TVNS and the Parasym

What is Transcutaneous Vagus Nerve Stimulation (TVNS) and how does the Parasym use it to reduce your tinnitus? 



tVNS reduces sympathetic activity and is therefore indicated in all conditions with sympathetic preponderance, such conditions include tinnitus associated with mental stress. The sympathetic nervous system is primarily involved with the fight or flight response, however it is constantly active at a basic level to maintain homeostasis. 



VNS was approved for pharmacoresistant epilepsy in EU in 1994 and in the US in 1997 (by the FDA- Food and Drug Administration).  Clinical observations of mood improvement in epilepsy patients after VNS implantation led studies which showed  that VNS has beneficial effects in depression. Subsequently, VNS–therapy was approved for treatment of depression both in EU (2001) and USA (2005).

The transcutaneous VNS has been demonstrated  to have similar effects in the vagal central pathways as VNS with Implanted electrodes (Kraus et al 2007 and 2013; Dietrich 2008; Polak et al  2009). In a prospective case series reduction in tinnitus/stress was demonstrated in patients who had suffered from moderate or severe tinnitus (Lehtimäki et al 2013 a and b). Stimulation was carried out in sessions of one hour each. Customized sound (music) therapy was applied simultaneously. Tinnitus loudness and annoyance (VAS), tinnitus handicap inventory (THI) and mini-TQ were registered before and after treatment. WHO-5-point questionnaire was used for the evaluation of general well-being, a. Heart rate was continuously monitored during the treatment sessions.

tVNS consistently reduced the subjective loudness and annoyance of tinnitus. The average scores of THI and mini-TQ were lowered by 20 and 5 points, respectively. Furthermore, tVNS seems to have a beneficial effect on tinnitus-related stress increasing significantly the patients coherence and subjective well-being. Heart rate monitoring during the tVNS treatments showed no cardiac or circulatory effects (e.g. bradycardia) in any of  the patients.

tVNS may offer an alternative treatment for patients with tinnitus In other clinical  studies tVNS has been demonstrated to have a good efficacy and safety in such disorders as depression (Hein et al 2012, Rong et al 2012), epilepsy (Stefan et al 2012), status asthmaticus (Steyn et al 2013), nausea (Napadow et al 2012).  Heart rate monitoring during the tVNS treatments have not shown any serious adverse effects (Kreuzer et al 2013, Lehtimäki et al 2013).  



The Parasym is a small device that delivers mild, intermittent pulsed electrical signals (microcurrents) through the skin of the patient’s left outer ear. The target of  this stimulation is the auricular branch of the vagus nerve. The stimulation is further transmitted to the brain, and various areas of the brain are activated (in the same way as shown to occur after VNS with implanted electrode).

VNS has been shown to induce widespread bilateral effects in areas of the brain implicated in seizures and mood disorders and responsible for modulation of key neurotransmitters such as serotonin and norepinephrine. Using an inbuilt adjustment system health professionals or the patients themselves can adjust the duration, frequency and intensity of stimulation.



No surgical risks, tVNS therapy with the Parasym provides targeted stimulation of the vagus nerve, without the risks of a surgical intervention.



Patients treat themselves with the Parasym in their familiar environment. The operation of the device is so simple that the Parasym can easily be integrated into the daily routine.


tVNS an approved therapy

Indications for VNS Therapy VNS (vagus nerve stimulation), therapy is EU and FDA approved as an adjunctive, long-term treatment for chronic or recurrent depression for patients 18 years of age or older who are experiencing a major depressive episode and have not had an adequate response to four or more adequate antidepressant treatments.

VNS Therapy was previously approved in EU 1994 and U.S.1997 as an adjunctive therapy for reducing the frequency of seizures in adults and adolescents over 12 years of age with partial-onset seizures which are refractory to antiepileptic medications. VNS Therapy System is also approved for sale in EU and US as a treatment for depression in patients with treatment-resistant or treatment intolerant major depressive episodes including unipolar depression and bipolar disorder (manic depression).



VNS Therapy is at various levels of investigational clinical studies as a potential treatment for various types of pain, nausea, sleep disorders, anxiety disorders, Alzheimer’s disease, bulimia and chronic headache/migraine, rheumatoid arthritis, Crohn´s disease, atrial fibrillation, congestive heart disease– and for many other symptoms and disorders.


Transcutaneous vagus nerve stimulation (tVNS) methodology 

The methodology of VNS used in epilepsy and depression is an invasive procedure. However, there exists an afferent sensory branch of the vagus nerve, which innervates the outer ear canal and parts of the auricle. This auricular branch of the vagus nerve (ABVN), projects centrally to the nucleus of the solitary tract in the brainstem. It was demonstrated by fMRI and EEG recordings that tVNS of ABVN activates the central vagal pathways similarly as implanted VNS. Therefore, the stimulation of ABVN might be an easy and noninvasive way to be used for patients to obtain the beneficial effects of vagal system activation. tVNS allows the stimulation of the vagus nerve without surgical procedure and the medial part of tragus and concha has been target for tVNS.  

