Transcutaneous Vagus Nerve Stimulation

 

VNS Device

 

Ear Clip Electrode

Depression

treatment

OVERVIEW

 

We are investigating into the treatment of Depression using Transcutaneous Vagus Nerve Stimulation, a non-invasive alternative treatment.

Research suggests that stimulating the Vagus Nerve is a promising, safe and cost effective therapeutic method for mild and moderate depression.  

Non-invasive vagus nerve stimulation

 

The Parasym device non-invasively stimulates the Vagus Nerve.

 

This is done using a specially designed unit and ear-clip electrode.

 

Small micro-pulses of electricity are sent from the device to the Vagus Nerve, through the electrode.

Research 

On the treatment of depression using Vagus Nerve Stimulation

 

autonomic nervous system

 

Parasympathetic and Sympathetic

 

Nemeroff, C. B., Mayberg, H. S., Krahl, S. E., McNamara, J., Frazer, A., Henry, T. R., ... & Brannan, S. K. (2006). VNS therapy in treatment-resistant depression: clinical evidence and putative neurobiological mechanisms. Neuropsychopharmacology, 31(7), 1345-1355.

 

Kraus, T., Hösl, K., Kiess, O., Schanze, A., Kornhuber, J., & Forster, C. (2007). BOLD fMRI deactivation of limbic and temporal brain structures and mood enhancing effect by transcutaneous vagus nerve stimulation. Journal of neural transmission, 114(11), 1485-1493.

 

“tVNS fMRI in healthy volunteers - Increased well being and hypoactivity (decrease)  in brain areas associated with anxiety and depression”

 

Nahas, Z., Marangell, L. B., Husain, M. M., Rush, A. J., Sackeim, H. A., Lisanby, S. H., ... & George, M. S. (2005). Two-year outcome of vagus nerve stimulation (VNS) for treatment of major depressive episodes. The Journal of clinical psychiatry, 66(9), 1-478.

 

“HAM-D-28 response rates were 31% (18/59) after 3 months, 44% (26/59) after 1 year of adjunctive VNS. Remission rates were 15% (9/59) at 3 months, 27% (16/59) at 1 year”

 

George, M. S., Sackeim, H. A., Rush, A. J., Marangell, L. B., Nahas, Z., Husain, M. M., ... & Ballenger, J. C. (2000). Vagus nerve stimulation: a new tool for brain research and therapy∗. Biological psychiatry, 47(4), 287-295.

 

Schlaepfer, T. E., Frick, C., Zobel, A., Maier, W., Heuser, I., Bajbouj, M., ... & Rau, H. (2008). Vagus nerve stimulation for depression: efficacy and safety in a European study. Psychological medicine, 38(05), 651-661.

 

“The baseline 28-item Hamilton Depression Rating Scale (HAMD-28) score averaged 34. After 3 months of VNS, response rates (>= 50% reduction in baseline scores) reached 37% and remission rates (HAMD-28 score <10) 17%. Response rates increased to 53% after 1 year of VNS, and remission rates reached 33%. Response was defined as sustained if no relapse occurred during the first year of VNS after response onset; 44% of patients met these criteria. Median time to response was 9 months.”

 

Zobel, A., Joe, A., Freymann, N., Clusmann, H., Schramm, J., Reinhardt, M., ... & Broich, K. (2005). Changes in regional cerebral blood flow by therapeutic vagus nerve stimulation in depression: an exploratory approach. Psychiatry Research: Neuroimaging, 139(3), 165-179.

 

“Abnormalities in regional cerebral blood flow (rCBF) have been reported to characterize depressive episodes; they are at least partly reversed by antidepressant treatment. We explored the changes in rCBF induced by vagus nerve stimulation (VNS), a recently proposed antidepressant strategy. Decreases of rCBF in the amygdala, left hippocampus, left subgenual cingulate cortex, left and right ventral anterior cingulum, right thalamus and brain stem were observed; the only increase of rCBF was found by SPM analysis in the middle frontal gyrus. This pattern shares features with changes of rCBF previously associated with the administration of selective serotonin reuptake inhibitors. Similarities to other brain-stimulation strategies in antidepressant treatment were less pronounced.”

 

Sackeim, H. A., Keilp, J. G., Rush, A. J., George, M. S., Marangell, L. B., Dormer, J. S., ... & Oliver, N. (2001). The effects of vagus nerve stimulation on cognitive performance in patients with treatment-resistant depression.Cognitive and Behavioral Neurology, 14(1), 53-62.

