title: Fundamental Frequency of Crying in Two-month-old Boys and Girls: Do Sex Hormones During Mini-puberty Mediate Differences?
abstract: OBJECTIVE
  To evaluate whether the puberty-like sex hormone surge during the first months of life (mini-puberty) affects fundamental frequency (fo) in infant crying as one would derive from hormone influences on voice in adults.
  
  
  METHODS
  Populational prospective study.
  
  
  METHODS
  Twenty healthy normal-hearing infants (nine boys) were recruited for participation.
  
  
  METHODS
  Spontaneously uttered cries were collected from each infant at 8 weeks of age. The cries were acoustically analyzed for mean fo and fo range. The fo properties were correlated to the average serum levels of bioavailable estradiol (E2) (mean E2/sex hormone-binding globulin [SHBG]) and testosterone (T) (mean T/SHBG) across the second month of life.
  
  
  RESULTS
  Whereas no significant hormone effect was found for mean fo, a significant negative correlation (r = -0.55) was found between fo range and mean E2/SHBG. No indication for a T influence on fo features was found at this age. Although girls showed a slightly higher mean E2 concentration than boys did, the observed differences in cry fo range were judged to be reflective of an infant's serum concentration of E2 rather than a sex-based difference.
  
  
  CONCLUSIONS
  In the absence of laryngeal size differences between female and male infants, the result was interpreted as indicative of an E2 influence on viscoelastic properties of the vocal folds. In our opinion, the investigation of young infants' vocalizations during the early postnatal surge of sex steroids (mini-puberty) may advance our understanding of the mechanisms mediating average sex differences in vocal development and early communication.
authors.affiliation: Center for Pre-Speech Development and Developmental Disorders, Department of Orthodontics, University of Würzburg, Würzburg, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Borysiak
authors.affiliation: German Center for Growth, Development and Health Encouragement during Childhood and Youth, Children's Hospital Berlin-Lindenhof, Germany; Institute for Experimental Paediatric Endocrinology, Charité - University Medicine, Berlin, Germany.
authors.forename: Volker
authors.initials: V
authors.lastname: Hesse
authors.affiliation: Center for Pre-Speech Development and Developmental Disorders, Department of Orthodontics, University of Würzburg, Würzburg, Germany; IT Center, University of Würzburg, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Wermke
authors.affiliation: Department of Mathematics (Statistics), University of Würzburg, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Hain
authors.affiliation: School of Health Sciences, University of Canterbury, Christchurch, New Zealand.
authors.forename: Michael
authors.initials: M
authors.lastname: Robb
authors.affiliation: Center for Pre-Speech Development and Developmental Disorders, Department of Orthodontics, University of Würzburg, Würzburg, Germany. Electronic address: wermke_k@ukw.de.
authors.forename: Kathleen
authors.initials: K
authors.lastname: Wermke
mesh_terms: D000162:Acoustics; D000367:Age Factors; D015415:Biomarkers / Q000097:blood; D001696:Biomechanical Phenomena; D002657:Child Development; D003448:Crying; D004548:Elasticity; D004958:Estradiol / Q000097:blood*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D011446:Prospective Studies; D012737:Sex Factors; D012738:Sex Hormone-Binding Globulin / Q000032:analysis; D013018:Sound Spectrography; D013739:Testosterone / Q000097:blood*; D014783:Viscosity; D014827:Vocal Cords / Q000254:growth & development
chemical_list: D015415:Biomarkers; D012738:Sex Hormone-Binding Globulin; D013739:Testosterone; D004958:Estradiol
keywords: cry; fundamental frequency; infant; sex differences; sex hormones