title: Instability of voice in adolescence: pathologic condition or normal developmental variation?
abstract: OBJECTIVE
  Pediatricians often send adolescents with dysphonia to the otorhinolaryngologist's office to find the reason for their hoarseness. The aim of this study was to identify the main characteristics of adolescent voice and to determine which characteristic (variable of voice analysis) can distinguish normal variations of voice development from pathologic disorders.
  
  
  METHODS
  On the basis of history, indirect laryngoscopy, and stroboscopy, 51 adolescents (22 boys, 29 girls) from age 10 to 17 years were divided into four subgroups: candidates for singing lessons without voice problems, subjects with mutation voice disorders, subjects with functional dysphonia, and subjects with vocal cord nodules. Voice analysis by Multi-Dimensional Voice Program (Kay Elemetrics) evaluated the fundamental frequency, the variability of pitch and amplitude (loudness), and the presence of noise in the analyzed voice sample of each of the subjects. Data were analyzed with the SPSS+/PC Statistical Program.
  
  
  RESULTS
  All mean values of variables that describe variability of pitch and amplitude were abnormal in boys and in girls, with greater abnormality among boys. The variability of loudness and specifically the variability of pitch were abnormal in a majority of subjects. A significant negative correlation between age and fundamental frequency was stated in boys only and between age and variability of amplitude in girls only. Variables that express variability of pitch and amplitude correlated positively between themselves. No significant differences were found between the first subgroup (candidates for singing lessons), which represented a normal population, and the other three subgroups (subjects with mutational disorders, functional dysphonia, and vocal cord nodules). In addition, no significant differences were found between the first three subgroups (subjects without voice problems and subjects with functional voice disorders) and the fourth subgroup (subjects with vocal cord nodules: organic lesion of laryngeal mucosa).
  
  
  CONCLUSIONS
  According to this study, the main characteristic of adolescent voice is the instability of amplitude (loudness) and specifically the instability of pitch. Female voices appear more stable than male voices. No single variable of performed voice analysis can distinguish normal variation of voice development from pathologic disorders. The reason for this instability can be attributed to more gradual adaptation of the afferent and efferent nervous control to the rapid growth of the phonatory, respiratory, and resonatory organs. In the growing speech apparatus, optimal phonatory patterns can be created; therefore adolescence is an ideal period for treatment of functional voice disorders.
authors.affiliation: University Department of Otorhinolaryngology, Ljubljana, Slovenia.
authors.forename: I H
authors.initials: IH
authors.lastname: Boltezar
authors.forename: Z R
authors.initials: ZR
authors.lastname: Burger
authors.forename: M
authors.initials: M
authors.lastname: Zargi
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D016009:Chi-Square Distribution; D002648:Child; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007828:Laryngoscopy / Q000706:statistics & numerical data; D008297:Male; D012016:Reference Values; D012815:Signal Processing, Computer-Assisted; D014831:Voice; D014832:Voice Disorders / Q000175:diagnosis*