title: The effect of transcutaneous vagus nerve stimulation on pain perception--an experimental study.
abstract: BACKGROUND
  Recent preclinical work strongly suggests that vagus nerve stimulation efficiently modulates nociception and pain processing in humans. Most recently, a medical device has offered a transcutaneous electrical stimulation of the auricular branch of the vagus nerve (t-VNS) without any surgery.
  
  
  OBJECTIVE
  Our study investigates whether t-VNS may have the potential to alter pain processing using a controlled design.
  
  
  METHODS
  Different submodalities of the somatosensory system were assessed with quantitative sensory testing (QST) including a tonic heat pain paradigm in 48 healthy volunteers. Each subject participated in two experimental sessions with active t-VNS (stimulation) or sham t-VNS (no stimulation) on different days in a randomized order (crossed-over). One session consisted of two QST measurements on the ipsi- and contralateral hand, each before and during 1 h of a continuous t-VNS on the left ear using rectangular pulses (250 μS, 25 Hz).
  
  
  RESULTS
  We found an increase of mechanical and pressure pain threshold and a reduction of mechanical pain sensitivity. Moreover, active t-VNS significantly reduced pain ratings during sustained application of painful heat for 5 min compared to sham condition. No relevant alterations of cardiac or breathing activity or clinical relevant side effects were observed during t-VNS.
  
  
  CONCLUSIONS
  Our findings of a reduced sensitivity of mechanically evoked pain and an inhibition of temporal summation of noxious tonic heat in healthy volunteers may pave the way for future studies on patients with chronic pain addressing the potential analgesic effects of t-VNS under clinical conditions.
authors.affiliation: Department of Psychiatry and Psychotherapy, University of Regensburg, Universitätsstraße 84, 93059 Regensburg, Germany. busch.volker@gmx.de
authors.forename: Volker
authors.initials: V
authors.lastname: Busch
authors.forename: Florian
authors.initials: F
authors.lastname: Zeman
authors.forename: Andreas
authors.initials: A
authors.lastname: Heckel
authors.forename: Felix
authors.initials: F
authors.lastname: Menne
authors.forename: Jens
authors.initials: J
authors.lastname: Ellrich
authors.forename: Peter
authors.initials: P
authors.lastname: Eichhammer
mesh_terms: D000328:Adult; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D005712:Galvanic Skin Response / Q000502:physiology; D006358:Hot Temperature; D006801:Humans; D008297:Male; D010147:Pain Measurement; D058748:Pain Perception / Q000502:physiology*; D017288:Pain Threshold / Q000502:physiology*; D010812:Physical Stimulation; D004561:Transcutaneous Electric Nerve Stimulation; D055536:Vagus Nerve Stimulation