title: Phonation threshold flow in elongated excised larynges.
abstract: OBJECTIVE
  This study proposes the use of a new parameter of vocal aerodynamics, phonation threshold flow (PTF). The sensitivities of the PTF and the phonation threshold pressure (PTP) were quantitatively compared to the percent of vocal fold elongation from physiologic length.
  
  
  METHODS
  Ten excised canine larynges were mounted on a bench apparatus capable of controlling vocal fold elongation. Subglottal airflow was gradually increased until the onset of phonation. Elongation of the vocal folds was varied from +0% (physiologic length) to +15%, and the PTF and PTP were measured.
  
  
  RESULTS
  The mean PTFs at physiologic vocal fold length ranged from 101 to 217 mL/s. No statistically significant relationship was found to exist between the size of the larynx and the measured PTF values (p = .404). The average percent change of PTF compared to the magnitude of elongation was found to be statistically significant (p < .001). The data indicated that the PTF was proportional to the percent of vocal fold elongation.
  
  
  CONCLUSIONS
  The PTF was positively correlated with vocal fold elongation and the PTP for small magnitudes of elongation. The results suggest that the PTF may be indicative of the biomechanical properties of the vocal folds, thus providing a possibly valuable tool in the clinical evaluation of laryngeal function.
authors.affiliation: Department of Surgery, Division of Otolaryngology-Head and Neck Surgery, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA.
authors.forename: Jack J
authors.initials: JJ
authors.lastname: Jiang
authors.forename: Michael F
authors.initials: MF
authors.lastname: Regner
authors.forename: Chao
authors.initials: C
authors.lastname: Tao
authors.forename: Steven
authors.initials: S
authors.lastname: Pauls
mesh_terms: D000392:Air Movements; D000818:Animals; D001696:Biomechanical Phenomena; D004285:Dogs; D066298:In Vitro Techniques; D007830:Larynx / Q000502:physiology*; D010699:Phonation / Q000502:physiology*; D014827:Vocal Cords / Q000502:physiology