 

Das, U. N. (2007). Vagus nerve stimulation, depression, and inflammation.Neuropsychopharmacology, 32(9), 2053-2054.

 

“Proinflammatory cytokines may cause depressive illness”

 

Sackeim, H. A., Rush, A. J., George, M. S., Marangell, L. B., Husain, M. M., Nahas, Z., ... & Simpson, R. K. (2001). Vagus nerve stimulation (VNS™) for treatment-resistant depression: efficacy, side effects, and predictors of outcome. Neuropsychopharmacology,

 

Rush, A. J., Marangell, L. B., Sackeim, H. A., George, M. S., Brannan, S. K., Davis, S. M., ... & Rapaport, M. H. (2005). Vagus nerve stimulation for treatment-resistant depression: a randomized, controlled acute phase trial.Biological psychiatry,  (non-support)

 

George, M. S., Rush, A. J., Marangell, L. B., Sackeim, H. A., Brannan, S. K., Davis, S. M., ... & Dunner, D. (2005). A one-year comparison of vagus nerve stimulation with treatment as usual for treatment-resistant depression. Biological psychiatry, 58(5), 364-373.

 

“The response rate was sustained [40% (12/30) to 46% (13/28); p = .317] and the remission rate significantly increased [17% (5/30) to 29% (8/28); p = .045] with an additional 9 months of long-term vagus nerve stimulation treatment after exit from the acute study (1 year total vagus nerve stimulation treatment). Significant improvements in function between acute study exit and the 1-year follow-up assessment as measured by the Medical Outcomes Study Short Form-36 were observed.”

 

Rush, A. J., Sackeim, H. A., Marangell, L. B., George, M. S., Brannan, S. K., Davis, S. M., ... & Carpenter, L. (2005). Effects of 12 months of vagus nerve stimulation in treatment-resistant depression: a naturalistic study. Biological psychiatry, (some support)

 

Bajbouj, M., Merkl, A., Schlaepfer, T. E., Frick, C., Zobel, A., Maier, W., ... & Rau, H. (2010). Two-year outcome of vagus nerve stimulation in treatment-resistant depression. Journal of clinical psychopharmacology,  (some support)

 

Schlaepfer, T. E., Frick, C., Zobel, A., Maier, W., Heuser, I., Bajbouj, M., ... & Rau, H. (2008). Vagus nerve stimulation for depression: efficacy and safety in a European study. Psychological medicine, (Supportive)

 

George, M. S., Rush, A. J., Sackeim, H. A., & Marangell, L. B. (2003). Vagus nerve stimulation (VNS): utility in neuropsychiatric disorders. The International Journal of Neuropsychopharmacology,

 

"Regions of blood flow change were consistent with brain structures associated with depression and the afferent pathways of the vagus nerve."

 

Conway, C. R., Sheline, Y. I., Chibnall, J. T., George, M. S., Fletcher, J. W., & Mintun, M. A. (2006). Cerebral blood flow changes during vagus nerve stimulation for depression. Psychiatry Research: Neuroimaging

 

Zobel, A., Joe, A., Freymann, N., Clusmann, H., Schramm, J., Reinhardt, M., ... & Broich, K. (2005). Changes in regional cerebral blood flow by therapeutic vagus nerve stimulation in depression: an exploratory approach. Psychiatry Research: Neuroimaging,

 

Nahas, Z., Teneback, C., Chae, J. H., Mu, Q., Molnar, C., Kozel, F. A., ... & Lomarev, M. (2007). Serial vagus nerve stimulation functional MRI in treatment-resistant depression. Neuropsychopharmacology,

 

Milby, A. H., Halpern, C. H., & Baltuch, G. H. (2008). Vagus nerve stimulation for epilepsy and depression. Neurotherapeutics,

 

Nierenberg, A. A., Alpert, J. E., Gardner-Schuster, E. E., Seay, S., & Mischoulon, D. (2008). Vagus nerve stimulation: 2-year outcomes for bipolar versus unipolar treatment-resistant depression. Biological psychiatry,

 

Bodenlos, J. S., Kose, S., Borckardt, J. J., Nahas, Z., Shaw, D., O’Neil, P. M., & George, M. S. (2007). Vagus nerve stimulation acutely alters food craving in adults with depression. Appetite,

