.

Lack of Vagal Stimulation

Symptoms of vagal nerve damage may vary depending on where the damage or lack of nervous activity occurs. As the vagus nerve exits the brainstem, it branches in several directions.

Understanding the location of these branches provides insight into understanding the 'why' component behind symptoms. Here are a few key vagal nerve branches in the body:

  • Jugular fossa (e.g., meningeal branch and auricular branch)
  • Pharyngeal branch
  • Laryngeal nerve
  • Superior cardiac branches
  • Inferior cardiac nerve
  • Bronchial branches
  • Esophageal branches
  • Gastric branches
  • Celiac branches
  • Hepatic branches

When there is a lack of vagus activity, there may be general signs and symptoms of vagal damage, including:

  • Gastroparesis
  • Impaired speaking
  • Change in voice
  • Loss of specific reflexes
  • Lower heart rate and blood pressure
  • Depression

You may also hear the term: vagus nerve dysfunction (VND). VND can cause debilitating and life-changing effects, including your mental health.

What Do Vagal Nerve Studies Show?

Most recently, studies have been looking at VND in long-COVID patients. Some of the symptoms researchers are seeing in long-COVID patients include:

  • Voice changes
  • Dysphagia
  • Dizziness
  • Tachycardia
  • Orthostatic hypotension
  • Diarrhea

Does this sound familiar? In a pilot study of nearly 350 post-COVID patients, over 65% showed at least one symptom of VND.

The researchers narrowed this list to 22 patients. More than 85% of the cohort had three VND symptoms. The top three VND complaints were:

  1. Diarrhea (nearly three-quarters of subjects)
  2. Tachycardia (approximately 60%)
  3. Dizziness (almost 50%)

Vagal nerve changes were noted via ultrasound in the neck and thoracic region. Parts of the vagus nerve showed thickening (likely due to inflammation) or flattening. In-person assessments indicated changes in swallowing patterns and hernias.

The importance of this study backs structural and functional changes in the patient's vagus nerve and correlates them to exact symptoms. In the case of COVID-19, it suggests the need for more research on its role in the central nervous system that potentially leads to VND.

What Is Noninvasive Vagus Nerve Stimulation?

Vagus nerve stimulation is exactly how it sounds: a technique that helps vagus nerve stimulation. It is used mainly for patients who have an underactive or inactive vagus nerve.

A noninvasive vagus nerve stimulator uses electrical stimulation or neuromodulation. These devices are also known as transcutaneous vagus nerve stimulation (tVNS).

What is tVNS?

It is a small electrical stimulation device typically placed on the skin behind the ear or neck. The tVNS device sends electrical currents through the body that helps re-engage the vagus nerve. A tVNS device could help with symptoms relating to:

  • Digestion
  • 'Fight or Flight' response
  • Immune system
  • Parasympathetic nervous system

Your parasympathetic nervous system helps promote homeostasis, and using a tVNS device can assist in rebalancing bodily functions, hormones, and health.

What Is tVNS Used For?

A tVNS device is not a substitute for diagnosing and treating medical conditions. It has been used as part of a therapeutic approach for managing symptoms related to:

  • Difficult to treat depression
  • Specific types of epilepsy
  • Anxiety disorders
  • Headaches
  • Alzheimer's disease
  • And more

Two studies highlight how more research is needed to see the full effects of a tVNS device. The first study researched difficult to treat depression via VNS therapy. This study looked at implanted VNS devices (which will be discussed later on), but it sheds light on how vagal nerve stimulation can help with physical and mental health symptoms.

Implanted VNS devices are currently FDA-approved for treating forms of depression and have fewer side effects than electroconvulsive therapy (ECT). However, researchers suggest the effects may be slower.

Experts recommended that VNS therapy be used as a complementary treatment form and that there are some risks of implanting a device. The safety of implantable VNS devices includes:

  • Surgical complications
  • Acute side effects
  • Hypomania

The safety and efficacy of long-term device implants require further studies. The second study looked at auricular vagus nerve stimulation through an external stimulation device. The goal of stimulating the auricular vagus nerve was to improve fibromyalgia symptoms such as:

  • Pain
  • Depression
  • Anxiety

They compared the group that received tVNS and home exercises to a control group that participated only with home exercises. They found that both groups showed improvements in the three factors above (e.g., pain, depression, anxiety) and quality of life. Further research was recommended to differentiate between home exercises and tVNS since both groups participated in exercises.

The tVNS group did show slightly more significant improvements in test scores. This finding indicates the need for longer studies and more specific treatment guidelines.

Where Is a tVNS Device Placed?

A tVNS ear device is the most commonly used location. In-depth studies have used functional MRIs to assess parts of the ear and tVNS' effects. They found that the tragus and concha are two regions that could be used for vagal modulation.