It was recently demonstrated in the rat tinnitus model that tinnitus-related maladaptive neuronal plasticity (MNP) (=pathophysiological explanation for tinnitus) might be reversed by a combination of (implanted) VNS and sound stimulation. A clinical pilot study in tinnitus patients using implanted VNS paired with sound showed promising results as well. 

tVNS is a non-invasive, light and inexpensive new method of treating tinnitus and stress. Technology, research and quality engineering have made tVNS a safe and effective method of tinnitus relief.  One recent study shows that tVNS, if combined with sound therapy (ST), reduces the severity of tinnitus and tinnitus-associated distress. In the same study results of magnetoencephalography (MEG) showed that auditory cortical activation can be modulated by the application of tVNS (Lehtimäki et al, Acta Otolaryngol  2013). Thus, tVNS seems offer a new avenue to treat tinnitus and tinnitus-associated distress. This distress, as measured by heart rate variability (HRV)-test was demonstrated to diminish in the great majority patients with tinnitus-associated stress reaction.


What conditions can be treated with the Parasym

Parasym can be used to provide relief from tinnitus and mood disorders As Parasym is a new way of activating the parasympathetic nervous system, it can be used in a large number of illnesses in which there is a dysfunction of the autonomous nervous system with sympathetic preponderance.


Advantages of  Parasym

Use of tVNS has a number of advantages: Foremost it is safe. Efficacy for tinnitus usually takes weeks or months but many people feel immediate stress relief. It is drug-free, non-addictive and non-invasive. It is user friendly, portable and ideal for home use.  


Theoretic background and stimulation parameters

Transcutaneous Vagus Nerve Stimulation (tVNS) uses the fact that the auricular branch of the vagus nerve (ABVN) supplies the skin of the outer meatus in the human ear. This allows for transcutaneous electrical stimulation of the nerve fibers in this area. Intensity, pulse duration and frequency of the tVNS stimulation have been optimised to induce signals in thick-myelinated Aβ fibres of the ABVN*. 

Like those of the cervical branch of the vagus nerve, these project directly to the nucleus of the solitary tract (NTS) in the brainstem. The NTS is the starting point to activate a complex cerebral network, corresponding closely to that targeted by invasive VNS, and associated with the anti-convulsive effect. 


*Minor Side effects-tVNS with Parasym is a therapeutic alternative with minor side effects. An analysis of data from over 120 patients and volunteers, who participated in studies of tVNS, showed potential side effects including, dysaesthesia (abnormal sensation), mild itching and minor local pain at the stimulation site. These side effects disappear after removing the electrode.



Kraus T, Hösl K, Kiess O, Schanze A, Kornhuber J, Forster C. BOLD fMRI deactivation of limbic and temporal brain structures and mood enhancing effect by transcutaneous vagus nerve stimulation. J  Neural Transm 2007; 114:1485-93. 

Kraus T, Kiess O, Hösl K, Terekhin P, Kornhuber J, Forster C. CNS BOLD fMRI effects of sham-controlled transcutaneous electrical nerve stimulation in the left outer auditory canal - A pilot study. Brain Stimul. 2013 Feb 13. 

Dietrich S, Smith J, Scherzinger C et al. A novel transcutaneous vagus nerve stimulation leads to brainstem and cerebral activations measured by functional MRI. Biomed Tech 2008; 53:104-11. 

Polak T, Markulin F, Ehlis AC, Langer JB, Ringel TM, Fallgatter AJ. Far field potentials from brain stem after transcutaneous vagus nerve stimulation: optimization of stimulation and recording parameters J Neural Transm 2009;116:1237-42. 

Santeri Yrttiaho, Mikael Bergholm, Kari Malkavaara, Jarmo Lehtimäki, Jukka Ylikoski: Transcutaneous Vagus Nerve Stimulation 

(tVNS) Attenuates Auditory Cortical Responsiveness in Tinnitus Patients. Abstract American Research in Otolaryngology, San Diego, CA, Feb 20-24, 2012 

Lehtimäki J, Hyvärinen P, Ylikoski M, Bergholm M, Mäkelä JP, Aarnisalo A, Pirvola U, Mäkitie A, Ylikoski J. Transcutaneous vagus nerve stimulation in tinnitus: a pilot study. Acta Otolaryngol. 2013 Apr;133(4):378-82

Lehtimäki J, Ylikoski M, Pirvola U, Aarnisalo A, Mäkitie A , Ylikoski J. Efficacy and safety of Transcutaneous Vagus Nerve 

Stimulation in Tinnitus.  Abstract. 7th International Tinnitus Research Initative Meeting, Valencia, Spain, May 15- 18, 2013




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