title: The Effect of Surface Hydration on Teachers' Voice Quality: An Intervention Study.
abstract: OBJECTIVE
  This study aimed to investigate the effects of surface hydration on teachers' voice quality.
  
  
  METHODS
  This is an examiner-blinded, pretest and posttest intervention study with a single group of subjects.
  
  
  METHODS
  Subjects were 27 teachers from a public-sector state school in Salvador, Bahia, Brazil. Pre- and post-intervention voice recordings were obtained. Voice samples collected underwent computerized acoustic analysis (VoxMetria) and perceptual analysis via the Consensus Auditory-Perceptual Evaluation of Voice. Intervention was conducted daily before teaching for a 4-week period, consisting of 5 minutes of nebulization with saline solution (NaCl 0.9%), after 10 minutes of dehydration breathing through the mouth.
  
  
  RESULTS
  A reduction in the overall level of voice alteration was observed in the Consensus Auditory-Perceptual Evaluation of Voice, but with no statistical significance. The following were observed: an increase in the mean fundamental frequency of the vowel /a:/ (P = 0.036); a statistically significant reduction in the minimum intensity of connected speech (P = 0.028), in the median intensity of connected speech (P = 0.014), and in the maximum intensity of connected speech (P = 0.007). There was also a statistically significant reduction in the minimum (P = 0.001) and mean intensities of spontaneous speech (P = 0.011).
  
  
  CONCLUSIONS
  Surface hydration with saline solution led to an improvement in teachers' voice quality.
authors.affiliation: Master Program of Health, Environment and Work, Federal University of Bahia (PPGSAT-UFBA), Salvador, Brazil; Undergraduate Program of Speech, Language and Hearing Sciences, União Metropolitana para Educação e Cultura University (UNIME), Lauro de Freitas, Brazil. Electronic address: emile.fono@gmail.com.
authors.forename: Émile Rocha
authors.initials: ÉR
authors.lastname: Santana
authors.affiliation: Master Program of Health, Environment and Work, Federal University of Bahia (PPGSAT-UFBA), Salvador, Brazil; Department of Speech, Language and Hearing Sciences, Federal University of Bahia (UFBA), Salvador, Brazil.
authors.forename: Maria Lúcia Vaz
authors.initials: MLV
authors.lastname: Masson
authors.affiliation: Master Program of Health, Environment and Work, Federal University of Bahia (PPGSAT-UFBA), Salvador, Brazil; Department of Health, State University of Feira de Santana (UEFS), Feira de Santana, Brazil.
authors.forename: Tânia Maria
authors.initials: TM
authors.lastname: Araújo
mesh_terms: D000162:Acoustics; D000280:Administration, Inhalation; D000328:Adult; D001307:Auditory Perception; D001938:Brazil; D003681:Dehydration / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D005260:Female; D006801:Humans; D007600:Judgment; D008297:Male; D009330:Nebulizers and Vaporizers; D016272:Occupational Health; D020127:Recovery of Function; D000070777:School Teachers; D012815:Signal Processing, Computer-Assisted; D012965:Sodium Chloride / Q000008:administration & dosage*; D013068:Speech Production Measurement; D013499:Surface Properties; D013997:Time Factors; D016896:Treatment Outcome; D014827:Vocal Cords / Q000503:physiopathology*; D014832:Voice Disorders / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D014833:Voice Quality
chemical_list: D012965:Sodium Chloride
keywords: Hydration of the vocal fold; Occupational health; Teachers; Teaching; Voice disorders