title: A Preliminary Quantitative Comparison of Vibratory Amplitude Using Rigid and Flexible Stroboscopic Assessment.
abstract: OBJECTIVE
  The purpose of this study was to establish preliminary, quantitative data on amplitude of vibration during stroboscopic assessment in healthy speakers with normal voice characteristics. Amplitude of vocal fold vibration is a core physiological parameter used in diagnosing voice disorders, yet quantitative data are lacking to guide the determination of what constitutes normal vibratory amplitude.
  
  
  METHODS
  Eleven participants were assessed during sustained vowel production using rigid and flexible endoscopy with stroboscopy. Still images were extracted from digital recordings of a sustained /i/ produced at a comfortable pitch and loudness, with F0 controlled so that levels were within ±15% of each participant's comfortable mean level as determined from connected speech. Glottal width (GW), true vocal fold (TVF) length, and TVF width were measured from still frames representing the maximum open phase of the vibratory cycle. To control for anatomic and magnification differences across participants, GW was normalized to TVF length. GW as a ratio of TVF width was also computed for comparison with prior studies.
  
  
  RESULTS
  Mean values and standard deviations were computed for the normalized measures. Paired t tests showed no significant differences between rigid and flexible endoscopy methods. Interrater and intrarater reliability values for raw measurements were found to be high (0.89-0.99).
  
  
  CONCLUSIONS
  These preliminary quantitative data may be helpful in determining normality or abnormality of vocal fold vibration. Results indicate that quantified amplitude of vibration is similar between endoscopic methods, a clinically relevant finding for individuals performing and interpreting stroboscopic assessments.
authors.affiliation: Department of Communication Sciences and Disorders, Syracuse University, Syracuse, New York. Electronic address: chosbach@syr.edu.
authors.forename: Carly J
authors.initials: CJ
authors.lastname: Hosbach-Cannon
authors.affiliation: Department of Communication Sciences and Disorders, Syracuse University, Syracuse, New York.
authors.forename: Soren Y
authors.initials: SY
authors.lastname: Lowell
authors.affiliation: Department of Otolaryngology and Communication Sciences, Upstate Medical University, Syracuse, New York.
authors.forename: Richard T
authors.initials: RT
authors.lastname: Kelley
authors.affiliation: Department of Communication Sciences and Disorders, Syracuse University, Syracuse, New York.
authors.forename: Raymond H
authors.initials: RH
authors.lastname: Colton
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D004867:Equipment Design; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D020704:Laryngoscopes; D007828:Laryngoscopy / Q000295:instrumentation*; D008297:Male; D015588:Observer Variation; D010699:Phonation; D018583:Pliability; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D049489:Stroboscopy / Q000295:instrumentation*; D013997:Time Factors; D014732:Vibration; D014827:Vocal Cords / Q000033:anatomy & histology / Q000502:physiology*; D014833:Voice Quality; D055815:Young Adult
keywords: Amplitude; Flexible stroboscopy; Rigid stroboscopy; Stroboscopy; Vibratory amplitude