title: Impact of Vagal Nerve Stimulation on Objective Vocal Quality, a Pilot Study.
abstract: OBJECTIVE
  The purpose of this study was to determine the impact of vagal nerve stimulation (VNS) on the vocal quality using the dysphonia severity index (DSI). It was hypothesized that the objective vocal quality and other vocal characteristics are disordered in comparison with an age- and gender-matched control group. In addition, the acoustic vocal parameters were compared during three conditions: at rest, during normal stimulation, and raised stimulation. A significant relation between the amount of stimulation and the presence of disturbed acoustic parameters was hypothesized.
  
  
  METHODS
  Subjective (auditory-perceptual evaluation and voice handicap index) and objective (aerodynamic, vocal range, acoustic measurements and determination of the DSI) measurements were used to determine the vocal quality in 13 subjects with VNS in three different conditions (at rest and during normal and raised stimulation) and the age- and gender-matched control group.
  
  
  RESULTS
  The subjects with VNS had a disordered perceptual vocal quality mainly characterized by the presence of a moderate roughness and slight breathiness, and the objective vocal quality by means of the DSI value is -2.4. During stimulation and especially during raised stimulation, the fundamental frequency is significantly increased. However, the subjects experienced no psychosocial handicapping effect of the vocal quality on the quality of life.
  
  
  CONCLUSIONS
  Subjects with VNS have typical vocal characteristics. Ear, nose, and throat specialists and voice therapist must be aware of the presence of this vocal pattern at rest and during normal and raised stimulation. Especially, professional voice users and elite vocal performers must be informed before implantation.
authors: Department of Speech, Language, and Hearing Sciences, Ghent University, Gent, Belgium. Electronic address: kristiane.vanlierde@ugent.be.
authors: Kristiane
authors: K
authors: Van Lierde
authors: Department of Ear, Nose, and Throat and Head and Neck Surgery, Ghent University, Gent, Belgium.
authors: Marina
authors: M
authors: Kryshtopava
authors: Reference Center for Refractory Epilepsy, Department of Neurology, Ghent University, Gent, Belgium.
authors: Stefanie
authors: S
authors: Gadeyne
authors: Department of Speech, Language, and Hearing Sciences, Ghent University, Gent, Belgium.
authors: Anke
authors: A
authors: Luyten
authors: Department of Speech, Language, and Hearing Sciences, Ghent University, Gent, Belgium.
authors: Evelien
authors: E
authors: D'haeseleer
authors: Department of Speech, Language, and Hearing Sciences, Ghent University, Gent, Belgium.
authors: Laura
authors: L
authors: Bruneel
authors: Department of Biostatistics, Ghent University, Gent, Belgium.
authors: George
authors: G
authors: Van Maele
authors: Department of Speech, Language, and Hearing Sciences, Ghent University, Gent, Belgium.
authors: Beatrijs
authors: B
authors: Boehme
authors: Department of Speech, Language, and Hearing Sciences, Ghent University, Gent, Belgium.
authors: Nina
authors: N
authors: Piens
authors: Reference Center for Refractory Epilepsy, Department of Neurology, Ghent University, Gent, Belgium.
authors: Kristl
authors: K
authors: Vonck
mesh_terms: D000328:Adult; D004827:Epilepsy / Q000628:therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D055536:Vagus Nerve Stimulation / Q000009:adverse effects*; D014832:Voice Disorders / Q000209:etiology*; D014833:Voice Quality; D055815:Young Adult
keywords: Dysphonia severity index; Vagal nerve stimulation; Vocal quality; Voice handicap index