title: Collagen injection for correcting vocal fold asymmetry: high-speed imaging.
abstract: OBJECTIVE
  We hypothesized that high-speed digital imaging with videokymographic and laryngotopographic analysis would provide a quantitative method to evaluate the effect of collagen injection for the correction of asymmetric and irregular vocal fold vibration in unilateral vocal fold paralysis.
  
  
  METHODS
  Videokymographic and laryngotopographic analysis was performed for high-speed digital recordings of vocal fold vibration for visualizing the glottal vibratory patterns, and for quantifying the frequency of vibration of each vocal fold, respectively, including comparisons between the paralyzed and normal vocal folds before and after surgery. This included prospective observations of 11 subjects with unilateral vocal fold paralysis (4 male, 7 female; mean +/- SD age, 67.1 +/- 12.0 years) using high-speed digital image analysis before and after collagen injection.
  
  
  RESULTS
  Analysis of the laryngotopographs revealed 2 distinct frequencies of vibration for the paralyzed and contralateral vocal folds for 8 of the 11 subjects before surgery. After collagen injection, the vibration frequencies became identical, despite asymmetric vibration amplitudes. Asymmetric vibration amplitudes were also observed in the other 3 subjects before surgery, but the amplitudes became symmetric after collagen injection, despite a persistent phase shift.
  
  
  CONCLUSIONS
  Asymmetric vibration in vocal fold paralysis was exemplified by differences in vibration frequency and amplitude between the vocal folds. The present study showed that after collagen injection, these aspects of vibratory patterns improved toward symmetry. This surgical procedure could improve the functional symmetry of the larynx for phonation.
authors.affiliation: Dept of Otolaryngology-Head and Neck Surgery, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-9035, USA.
authors.forename: Miwako
authors.initials: M
authors.lastname: Kimura
authors.forename: Takaharu
authors.initials: T
authors.lastname: Nito
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Imagawa
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Sakakibara
authors.forename: Roger W
authors.initials: RW
authors.lastname: Chan
authors.forename: Niro
authors.initials: N
authors.lastname: Tayama
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003094:Collagen / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D007734:Kymography / Q000379:methods; D008297:Male; D008875:Middle Aged; D014732:Vibration; D014826:Vocal Cord Paralysis / Q000188:drug therapy* / Q000503:physiopathology; D014827:Vocal Cords / Q000503:physiopathology; D014833:Voice Quality
chemical_list: D003094:Collagen