title: Measurement of glottal cycle characteristics between children and adults: physiological variations.
abstract: OBJECTIVE
  The aim of this study was to quantify phases of the vibratory cycle using measurements of glottal cycle quotients and glottal cycle derivatives, in typically developing prepubertal children and young adults with the use of high-speed digital imaging (HSDI).
  
  
  METHODS
  Vocal fold vibrations were recorded from 27 children (age range 5-9 years) and 35 adults (age range 21-45 years), with HSDI at 4000 frames per second for sustained phonation. Glottal area waveform measures of Open Quotient, Closing Quotient, Speed Index (SI), Rate Quotient, and Asymmetry Quotient (AsyQ) were computed. Glottal cycle derivatives of Amplitude Quotient (AQ) and Maximum Area Declination Rate (MADR) were also computed. Group differences (adult females, adult males, and children) were statistically investigated for mean and standard deviation values of the glottal cycle quotients and glottal cycle derivatives.
  
  
  RESULTS
  Children exhibited higher values of SI and AsyQ and lower values of MADR compared with adult males. Children exhibited the highest mean value and lowest variability in AQ compared with adult males and females. Adult males showed lower values of SI, AsyQ, AQ, and higher values of MADR compared with adult females.
  
  
  CONCLUSIONS
  Glottal cycle vibratory motion in children is functionally different compared with adult males and females, suggesting the need for development of children specific norms for both normal and disordered voice qualities.
authors.affiliation: Department Speech and Hearing Sciences, College of Arts and Sciences, Indiana University, Bloomington, Indiana. Electronic address: patelrir@indiana.edu.
authors.forename: Rita R
authors.initials: RR
authors.lastname: Patel
authors.affiliation: Department of Phoniatrics and Pediatric Audiology, University Hospital Erlangen, Medical School, Erlangen, Germany.
authors.forename: Denis
authors.initials: D
authors.lastname: Dubrovskiy
authors.affiliation: Department of Phoniatrics and Pediatric Audiology, University Hospital Erlangen, Medical School, Erlangen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Döllinger
mesh_terms: D000328:Adult; D000367:Age Factors; D001696:Biomechanical Phenomena; D002648:Child; D002675:Child, Preschool; D005260:Female; D005931:Glottis / Q000254:growth & development* / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D010699:Phonation / Q000502:physiology*; D012737:Sex Factors; D013060:Speech / Q000502:physiology; D014827:Vocal Cords / Q000254:growth & development / Q000502:physiology; D014831:Voice / Q000502:physiology*; D055815:Young Adult
keywords: Glottal cycle; High-speed laryngeal imaging; Objective voice evaluation; Pediatric voice; Vocal fold vibrations