title: Vocal Fold Adjustment Caused by Phonation Into a Tube: A Double-Case Study Using Computed Tomography.
abstract: OBJECTIVE
  Phonation into a tube is a widely used method for vocal training and therapy. Previous studies and practical experience show that the phonation becomes easier and louder after such an exercise. The purpose of this study was to find out whether there are systematic changes in the vocal fold adjustment after the exercise.
  
  
  METHODS
  Two volunteer subjects (1 male and 1 female) without voice disorders were examined with computed tomography (CT). Both produced a sustained vowel [a:] at comfortable pitch and loudness before and after the tube phonation and a vowel-like phonation into the tube. Computed tomography (CT) scans were obtained before, during, and after the exercise, twice for each condition. The gathered CT images were used for measurements of vertical vocal fold thickness, bulkiness, length, and glottal width.
  
  
  RESULTS
  No prominent trends common to both subjects were found in vocal fold adjustment during and after the phonation into the tube. Variability observed under the same conditions was usually of the same magnitude as the changes before and after the tube phonation.
  
  
  CONCLUSIONS
  Changes in vocal tract configuration observed after the resonance tube exercises in previous related studies were more prominent than the changes in vocal fold configuration observed here.
authors.affiliation: Department of Biophysics, Faculty of Science, Voice Research Lab, Palacky University, Olomouc, Czech Republic. Electronic address: vit.hampala@upol.cz.
authors.forename: Vít
authors.initials: V
authors.lastname: Hampala
authors.affiliation: Department of Communication Sciences and Disorders, University of Chile, Santiago, Chile.
authors.forename: Anne-Maria
authors.initials: AM
authors.lastname: Laukkanen
authors.affiliation: Department of Otolaryngology, Las Condes Clinic, Santiago, Chile.
authors.forename: Marco A
authors.initials: MA
authors.lastname: Guzman
authors.affiliation: Department of Dynamics and Vibrations, Institute of Thermomechanics, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
authors.forename: Jaromír
authors.initials: J
authors.lastname: Horáček
authors.affiliation: Department of Biophysics, Faculty of Science, Voice Research Lab, Palacky University, Olomouc, Czech Republic; Voice Centre Prague, Medical Healthcom, Ltd., Prague, Czech Republic.
authors.forename: Jan G
authors.initials: JG
authors.lastname: Švec
mesh_terms: D000328:Adult; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D008875:Middle Aged; D010699:Phonation; D014057:Tomography, X-Ray Computed; D014827:Vocal Cords / Q000000981:diagnostic imaging*
keywords: Computed tomography; Resonance tube; Vocal folds