 

 

HPA Axis

 

O’Keane, V., Dinan, T. G., Scott, L., & Corcoran, C. (2005). Changes in hypothalamic–pituitary–adrenal axis measures after vagus nerve stimulation therapy in chronic depression. Biological psychiatry,

 

Corcoran, C. D., Thomas, P., Phillips, J., & O'Keane, V. (2006). Vagus nerve stimulation in chronic treatment-resistant depression. The British Journal of Psychiatry, (support - side effects -related to invasive)

 

Goodnick, P. J., Rush, A. J., George, M. S., Marangell, L. B., & Sackeim, H. A. (2001). Vagus nerve stimulation in depression. Expert opinion on pharmacotherapy,

 

Cristancho, P., Cristancho, M. A., Baltuch, G. H., Thase, M. E., & O’Reardon, J. P. (2011). Effectiveness and safety of vagus nerve stimulation for severe treatment-resistant major depression in clinical practice after FDA approval: outcomes at 1 year. The Journal of clinical psychiatry,

 

Labiner, D. M., & Ahern, G. L. (2007). Vagus nerve stimulation therapy in depression and epilepsy: therapeutic parameter settings. Acta neurologica scandinavica

 

 

VNS may change the encoding of negative memories

 

Critchley, H. D., Lewis, P. A., Orth, M., Josephs, O., Deichmann, R., Trimble, M. R., & Dolan, R. J. (2007). Vagus nerve stimulation for treatment-resistant depression: behavioural and neural effects on encoding negative material.Psychosomatic medicine,

 

Pardo, J. V., Sheikh, S. A., Schwindt, G. C., Lee, J. T., Kuskowski, M. A., Surerus, C., ... & Rittberg, B. R. (2008). Chronic vagus nerve stimulation for treatment-resistant depression decreases resting ventromedial prefrontal glucose metabolism. Neuroimage,  (non support)

 

Kosel, M., Brockmann, H., Frick, C., Zobel, A., & Schlaepfer, T. E. (2011). Chronic vagus nerve stimulation for treatment-resistant depression increases regional cerebral blood flow in the dorsolateral prefrontal cortex. Psychiatry Research: Neuroimaging,

 

Rush, A. J., & Siefert, S. E. (2009). Clinical issues in considering vagus nerve stimulation for treatment-resistant depression. Experimental neurology, (Support)

 

George, M. S., Nahas, Z., Borckardt, J. J., Anderson, B., Burns, C., Kose, S., & Short, E. B. (2007). Vagus nerve stimulation for the treatment of depression and other neuropsychiatric disorders. Expert review of neurotherapeutics,

 

Shafique, S., & Dalsing, M. C. (2006). Vagus nerve stimulation therapy for treatment of drug-resistant epilepsy and depression. Perspectives in vascular surgery and endovascular therapy,

 

Aaronson, S. T., Carpenter, L. L., Conway, C. R., Reimherr, F. W., Lisanby, S. H., Schwartz, T. L., ... & Husain, M. (2013). Vagus nerve stimulation therapy randomized to different amounts of electrical charge for treatment-resistant depression: acute and chronic effects. Brain stimulation,

 

O'Reardon, J. P., Cristancho, P., & Peshek, A. D. (2006). Vagus nerve stimulation (VNS) and treatment of depression: to the brainstem and beyond.Psychiatry (Edgmont),

 

Armitage, R., Husain, M., Hoffmann, R., & Rush, A. J. (2003). The effects of vagus nerve stimulation on sleep EEG in depression: a preliminary report.Journal of psychosomatic research,

 

“VNS improved the clinical symptoms of depression and sleep architecture. Results suggest that treatment-resistant depressed patients have dampened sleep EEG rhythms that are restored to near-normal amplitudes with VNS treatment.”

 

Mohr, P., Rodriguez, M., Slavíčková, A., & Hanka, J. (2011). The application of vagus nerve stimulation and deep brain stimulation in depression.Neuropsychobiology,

 

Berry, S. M., Broglio, K., Bunker, M., Jayewardene, A., Olin, B., & Rush, A. J. (2013). A patient-level meta-analysis of studies evaluating vagus nerve stimulation therapy for treatment-resistant depression. Med Devices (Auckl),

 

“For patients with chronic Treatment Resistant Depression, VNS + TAU (Treatment As Usual) has greater response and remission rates that are more likely to persist than TAU.”

