Is Your Vagus Nerve Impaired?

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The vagus nerve, a crucial component of our nervous system, plays a pivotal role in maintaining equilibrium in our body. When impaired, it can unleash a cascade of symptoms and conditions that can significantly impact our quality of life.

Understanding the vagus nerve, its functions, and how its impairment can affect us is vital in navigating through the myriad of health challenges it presents [1].

Conditions and symptoms linked with Vagus Nerve Impairment (functional or structural)

  • Anxiety, Panic Attacks, PTSD [2,3]
  • Brain Fog [4]
  • Chronic Fatigue [5]
  • Cognitive Impairments [6]
  • Dysphagia and Dysarthria [7]
  • Depression [8]
  • Epilepsy and Seizures [9]
  • Insomnia [10]
  • Vertigo and Headaches [11]
  • Cardiovascular Symptoms:
    • Abnormal Heart Rate [12]
    • Fainting and Syncope [1]
    • High Blood Pressure [13]
  • Gastrointestinal Issues:
    • Digestive Issues [14,15]
    • GERD [16]
    • Gastroparesis [17]
    • Vomiting and Nausea [18]
  • Metabolic and Endocrine Disorders:
    • Obesity [19]
    • Diabetes [20, 21]
  • Autoimmune and Inflammatory Conditions:
    • Autoimmune Diseases [22]
    • Chronic Inflammation [20, 23]

What is the Vagus Nerve?

The vagus nerve is a long nerve that runs from the brain through the face and thorax to the abdomen. It is involved in regulating heart rate, controlling muscle movement, keeping a person breathing, and transmitting a variety of chemicals through the body.

It is also responsible for keeping the digestive tract in working order, contracting the muscles that empty the stomach, and regulating the secretion of enzymes [24].

What causes Vagus Nerve Impairment

Some evidence suggests vagus nerve impairment can stem from various causes, including:

  • surgical procedures [25], 
  • chronic stress [25], 
  • trauma [25], 
  • neurological disorders [25], 
  • autoimmune conditions [26], 
  • post-infection complications [26], 
  • diabetes [26], 
  • exposure to toxins and alcohol [27],
  • heavy metals [27].

Diagnosing Vagus Nerve Impairment

A thorough review of symptoms and medical history is pivotal in diagnosing vagus nerve impairment. This can be initiated with a doctor or with the help of a vagus nerve impairment assessment questionnaire:  here. For further information, visit Nurosym.

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Vagus Nerve Neuromodulation: A Glimpse into the Future of Treatment

Neuromodulation of the vagus nerve has emerged as a promising treatment for vagus nerve impairment. This method entails accurately delivering calibrated electrical impulses, effectively stimulating the vagus nerve and consequently alleviating its dysfunction, along with associated symptoms.

Originally, vagus nerve stimulation relied on high-risk surgical procedures and primarily targeted severe medical conditions such as refractory epilepsy and treatment-resistant depression. However, technological advancements have led to the development of non-invasive vagal neuromodulation devices, thereby expanding its applications to a wide range of medical conditions [28, 29].

In this context Parasym has been a pioneer, launching Nurosym, a revolutionary neurotechnology device. Nurosym has significantly altered the medical landscape by providing non-surgical vagal neuromodulation, offering therapeutic effects equivalent to invasive devices.

This device stimulates the branch of the vagus nerve on the ear, which has been found most effective, alleviating numerous symptoms and enhancing general health [30].

Nurosym, a clinically-validated CE-certified medical device, has been on the market for several years and is recommended by doctors around the world. Nurosym’s benefits have been validated in 30 peer-reviewed studies, including numerous randomised, placebo-controlled clinical trials, widely regarded as the gold standard in clinical research.

Across over 2 million patient sessions, Nurosym has demonstrated clinical effectiveness in a range of clinical conditions associated with vagus nerve impairment, with no reports of serious adverse events.

Nurosym clinical evidence

Reduced fatigue & increased energy

In order to assess and quantify the level of fatigue experienced by participants, our study employed the Pichot Fatigue Scale. There was a highly significant improvement in fatigue scores after treatment (D0 vs. D10, p<0.0001) (Figure 1).  Participants reported that the improvements in fatigue remained 1 week after stopping the treatment [31].


Figure 1. Evolution of fatigue estimated by Pichot fatigue scale during treatment (D0: day 0, D5: day 5, D10: day 10) [31].

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Reduced Long Covid Symptoms Intensity Including Brain Fog & Fatigue

After COVID-19 infection, individuals often experience a wide range of symptoms, such as fatigue, cognitive problems, depression and pain. We evaluated our proprietary neuromodulation on those suffering with Long-COVID symptoms.

Treatment starts after baseline measurement at Day 0 (D0), ending on D10, with follow up measurements one week later (D17). A very significant improvement was observed after 10 treatment sessions (D0 vs. D10: p<0.0001) (Figure 2) [31]. 

Figure 2. Evolution of Long-Covid Symptoms by Patient score during treatment (D0: day 0, D5: day 5, D10: day 10) [31].

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Reduced depression & improved mood

Studies utilising Nurosym neuromodulation have been conducted on patients, offering insights into potential therapeutic strategies for treating depression and improving mood.

Evolution of the Beck depression scale scores during treatment was performed (Figure 3). After only 5 days of therapy, the symptoms of depression were alleviated, and a noticeable improvement in the overall mood was observed [31].

Figure 3. Evolution of the Beck depression scale scores during treatment (day 0, day 5 and day 10). The individual values and the median are shown. Non parametric Friedman statistics for paired comparisons were used and followed by post-hoc Dunn’s multiple comparisons test [31]. 

