title: The influence of water resistance therapy on vocal fold vibration: a high-speed digital imaging study.
abstract: OBJECTIVE
  This study investigated the influence of tube phonation into water on vocal fold vibration.
  
  
  METHODS
  Eight participants were analyzed via high-speed digital imaging while phonating into a silicon tube with the free end submerged into water. Two test sequences were studied: (1) phonation pre, during, and post tube submerged 5 cm into water; and (2) phonation into tube submerged 5 cm, 10 cm, and 18 cm into water. Several glottal area parameters were calculated using phonovibrograms.
  
  
  RESULTS
  The results showed individual differences. However, certain trends were possible to identify based on similar results found for the majority of participants. Amplitude-to-length ratio, harmonic-to-noise ratio, and spectral flatness (derived from glottal area) decreased for all tube immersion depths, while glottal closing quotient increased for 10 cm immersion and contact quotient for 18 cm immersion. Closed quotient decreased during phonation into the tube at 5 cm depth, and jitter decreased during and after it.
  
  
  CONCLUSIONS
  Results suggest that the depth of tube submersion appears to have an effect on phonation. Shallow immersion seems to promote smoother and more stable phonation, while deeper immersion may involve increased respiratory and glottal effort to compensate for the increased supraglottal resistance. This disparity, which is dependent upon the degree of flow resistance, should be considered when choosing treatment exercises for patients with various diagnoses, namely hyperfunctional or hypofunctional dysphonia.
authors.affiliation: a Department of Communication Sciences and Disorders , University of Chile , Santiago , Chile.|b Department of Otolaryngology , Las Condes Clinic , Santiago , Chile.
authors.forename: Marco
authors.initials: M
authors.lastname: Guzman
authors.affiliation: c Speech and Voice Research Laboratory, School of Education , University of Tampere , Tampere , Finland.
authors.forename: Anne-Maria
authors.initials: AM
authors.lastname: Laukkanen
authors.affiliation: d Institute of Musicians' Medicine, Freiburg University Medical Center , Freiburg , Germany.
authors.forename: Louisa
authors.initials: L
authors.lastname: Traser
authors.affiliation: e Department of Otorhinolaryngology and Phoniatrics-Head and Neck Surgery , Helsinki University Central Hospital, University of Helsinki , Helsinki , Finland.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Geneid
authors.affiliation: d Institute of Musicians' Medicine, Freiburg University Medical Center , Freiburg , Germany.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Richter
authors.affiliation: f Department of Otolaryngology , University of Chile , Santiago , Chile.
authors.forename: Daniel
authors.initials: D
authors.lastname: Muñoz
authors.affiliation: d Institute of Musicians' Medicine, Freiburg University Medical Center , Freiburg , Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Echternach
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007828:Laryngoscopy; D008297:Male; D008875:Middle Aged; D010699:Phonation; D010781:Photography; D011312:Pressure; D013997:Time Factors; D014732:Vibration; D014827:Vocal Cords / Q000000981:diagnostic imaging* / Q000502:physiology*; D014833:Voice Quality; D014834:Voice Training; D014867:Water; D055815:Young Adult
chemical_list: D014867:Water
keywords: High-speed digital imaging; phonovibrograms; semi-occlusion; tube phonation; voice therapy