 

 

Pregnancy (with VNS - A Case Report)

 

Husain, M. M., Stegman, D., & Trevino, K. (2005). Pregnancy and delivery while receiving vagus nerve stimulation for the treatment of major depression: a case report. Annals of general psychiatry,

 

MATTHEWS, K., & ELJAMEL, M. S. (2003). Vagus nerve stimulation and refractory depression. The British Journal of Psychiatry,

 

Park, M. C., Goldman, M. A., Carpenter, L. L., Price, L. H., & Friehs, G. M. (2007). Vagus nerve stimulation for depression: rationale, anatomical and physiological basis of efficacy and future prospects. In Operative Neuromodulation

 

Grimm, S., & Bajbouj, M. (2010). Efficacy of vagus nerve stimulation in the treatment of depression. Expert review of neurotherapeutics,

 

Conway, C. R., Chibnall, J. T., Gangwani, S., Mintun, M. A., Price, J. L., Hershey, T., ... & Sheline, Y. I. (2012). Pretreatment cerebral metabolic activity correlates with antidepressant efficacy of vagus nerve stimulation in treatment-resistant major depression: a potential marker for response?.Journal of affective disorders,

 

Martinez, J. M., & Zboyan, H. A. (2006). Vagus nerve stimulation therapy in a patient with treatment-resistant depression: a case report of long-term follow-up and battery end-of-service. CNS spectrums,

 

Conway, C. R., Chibnall, J. T., Gebara, M. A., Price, J. L., Snyder, A. Z., Mintun, M. A., ... & Sheline, Y. I. (2013). Association of cerebral metabolic activity changes with vagus nerve stimulation antidepressant response in treatment-resistant depression. Brain stimulation,

 

Sperling, W., Reulbach, U., Bleich, S., Padberg, F., Kornhuber, J., & Mueck-Weymann, M. (2010). Cardiac effects of vagus nerve stimulation in patients with major depression. Pharmacopsychiatry,

 

Sperling, W., Reulbach, U., & Kornhuber, J. (2009). Clinical benefits and cost effectiveness of vagus nerve stimulation in a long-term treatment of patients with major depression.

 

RESULTS:

Compared with baseline values in the HAMD scale (mean 23.7; SD 2.4), there was a significant (t=14.5; df=8; p<0.001) improvement in symptoms after 12 months' stimulation (mean 10.2; SD 2.4). The duration of hospitalisation dropped on average by 20 days in the first post-implantation year, the treatment frequency from 33 to 14 visits, and drug treatment from 4 to an average of 3 psychotropic drugs.

CONCLUSION:

In addition to an improvement in clinical symptoms, the VNS method might enable an amortisation of costs.

 

Bajbouj, M., Gallinat, J., Lang, U. E., Hellen, F., Vesper, J., Lisanby, S. H., ... & Neu, P. (2007). Motor cortex excitability after vagus nerve stimulation in major depression. Journal of clinical psychopharmacology,

 

Conway, C. R., Chibnall, J. T., & Tait, R. C. (2008). Vagus nerve stimulation for depression: a case of a broken lead, depression relapse, revision surgery, and restoration of patient response. Brain stimulation,

 

Panescu, D. (2005). Vagus nerve stimulation for the treatment of depression.IEEE engineering in medicine and biology magazine,

 

 

Large Cost Savings with VNS

 

Cohen, L. J., & Allen Jr, J. C. (2008). Estimating the potential savings with vagus nerve stimulation for treatment-resistant depression: a payer perspective. Current medical research and opinion,

 

Dell’Osso, B., Oldani, L., Palazzo, M. C., Balossi, I., Ciabatti, M., & Altamura, A. C. (2013). Vagus nerve stimulation in treatment-resistant depression: Acute and follow-up results of an italian case series. The journal of

 

Sperling, W., Reulbach, U., Maihöfner, C., Kornhuber, J., & Bleich, S. (2008). Vagus nerve stimulation in a patient with Gilles de la Tourette syndrome and major depression. Pharmacopsychiatry,

 

Yu, Z. J., Weller, R. A., Sandidge, K., & Weller, E. B. (2008). Vagus nerve stimulation: Can it be used in adolescents or children with treatment-resistant depression?. Current psychiatry reports,

 

