title: Quantitative assessment of videolaryngostroboscopic images in patients with glottic pathologies.
abstract: BACKGROUND
  Digital imaging techniques enable exploration of novel visualization modalities of the vocal folds during phonation and definition of parameters, facilitating more precise diagnosis of voice disorders.
  
  
  OBJECTIVE
  Application of computer vision algorithms for analysis of videolaryngostroboscopic (VLS) images aimed at qualitative and quantitative description of phonatory vibrations.
  
  
  METHODS
  VLS examinations were conducted for 45 females, including 15 subjects with vocal nodules, 15 subjects with glottal incompetence, and 15 normophonic females. The recorded VLS images were preprocessed, the glottis area was segmented out, and the glottal cycles were identified. The glottovibrograms were built, and then the glottal area waveforms (GAW) were quantitatively described by computing the following parameters: open quotient (OQ), closing quotient (CQ), speed quotient (SQ), minimal relative glottal area (MRGA), and a new parameter termed closure difference index (CDI).
  
  
  RESULTS
  Profiles of the glottal widths assessed along the glottal length differentiated the study groups (P < 0.001). Moreover, it was shown that the OQ, CQ, CDI, and MRGA indices can be considered as viable parameters for quantifying kinematics of the vocal folds for normophonic subjects and patients with diagnosed vocal nodules and glottal incompetence (P < 0.001).
  
  
  CONCLUSIONS
  Computer image processing and analysis methods applied to videolaryngostroboscopic images allow for their quantitative assessment. Computation of the size-related and time-related parameters characterizing glottic pathologies is of interest for evidence-based voice diagnostics. Results of the performed ROC curve analysis suggest that the evaluated parameters can distinguish patients with voice disorders from normophonic subjects.
authors.affiliation: a Department of Audiology and Phoniatrics , the Nofer Institute of Occupational Medicine , Lodz , Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Niebudek-Bogusz
authors.affiliation: b Institute of Electronics, Technical University of Lodz , Poland.
authors.forename: Bartosz
authors.initials: B
authors.lastname: Kopczynski
authors.affiliation: b Institute of Electronics, Technical University of Lodz , Poland.
authors.forename: Pawel
authors.initials: P
authors.lastname: Strumillo
authors.affiliation: a Department of Audiology and Phoniatrics , the Nofer Institute of Occupational Medicine , Lodz , Poland.
authors.forename: Joanna
authors.initials: J
authors.lastname: Morawska
authors.affiliation: c Department of Economic and Social Statistics , University of Lodz , Poland.
authors.forename: Justyna
authors.initials: J
authors.lastname: Wiktorowicz
authors.affiliation: a Department of Audiology and Phoniatrics , the Nofer Institute of Occupational Medicine , Lodz , Poland.
authors.forename: Mariola
authors.initials: M
authors.lastname: Sliwinska-Kowalska
mesh_terms: D000328:Adult; D000465:Algorithms; D019540:Area Under Curve; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007818:Laryngeal Diseases / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology; D007828:Laryngoscopy / Q000379:methods*; D008875:Middle Aged; D010699:Phonation; D011237:Predictive Value of Tests; D012372:ROC Curve; D049489:Stroboscopy; D013997:Time Factors; D014732:Vibration; D014741:Video Recording; D014827:Vocal Cords / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology; D014832:Voice Disorders / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology; D014833:Voice Quality; D055815:Young Adult
keywords: Glottal pathologies; glottovibrograms; quantitative analysis; software for processing images of larynx; videolaryngostroboscopy; voice disorders