title: Assessment of brainstem function with auricular branch of vagus nerve stimulation in Parkinson's disease.
abstract: BACKGROUND
  The efferent dorsal motor nucleus of the vagal nuclei complex may degenerate early in the course of Parkinson's disease (PD), while efferent nucleus ambiguous, the principal source of parasympathetic vagal neurons innervating the heart, and afferent somatosensory nuclei remain intact.
  
  
  OBJECTIVE
  To obtain neurophysiological evidence related to this pattern, we tested processing of afferent sensory information transmitted via the auricular branch of the vagus nerve (ABVN) which is known to be connected to autonomic regulation of cardiac rhythm.
  
  
  METHODS
  In this cross-sectional observational study, we recorded (i) somatosensory evoked potentials (ABVN-SEP) and (ii) cutaneo-cardioautonomic response elicited by stimulation of the ABVN (modulation of heart-rate variability (HRV index; low frequency power, ln(LF), high frequency power, ln(HF); ln(LF/HF) ratio)) in 50 PD patients and 50 age and sex matched healthy controls. Additionally, auditory evoked potentials and trigeminal nerve SEP were assessed.
  
  
  RESULTS
  Neither ABVN-SEP nor any of the other functional brainstem parameters differed between patients and controls. Although HRV index was decreased in PD patients, modulation of ln(LF/HF) by ABVN-stimulation, likely indicating cardiac parasympathetic activation, did not differ between both groups.
  
  
  CONCLUSIONS
  Findings do not point to prominent dysfunction of processing afferent information from ABVN and its connected parasympathetic cardiac pathway in PD. They are consistent with the known pattern of degeneration of the vagal nuclei complex of the brainstem.
authors: Department of Neurology, University of Leipzig, Leipzig, Germany.
authors: David
authors: D
authors: Weise
authors: Department of Neurology, University of Leipzig, Leipzig, Germany.
authors: Melanie
authors: M
authors: Adamidis
authors: Department of Neurology, University of Leipzig, Leipzig, Germany; Department of Neurological, Neuropsychological, Morphological and Movement Sciences, University of Verona, Verona, Italy.
authors: Fabio
authors: F
authors: Pizzolato
authors: Department of Neurology, University of Leipzig, Leipzig, Germany.
authors: Jost-Julian
authors: JJ
authors: Rumpf
authors: Department of Neurology, University of Leipzig, Leipzig, Germany.
authors: Christopher
authors: C
authors: Fricke
authors: Department of Neurology, University of Leipzig, Leipzig, Germany.
authors: Joseph
authors: J
authors: Classen
mesh_terms: D001933:Brain Stem / Q000502:physiology*; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000503:physiopathology* / Q000628:therapy*; D011379:Prognosis; D055536:Vagus Nerve Stimulation / Q000379:methods*