Müller, H. H., Kornhuber, J., Maler, J. M., & Sperling, W. (2013). The effects of stimulation parameters on clinical outcomes in patients with vagus nerve stimulation implants with major depression. The journal of ECT,

 

Patel, A. R., & Wozniak, S. M. (2007). Improved mood and remission of symptoms in long-term major depression using vagus nerve stimulation.Medscape General Medicine,

 

Marangell, L. B., Martinez, M., Martinez, J. M., George, M. S., & Sackeim, H. A. (2005). Blog Archives Vagus Nerve Stimulation: A New Tool for Treating Depression. Primary psychiatry,

 

Chen, S. P., Ay, I., de Morais, A. L., Qin, T., Zheng, Y., Sadeghian, H., ... & Ayata, C. (2016). Vagus nerve stimulation inhibits cortical spreading depression. Pain,

 

Both noninvasive transcutaneous and invasive direct vagus nerve stimulations significantly suppressed spreading depression susceptibility in the occipital cortex in rats. The electrical stimulation threshold to evoke a spreading depression was elevated by more than 2-fold, the frequency of spreading depressions during continuous topical 1 M KCl was reduced by ∼40%, and propagation speed of spreading depression was reduced by ∼15%. This effect developed within 30 minutes after vagus nerve stimulation and persisted for more than 3 hours. Noninvasive transcutaneous vagus nerve stimulation was as efficacious as direct invasive vagus nerve stimulation, and the efficacy did not differ between the ipsilateral and contralateral hemispheres. Our findings provide a potential mechanism by which vagus nerve stimulation may be efficacious in migraine and suggest that susceptibility to spreading depression is a suitable platform to optimize its efficacy.

 

Yuan, W., & Williams, B. N. (2012). Long-term vagus nerve stimulation for severe refractory depression: a case study with a six-year follow-up. The Journal of neuropsychiatry and clinical neurosciences,

 

Yuan, T. F., Li, A., Sun, X., Arias-Carrión, O., & Machado, S. (2016). Vagus nerve stimulation in treating depression: A tale of two stories. Current molecular medicine,

 

Tisi, G., Franzini, A., Messina, G., Savino, M., & Gambini, O. (2014). Vagus nerve stimulation therapy in treatment‐resistant depression: A series report.Psychiatry and clinical neurosciences,

 

Oldani, L., Dell'Osso, B., & Altamura, A. C. (2015). Long-term Effects of Vagus Nerve Stimulation in Treatment-resistant Depression: A 5-year Follow up Case Series. Brain stimulation,

 

Nahas, Z. (2003). Is Vagus Nerve Stimulation the Next Breakthrough for Treatment-Resistant Depression?. Psychiatric Times,

 

Merkl, A., Brakemeier, E. L., Danker-Hopfe, H., & Bajbouj, M. (2007). Vagus nerve stimulation improves restless legs syndrome associated with major depression: A case report. The Journal of clinical psychiatry,

 

Tulgar, M., Ozan, E., & Akan, Z. (2015). Vagus Nerve Stimulation for the management of depression: Rationale, anatomical and physiological basis of efficacy and future prospects. Natural Science and Discovery,

 

De Ridder, D., Kilgard, M., Engineer, N., & Vanneste, S. (2015). Placebo-controlled vagus nerve stimulation paired with tones in a patient with refractory tinnitus: a case report. Otology & Neurotology, 36(4), 575-580.

 

 

Non-Invasive

 

Fang, J., Rong, P., Hong, Y., Fan, Y., Liu, J., Wang, H., ... & Liu, R. (2016). Transcutaneous vagus nerve stimulation modulates default mode network in major depressive disorder. Biological psychiatry,

 

Rong, P., Liu, J., Wang, L., Liu, R., Fang, J., Zhao, J., ... & Ben, H. (2016). Effect of transcutaneous auricular vagus nerve stimulation on major depressive disorder: A nonrandomized controlled pilot study. Journal of affective disorders,

 

Ben‐Menachem, E., Revesz, D., Simon, B. J., & Silberstein, S. (2015). Surgically implanted and non‐invasive vagus nerve stimulation: a review of efficacy, safety and tolerability. European Journal of Neurology,

 

Capone, F., Assenza, G., Di Pino, G., Musumeci, G., Ranieri, F., Florio, L., ... & Di Lazzaro, V. (2015). The effect of transcutaneous vagus nerve stimulation on cortical excitability. Journal of Neural Transmission,

 

