title: Reliable acoustic measurements in children between 5;0 and 9;11 years: Gender, age, height and weight effects on fundamental frequency, jitter and shimmer in phonations without and with controlled voice SPL.
abstract: BACKGROUND
  Current pediatric voice assessment guidelines include instrumental measurements of fundamental frequency (F0) and the perturbation indices jitter and shimmer. In children below 10 years, gender, age, height and weight effects on these parameters have been inconsistently characterized. Recent research in healthy children showed, that differences in habitual speaking voice intensity (voice SPL) under the usual assessment procedure significantly affect jitter and shimmer. These effects were reduced in phonations with controlled voice SPL >80dBA. Reliable measurement methods and description of physiologic influencing factors are essential to identify pathologic voices.
  
  
  OBJECTIVE
  This cross-sectional single cohort study investigates in children between 5;0 and 9;11 years how gender, age, height and weight affect voice F0, jitter and shimmer in phonations at individually "medium" voice intensity (modeling the usual clinical practice) and with controlled voice SPL >80dBA.
  
  
  METHODS
  68 vocally healthy children (39 f/29 m) aged 5;0-9;11 years provided 3 prolonged phonations of/a/at individually "medium" and controlled voice intensity at ">80dBA" (visual feedback, 10cm distance). F0 (Hz), jitter (%), shimmer (%) and voice SPL (dBA) were determined with PRAAT. Gender, age, height and weight effects without and with controlled voice SPL were assessed by descriptive statistics, Analysis of Variance and Linear Mixed Models.
  
  
  RESULTS
  F0 (Hz), jitter (%), shimmer (%) and voice SPL (dBA) were significantly different in medium voice compared to >80dBA (p<0.01). In medium phonations girls had a higher F0 than boys (girls: 276.7(50.7), boys: 261.5(33.7)), but with >80dBA this difference was only minimal (girls: 328.9(52.2), boys 327.9(51.2)). Mean jitter (0.27(0.10)) and shimmer (4.34(1.68)) were smaller and showed less spread (jitter: 0.5(0.26); shimmer: 9.47(3.47)) with >80dBA. Gender, age, height and weight had no significant effects on F0, jitter, shimmer and voice SPL in both phonation types (p-range=0.42-0.99).
  
  
  CONCLUSIONS
  Neither without nor with controlled voice SPL there were systematic gender, age, height or weight effects on voice F0, jitter and shimmer. Gender related F0 discrepancies were equalized in phonations with >80dBA. In children below 10 years gender related acoustic voice differences may be mainly linked to behavior, which should be considered in future works regarding physiologic voice development.
authors.affiliation: Department of Phoniatrics and Speech Pathology, Clinic for Otorhinolaryngology, Head and Neck Surgery, University Hospital Zurich, University of Zurich, Frauenklinikstrasse 24, 8091 Zurich, Switzerland. Electronic address: meike.brockmann-bauser@usz.ch.
authors.forename: Meike
authors.initials: M
authors.lastname: Brockmann-Bauser
authors.affiliation: Department of Phoniatrics and Speech Pathology, Clinic for Otorhinolaryngology, Head and Neck Surgery, University Hospital Zurich, University of Zurich, Frauenklinikstrasse 24, 8091 Zurich, Switzerland. Electronic address: denisbeyer@gmail.com.
authors.forename: Denis
authors.initials: D
authors.lastname: Beyer
authors.affiliation: Department of Phoniatrics and Speech Pathology, Clinic for Otorhinolaryngology, Head and Neck Surgery, University Hospital Zurich, University of Zurich, Frauenklinikstrasse 24, 8091 Zurich, Switzerland. Electronic address: Joerg.Bohlender@usz.ch.
authors.forename: Jörg Edgar
authors.initials: JE
authors.lastname: Bohlender
mesh_terms: D000367:Age Factors; D001835:Body Weight; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D010699:Phonation / Q000502:physiology*; D012737:Sex Factors; D013061:Speech Acoustics; D014833:Voice Quality / Q000502:physiology*
keywords: Children; Fundamental frequency; Jitter; Prosody; Shimmer; Voice disorders