title: [Voice analysis before and after vocal tiredness].
abstract: OBJECTIVE
  A school teacher's occupation is one of the most vocal demanding professions. Vocal tiredness affects acoustic characteristics of voice, leads to the change in acoustic quality during vocal production. The aim of this study was to examine the influence of vocal tiredness on voice acoustic characteristics of school teachers.
  
  
  METHODS
  The study included 36 school teachers (16 male and 20 female) of 27-58 years of age. Vocal tiredness was evaluated by analyzing acoustic parameters of voice, using computerized laboratory "Kay Elemetrics". The voices were recorded before the first class on the beginning of a working week and after the last class at the end of a working week. Signal, noise and tremor parameters were processed. In their analysis the methods of descriptive statistics, as well as the analytical statistics (Student's t-test for paired samples, chi2 test, Mann Whitney U-test and Pearson's correlation coefficient) were applied.
  
  
  RESULTS
  The obtained results showed statistically significant differences in average values of parameters as a consequence of the vocal tiredness (p < 0.01), while gender, age and being smoker or not, did not have a significant effect on voice acoustic characteristics in this group of examinees (p > 0.05).
  
  
  CONCLUSIONS
  The results of the study suggest a casual relationship between vocal tiredness and voice quality in vocal professionals.
authors.affiliation: Klinicko-bolnicki centar Zvezdara, Klinika za otorinolaringologiju, Beograd, Srbija.
authors.forename: Mirjana
authors.initials: M
authors.lastname: Petrović-Lazić
authors.forename: Snezana
authors.initials: S
authors.lastname: Babac
authors.forename: Milica
authors.initials: M
authors.lastname: Tatović
authors.forename: Zoran
authors.initials: Z
authors.lastname: Ivanković
mesh_terms: D000328:Adult; D005178:Faculty; D005221:Fatigue / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009790:Occupations; D013061:Speech Acoustics; D014833:Voice Quality