title: Non-invasive vagus nerve stimulation reduces sympathetic preponderance in patients with tinnitus.
abstract: CONCLUSIONS
  Transcutaneous vagal nerve stimulation (tVNS) might offer a targeted, patient-friendly, and low-cost therapeutic tool for tinnitus patients with sympathovagal imbalance.
  
  
  OBJECTIVE
  Conventionally, VNS has been performed to treat severe epilepsy and depression with an electrode implanted to the cervical trunk of vagus nerve. This study investigated the acute effects of tVNS on autonomic nervous system (ANS) imbalance, which often occurs in patients with tinnitus-triggered stress.
  
  
  METHODS
  This study retrospectively analysed records of 97 patients who had undergone ANS function testing by heart rate variability (HRV) measurement immediately before and after a 15-60 min tVNS stimulation.
  
  
  RESULTS
  The pre-treatment HRV recording showed sympathetic preponderance/reduced parasympathetic activity in about three quarters (73%) of patients. Active tVNS significantly increased variability of R-R intervals in 75% of patients and HRV age was decreased in 70% of patients. Either the variability of R-R intervals was increased or the HRV age decreased in 90% of the patients. These results indicate that tVNS can induce a shift in ANS function from sympathetic preponderance towards parasympathetic predominance. tVNS caused no major morbidity, and heart rate monitoring during the tVNS treatment showed no cardiac or circulatory effects (e.g. bradycardia) in any of the patients.
authors.affiliation: a Helsinki Ear Institute , Helsinki , Finland.|b Vagus Medical Inc , Helsinki , Finland.
authors.forename: Jukka
authors.initials: J
authors.lastname: Ylikoski
authors.affiliation: a Helsinki Ear Institute , Helsinki , Finland.|b Vagus Medical Inc , Helsinki , Finland.
authors.forename: Jarmo
authors.initials: J
authors.lastname: Lehtimäki
authors.affiliation: c Department of Biosciences , University of Helsinki , Helsinki , Finland.
authors.forename: Ulla
authors.initials: U
authors.lastname: Pirvola
authors.affiliation: d Department of Otolaryngology - Head and Neck Surgery , University of Helsinki and Helsinki University Hospital , Helsinki , Finland.
authors.forename: Antti
authors.initials: A
authors.lastname: Mäkitie
authors.affiliation: d Department of Otolaryngology - Head and Neck Surgery , University of Helsinki and Helsinki University Hospital , Helsinki , Finland.
authors.forename: Antti
authors.initials: A
authors.lastname: Aarnisalo
authors.affiliation: d Department of Otolaryngology - Head and Neck Surgery , University of Helsinki and Helsinki University Hospital , Helsinki , Finland.
authors.forename: Petteri
authors.initials: P
authors.lastname: Hyvärinen
authors.affiliation: a Helsinki Ear Institute , Helsinki , Finland.|b Vagus Medical Inc , Helsinki , Finland.
authors.forename: Matti
authors.initials: M
authors.lastname: Ylikoski
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013564:Sympathetic Nervous System / Q000503:physiopathology*; D014012:Tinnitus / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D055536:Vagus Nerve Stimulation; D055815:Young Adult
keywords: Stress; autonomic nervous system; heart rate variability; tinnitus; vagal nerve