title: Videokymography in voice disorders: what to look for?
abstract: OBJECTIVE
  Kymographic imaging through videokymography has been recognized as a convenient, novel way to display laryngeal behavior, yet little systematic research has been done to map the relevant features displayed in such images. Here we have aimed at specification of these features to enable systematic visual characterization and categorization of vocal fold vibratory patterns in voice disorders.
  
  
  METHODS
  A cross-sectional, descriptive design was used. We selected 45 subjects and extracted 100 videokymographic images from the archive of more than 7,000 videokymographic examinations of subjects with a wide range of voice disorders. The images showed a large variety of vocal fold vibratory behaviors during sustained phonations. We visually identified the prominent features that distinguished the vibration patterns across the images.
  
  
  RESULTS
  We divided the findings into 10 feature categories. They included refined traditional features (eg, mucosal waves), as well as additional features that are obscured in strobolaryngoscopy (eg, different types of irregularities, left-right frequency differences, shapes of lateral and medial peaks, cycle aberrations).
  
  
  CONCLUSIONS
  The variations in the identified features reveal different behavioral origins of voice disorders. The findings open new possibilities for objective documentation and for monitoring vocal fold behavior in clinical practice through kymographic imaging.
authors.affiliation: Groningen Voice Research Laboratory, Dept of Biomedical Engineering, University Medical Center Groningen, University of Groningen, Antonius Deusinglaan 1, NL 9713 AV Groningen, the Netherlands.
authors.forename: Jan G
authors.initials: JG
authors.lastname: Svec
authors.forename: Frantisek
authors.initials: F
authors.lastname: Sram
authors.forename: Harm K
authors.initials: HK
authors.lastname: Schutte
mesh_terms: D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007734:Kymography / Q000379:methods*; D007828:Laryngoscopy; D008297:Male; D009092:Mucous Membrane / Q000503:physiopathology; D012189:Retrospective Studies; D014732:Vibration; D014741:Video Recording / Q000379:methods*; D014827:Vocal Cords / Q000503:physiopathology; D014832:Voice Disorders / Q000175:diagnosis*