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Improved Heart Rate Variability (HRV)

HRV is an indicator of Vagus Nerve activity. Improving these parameters of HRV indicate targeted stimulation of the vagus nerve and activation of specific mechanisms that reverse chronic fatigue and improve mood. One hour sessions of Nurosym favourably altered all three parameters of Heart Rate Variability (HRV), when compared to placebo (Figure 4) [32].

Figure 4. (a) High Frequency HRV is significantly increased (*p=0.001); (b) Low Frequency HRV is significantly decreased (*P=0.001); (c) the ratio of LF to HF is significantly decreased (*p=0.002) [32].

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Reduced Postural Orthostatic Tachycardia

At the two-month mark, research investigated the difference in postural heart rate change between active Nurosym neuromodulation and sham (placebo) stimulation (Figure 5).

The analysis showed that postural tachycardia (without a significant drop in blood pressure) was significantly less in patients who received Nurosym neuromodulation compared to control (postural increase in heart rate 18±10 bpm vs. 32±14 bpm, respectively, *p=0.016) [33].

Figure 5. Effect of active Nurosym modulation vs. sham stimulation on the postural change in heart rate (Δ heart rate) [33]. 

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Reduction in Inflammation

Inflammation throughout the body and brain contributes to diseases development, progression, ageing and mental health problems. The research utilising the vagal stimulation have revealed noteworthy alterations in two inflammatory biomarkers, specifically Tumour Necrosis Factor (TNF)-α and Interleukin (IL)-8.

The findings demonstrate a statistically significant reduction in these inflammatory cytokines compared to the sham group at the end of 3 months (Figure 6).  [34].

Figure 6. Changes in two inflammatory biomarkers: (a) Tumour Necrosis Factor (TNF)-α ; (b) Interleukin (IL)-8, before and after 3 months low-level tragus stimulation (LLTS) with Nurosym device [34].

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Improved blood circulation

In the case of heart failure, problems with the autonomic nervous system are a significant factor causing issues with the functioning of blood vessels. Nurosym stimulation has demonstrated the beneficial effects of acute neuromodulation on macrovascular function and blood circulation in comparison to placebo (Figure 7)  [35]. 

Figure 7. Effect of low-level tragus stimulation (LLTS) on peripheral microcirculation assessed by laser speckle contrast imaging (LSCI). Pseudo colour images on dorsum of left hand during (1) baseline, (2) occlusion and (3) Postocclusive reactive hyperemia (PORH) phase.

Blue represents lower, red represents higher perfusion rates; (B, C) Changes in blood perfusion measured over nail bed area, before and after Nurosym neuromodulation (B) and sham (placebo) stimulation (C). Markedly higher perfusion rate was seen after Nurosym neuromodulation [35]. 

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Improved memory & learning

Our clinical trials have provided compelling evidence that Nurosym device has a positive impact on cognitive function, particularly learning and recalling tasks (Figure 8).  Results have shown a significant benefit of  neuromodulation compared to placebo across (A) all test questions and (B) memory examination. [36]. 

Figure 8. (A) Nurosym neuromodulation compared to placebo significantly improved (*p < 0.05) across all test questions; (B) The effect was driven by a significant benefit (*p < 0.05) of Nurosym neuromodulation on memory questions. taVNS: Transcutaneous Vagus Nerve Stimulation [36].

Other research has demonstrated that therapy with the Nurosym device enhances performance on speed and decoding learning tasks in comparison to controls, signifying its potential for cognitive improvement (Figure 9) [37].

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Figure 9. Nurosym neuromodulation significantly (*p < 0.05) improved speed on the Automaticity and Decoding task compared to controls. Error bars represent standard error of the mean. taVNS: Transcutaneous Vagus Nerve Stimulation [37].

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Note: Ensure to consult healthcare professionals for accurate diagnosis and treatment. The information provided here is not a substitute for professional medical advice.

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[18] Babic and Browning. The role of vagal neurocircuits in the regulation of nausea and vomiting. Eur J Pharmacol 2014, 5;722:38-47. doi: 10.1016/j.ejphar.2013.08.047

[19] Loper, Leinen, et al. Both high fat and high carbohydrate diets impair vagus nerve signalling of satiety. Sci Rep 2021, 11:10394.

[20] Pavlov and Tracey. The vagus nerve and the inflammatory reflex-linking immunity and metabolism. Nat Rev Endocrinol, 2012, 8(12):743-54. doi: 10.1038/nrendo.2012.189

[21] Sorski and Gidron. The Vagal Nerve, Inflammation, and Diabetes-A Holy Triangle. Cells 2023, 12(12):1632. doi: 10.3390/cells12121632

[22] Zinglersen, Drange, et al. Vagus nerve stimulation as a novel treatment for systemic lupus erythematous: study protocol for a randomised, parallel-group, sham-controlled investigator-initiated clinical trial, the SLE-VNS study. BMJ Open 2022, 20;12(9):e064552. doi: 10.1136/bmjopen-2022-064552

[23] Kobrzycka, Napora, et al. Peripheral and central compensatory mechanisms for impaired vagus nerve function during peripheral immune activation. J Neuroinflammation 2019, 16: 150.

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[32] Parasym Clinical Trial, 2022;

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[37] Thakkar, Engelhart, et al. Transcutaneous auricular vagus nerve stimulation enhances learning of novel letter-sound relationships in adults. Brain Stimul 2020, 13(6):1813-1820. doi: 10.1016/j.brs.2020.10.012