“Our findings confirm that tVNS is a safe and effective way to stimulate vagus nerve”

 

Inoue, T., Abe, C., Sun-sang, J. S., Moscalu, S., Jankowski, J., Huang, L., ... & Okusa, M. D. (2016). Vagus nerve stimulation mediates protection from kidney ischemia-reperfusion injury through α7nAChR+ splenocytes. The Journal of clinical investigation,

 

Rong, P., Liu, J., Wang, L., Liu, R., Fang, J., Zhao, J., ... & Ben, H. (2016). Effect of transcutaneous auricular vagus nerve stimulation on major depressive disorder: A nonrandomized controlled pilot study. Journal of affective disorders,

 

Trevizol, A. P., Taiar, I., Barros, M. D., Liquidatto, B., Cordeiro, Q., & Shiozawa, P. (2015). Transcutaneous vagus nerve stimulation (tVNS) protocol for the treatment of major depressive disorder: A case study assessing the auricular branch of the vagus nerve. Epilepsy & Behavior,

 

Rong, P. J., Fang, J. L., Wang, L. P., Meng, H., Liu, J., Ma, Y. G., ... & Zhao, Y. F. (2012). Transcutaneous vagus nerve stimulation for the treatment of depression: a study protocol for a double blinded randomized clinical trial.BMC complementary and alternative medicine,   (no results)

 

Rong, P. (2014). AN ALTERNATIVE THERAPY FOR DEPRESSION: TRANSCUTANEOUS AURICULAR VAGUS NERVE STIMULATION. Journal of Integrative Medicine

 

Clancy, J. A., Mary, D. A., Witte, K. K., Greenwood, J. P., Deuchars, S. A., & Deuchars, J. (2014). Non-invasive vagus nerve stimulation in healthy humans reduces sympathetic nerve activity. Brain stimulation,

 

Hein, E., Nowak, M., Kiess, O., Biermann, T., Bayerlein, K., Kornhuber, J., & Kraus, T. (2013). Auricular transcutaneous electrical nerve stimulation in depressed patients: a randomized controlled pilot study. Journal of Neural Transmission,

 

Frangos, E., Ellrich, J., & Komisaruk, B. R. (2015). Non-invasive access to the vagus nerve central projections via electrical stimulation of the external ear: fMRI evidence in humans. Brain stimulation,

 

“central projections of the ABVN are consistent with the “classical” central vagal projections and can be accessed non-invasively via the external ear.”

 

Kinfe, T. M., Pintea, B., Muhammad, S., Zaremba, S., Roeske, S., Simon, B. J., & Vatter, H. (2015). Cervical non-invasive vagus nerve stimulation (nVNS) for preventive and acute treatment of episodic and chronic migraine and migraine-associated sleep disturbance: preliminary findings from a prospective observational cohort study. The journal of headache and pain,

 

Kreuzer, P. M., Landgrebe, M., Husser, O., Resch, M., Schecklmann, M., Geisreiter, F., ... & Langguth, B. (2012). Transcutaneous vagus nerve stimulation: retrospective assessment of cardiac safety in a pilot study.Frontiers in psychiatry,

 

Clancy, J. A., Mary, D. A., Witte, K. K., Greenwood, J. P., Deuchars, S. A., & Deuchars, J. (2014). Non-invasive vagus nerve stimulation in healthy humans reduces sympathetic nerve activity. Brain stimulation,

 

Shiozawa, P., Silva, M. E. D., Carvalho, T. C. D., Cordeiro, Q., Brunoni, A. R., & Fregni, F. (2014). Transcutaneous vagus and trigeminal nerve stimulation for neuropsychiatric disorders: a systematic review. Arquivos de neuro-psiquiatria,

 

literature 

 

Our autonomic nervous system (ANS) is a control system that acts largely unconsciously and is responsible for the regulation many of our bodily functions. Is has two branches that work in opposition to one another to create a balance, these are the parasympathetic nervous system and the sympathetic nervous system.

 

The sympathetic nervous system is often considered the 'fight or flight' system, while the parasympathetic is referred to as the 'rest and digest' system. Many serious health conditions have been linked to an overactive sympathetic nervous system (high stress), where the ANS is out of balance.  

 

The vagus nerve is linked to the parasympathetic branch of the ANS and by stimulating it, it is possible to reduce sympathetic activity and restore natural balance in the body needed for optimal health. 

Parasym

HEALTH