Below is a list of clinical trials and scientific research into the use of Vagus Nerve Stimulation and Sound Therapy in the treatment of Tinnitus.
Note: The Parasym device was formerly the SaluStim device.
Helsinki Ear Institute study showing that tVNS can effectively be used to treat Tinnitus if paired with tailored sound therapy.
Lehtimäki, J., Hyvärinen, P., Ylikoski, M., Bergholm, M., Mäkelä, J. P., Aarnisalo, A., ... & Ylikoski, J. (2013). Transcutaneous vagus nerve stimulation in tinnitus: a pilot study. Acta oto-laryngologica, 133(4), 378-382.
The Sixth International Conference on Tinnitus referencing tVNS and Combined Sound therapy as a viable method for treating Tinnitus
‘How to Stop tinnitus by buzzing the vagus’
An observed reversal of the pathological neural activity observed in tinnitus, through VNS and sound therapy
Engineer, N. D., Riley, J. R., Seale, J. D., Vrana, W. A., Shetake, J. A., Sudanagunta, S. P., ... & Kilgard, M. P. (2011). Reversing pathological neural activity using targeted plasticity. Nature, 470(7332), 101-104.
Medical Science College of China and Yichang TCM Hospital study, showing the positive effects of tVNS treatment when used in conjunction with sound therapy
MEI, Z. G., YANG, S. B., CAI, S. J., LEI, H. P., Chuang, Z. H. O. U., Guo, Y. H., & ZHANG, D. Q. (2014). Treatment of tinnitus with electrical stimulation on acupoint in the distribution area of ear vagus nerve combining with sound masking: randomized controlled trial. World Journal of Acupuncture-Moxibustion, 24(2), 30-35.
tVNS can interfere with tinnitus related neural activity patterns, such as cortical gamma rhythms, causing reductions in tinnitus.
Hyvärinen, P., Yrttiaho, S., Lehtimäki, J., Ilmoniemi, R. J., Mäkitie, A., Ylikoski, J., ... & Aarnisalo, A. A. (2015). Transcutaneous vagus nerve stimulation modulates tinnitus-related Beta-and gamma-band activity. Ear and hearing,36(3), e76.
German study illustrating the therapeutic effects of tVNS for the treatment of chronic tinnitus
Geisreiter, F. (2015). Transkutane nicht-invasive Vagusnervstimulation zur Behandlung von chronischem Tinnitus (Doctoral dissertation).[English: Transcutaneous Vagus Nerve Stimulation noninvasive to treat chronic tinnitus]
Non-invasive VNS can reduce sympathetic nerve activity (Fight or flight response, linked with negative association in Tinnitus)
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, 7(6), 871-877.
Mood Enhancement and deactivation of the limbic system through tVNS
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.
Non-invasive stimulation of the Vagus Nerve has effects consistent with that of ‘Classical’ Invasive stimulation through implanted electrodes.
Frangos, E., Ellrich, J., & Komisaruk, B. R. (2014). Non-invasive access to the vagus nerve central projections via electrical stimulation of the external ear: fMRI evidence in humans. Brain stimulation.
Only minor and often resolvable side effects of treatment seen from over 10,000 patients over a 12 year period. Note: this paper is referring to invasive VNS (Implanted electrode)
No Major Contraindications were found with the treatment of Tinnitus through tVNS
Kreuzer, P. M., Landgrebe, M., Husser, O., Resch, M., Schecklmann, M., Geisreiter, F., ... & Langguth, B. (2011). Transcutaneous vagus nerve stimulation: retrospective assessment of cardiac safety in a pilot study.Frontiers in psychiatry, 3, 70-70.
VNS paired with tones excluding the tinnitus-matched frequency is safe and feasible. It seems to exert a beneficial effect in non-medication-taking patients, both with regard to the perceived sound and the distress.
De Ridder, D., Vanneste, S., Engineer, N. D., & Kilgard, M. P. (2014). Safety and efficacy of vagus nerve stimulation paired with tones for the treatment of tinnitus: a case series. Neuromodulation: Technology at the Neural Interface,17(2), 170-179.
tVNS device can safely and easily be applied to patients for clinical application
The method of tVNS and device are both feasible and appropriate for accessing cerebral vagus nerve structures
Dietrich, S., Smith, J., Scherzinger, C., Hofmann-Preiss, K., Freitag, T., Eisenkolb, A., & Ringler, R. (2008). A novel transcutaneous vagus nerve stimulation leads to brainstem and cerebral activations measured by functional MRI. Biomedizinische Technik. Biomedical engineering, 53(3), 104-111.
tVNS does not appear to impact pupillary light reflex
Huber D, Fischenich A, Wolf N, Ellrich J (Poster) Transcutaneous vagus nerve stimulation has no impact on the pupillary light reflex in healthy volunteers. SfN's 42nd annual meeting of the Society for Neuroscience, New Orleans, 2012
fMRI study on non-invasive tVNS
Ringler R, Fischenich A, Scherzinger C, Hartlep A, Dietrich S (Poster) BOLD fMRI clusters during transcutaneous vagus nerve stimulation (t-VNS) vary with frequency and pulse width. 39th Annual Meeting of the Society for Neuroscience, Chicago, 2009
Additional Benefits of tVNS
Overview of the clinical applications of Vagus Nerve Stimulation
The Vagus (Latin for Wanderer) nerve is linked to many parts of the body and stimulation could be beneficial in many other conditions, including heart failure, tinnitus, Depression, chronic hiccups, Alzheimer's disease and inflammatory diseases
Vagus nerve stimulation can efficiently modulate pain processing through nociception
tVNS for the treatment of drug resistant epilepsy