The benefit of these devices is that you can control vagus nerve stimulation at home. The device is safe and user-friendly, with easy-to-read instructions. Here is how to effectively place and use the tVNS device:

  • Clean the tragus area with water or a wipe
  • Firmly attach electrodes
  • Slowly increase intensity
  • Wear for 15 minutes

The main effects of tVNS on the tragus are boosting vagus activity and vagal tone. Vagal tone helps with blood pressure regulation, heart rate variability, relaxation, and overall wellness. Some results are harder to quantify and measure, but participants have reported improvements in their health and wellbeing.

What Is Invasive Vagus Nerve Stimulation?

When you search the internet for 'how to stimulate the vagus nerve,' you will likely encounter multiple articles on surgical VNS therapy. This procedure involves implanting a small electrical device, usually in the chest or neck region.

A qualified physician makes a small incision during the surgical procedure and connects the device to the vagus nerve. After a few weeks, the pulse generator is turned on. Most neurosurgeons recommend starting at a low impulse and slowly increasing.

For epilepsy, most people will bring a magnet towards the generator when they feel a seizure coming on. The electrical impulses are released to stop an oncoming seizure.

However, this form of VNS therapy is much more invasive. It has a higher risk for:

  • Vocal cord paralysis
  • Infection
  • Dyspnea
  • Indigestion

Invasive vagal stimulation also has a more limited population group. It is not recommended for patients with a single vagus nerve, asthma, arrhythmias, ulcers, or insulin-dependent diabetes.

Invasive vs. Noninvasive Vagus Nerve Stimulator

When weighing the pros and cons of invasive and noninvasive vagus nerve stimulators, it is important to mention that a skilled neurosurgeon must recommend and perform surgery for invasive stimulators. It is still beneficial to consult a physician before starting any treatment intervention, even a noninvasive stimulator.

Invasive stimulators will cost more and are permanent options. You will have higher risks for side effects and complications. However, it could target more specific receptors on your vagus nerve.

Noninvasive vagus nerve stimulators are cheaper, easy to use at home, and avoid more severe side effects. Studies found that tVNS devices used on the ear trigger an acupuncture point which affects:

  • Connectivity between amygdalae
  • Pain receptors
  • Limbic system

Like acupuncture, you can use a tVNS to stimulate vagal activity, which can help with sleep quality and mood. It also helps your body maintain a healthy balance. Other ways that you can stimulate your vagus nerve without opting for surgery include:

  • Singing or humming
  • Deep breathing
  • Meditation
  • Cold therapy
  • Massage
  • Exercise

Studies show that high-intensity interval training helps decrease arrhythmias and improves heart rate variability. If high-intensity training isn't on your radar, mild exercise or yoga can help aid digestion.

Calming activities such as meditation and deep breathing help reduce sympathetic nervous system activity and engage your parasympathetic nervous system. Using a safe, at-home tVNS unit, you can start facilitating better heart rate variability and parasympathetic nervous system activation.

These healthy methods will promote longer-term benefits and vagal tone compared to only using an implanted device. Activities such as meditation and exercise can also help with cardiovascular, musculoskeletal, and mental health.

Parasympathetic Nervous System and VNS Therapy

One of the downsides of invasive vagus nerve stimulation is that it is only FDA-approved for two diagnoses:

  • Refractory epilepsy
  • Treatment-resistant depression

Unfortunately, the rest of the population dealing with other symptoms likely won't qualify for this surgery. For many individuals, the sympathetic nervous system is in constant overdrive, leading to feelings associated with stress and anxiety.

Your autonomic nervous system is responsible for blood pressure, heart rate, breathing, and digestion. It splits into two branches: parasympathetic nervous system and sympathetic nervous system. When you feel calm and rested, your parasympathetic nervous system is engaged.

It helps reduce stress and inflammation and returns the body to homeostasis. VNS therapy can help activate a sluggish parasympathetic nervous system. In return, you may notice improvements in:

  • Mood
  • Immunity
  • Blood pressure

Reducing chronic stress is not an indicator for an invasive vagus nerve stimulation procedure, making a tVNS unit safer and applicable for more population groups.

Improve Your Health and Wellness

A noninvasive vagus nerve stimulation device can help reduce the effects of chronic stress. It can improve vagus activity by reducing sympathetic nervous system activity, promoting homeostasis, and aiding overall health and wellness.

While VNS therapy has widely been used for epilepsy and depression, it shows promising effects for even more physical and mental health concerns. The benefit of an at-home unit is that more people can safely test out the benefits themselves!

Are you ready to get started? Contact us today to get started with your next order!


Vivi Yu
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