title: Endoscopic measurement of vocal fold movement during adduction and abduction.
abstract: OBJECTIVE
  Whereas vibration of the vocal folds has been analyzed and modeled in detail, less attention has been paid to quantifying the slower motions of abduction and adduction. Because these gestures reflect neuromuscular function, cartilage geometry, and joint mobility, objective measurement might improve assessment and treatment of patients with neuromuscular or structural disease.
  
  
  METHODS
  Prospective, observational.
  
  
  METHODS
  Twenty-one normal adult volunteers performed a repeated "ee-sniff" task at three rates during flexible endoscopy. Distortion in the images was corrected and frame-by-frame analysis of the angle between the true vocal folds (glottic angle) yielded measures of maximum abduction angle (MAA) and mean angular velocities of abduction (MVAB) and adduction (MVAD).
  
  
  RESULTS
  Reliability tests indicated interjudge variability of 3.8 degrees (deg). The mean MAA was 51 deg and ranged from 31 to 77 deg across subjects. The mean MVADs were 229, 309, and 475 deg/s for slow, medium, and fast rates, respectively, and the mean MVABs were 330, 388, and 441 deg/s for slow, medium, and fast rates, respectively. Statistical analysis showed greater influence of gesture rate on adduction than on abduction.
  
  
  CONCLUSIONS
  The glottic angle can be reliably measured from flexible endoscopic images and angular velocities of vocal fold abduction and adduction can be determined from analysis of sequential video frames. Accuracy is significantly enhanced by correction of distortion in the images. This approach holds promise for objective characterization of vocal fold function in patients with a variety of disorders.
authors.affiliation: Department of Otology and Laryngology, Harvard Medical School, Division of Otolaryngology, Brigham and Women's Hospital, Boston, MA 02115, USA.
authors.forename: Seth H
authors.initials: SH
authors.lastname: Dailey
authors.forename: James B
authors.initials: JB
authors.lastname: Kobler
authors.forename: Robert E
authors.initials: RE
authors.lastname: Hillman
authors.forename: Kittisard
authors.initials: K
authors.lastname: Tangrom
authors.forename: Ekawudh
authors.initials: E
authors.lastname: Thananart
authors.forename: Marcelo
authors.initials: M
authors.lastname: Mauri
authors.forename: Steven M
authors.initials: SM
authors.lastname: Zeitels
mesh_terms: D000328:Adult; D004724:Endoscopy; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D001239:Inhalation; D009068:Movement; D010699:Phonation / Q000502:physiology; D012016:Reference Values; D014827:Vocal Cords / Q000502:physiology*