title: The Interaction of Surface Hydration and Vocal Loading on Voice Measures.
abstract: OBJECTIVE
  Vocal loading tasks provide insight regarding the mechanisms underlying healthy laryngeal function. Determining the manner in which the larynx can most efficiently be loaded is a complex task. The goal of this study was to determine if vocal loading could be achieved in 30 minutes by altering phonatory mode. Owing to the fact that surface hydration facilitates efficient vocal fold oscillation, the effects of environmental humidity on vocal loading were also examined. This study also investigated whether the detrimental effects of vocal loading could be attenuated by increasing environmental humidity.
  
  
  METHODS
  Sixteen vocally healthy adults (8 men, 8 women) completed a 30-minute vocal loading task in low and moderate humidity. The order of humidities was counterbalanced across subjects. The vocal loading task consisted of reading with elevated pitch and pressed vocal quality and low pitch and pressed and/or raspy vocal quality in the presence of 65 dB ambient, multi-talker babble noise.
  
  
  RESULTS
  Significant effects were observed for (1) cepstral peak prominence on soft sustained phonation at 10th and 80th pitches, (2) perceived phonatory effort, and (3) perceived tiredness ratings. No loading effects were observed for cepstral peak prominence on the rainbow passage, although fundamental frequency on the rainbow passage increased post loading. No main effect was observed for humidity.
  
  
  CONCLUSIONS
  Following a 30-minute vocal loading task involving altering laryngeal vibratory mode in combination with increased volume. Also, moderate environmental humidity did not significantly attenuate the negative effects of loading.
authors: Department of Speech, Language and Hearing Sciences, Purdue University, West Lafayette, Indiana.
authors: Robert Brinton
authors: RB
authors: Fujiki
authors: Department of Speech, Language and Hearing Sciences, Purdue University, West Lafayette, Indiana.
authors: Abigail
authors: A
authors: Chapleau
authors: Department of Speech, Language and Hearing Sciences, Purdue University, West Lafayette, Indiana.
authors: Anusha
authors: A
authors: Sundarrajan
authors: Department of Speech, Language and Hearing Sciences, Boston University, Boston, Massachusetts.
authors: Victoria
authors: V
authors: McKenna
authors: Department of Speech, Language and Hearing Sciences, Purdue University, West Lafayette, Indiana. Electronic address: msivasan@purdue.edu.
authors: M Preeti
authors: MP
authors: Sivasankar
mesh_terms: D000162:Acoustics; D000293:Adolescent; D000328:Adult; D001696:Biomechanical Phenomena; D001834:Body Water / Q000378:metabolism*; D004777:Environment; D005260:Female; D006801:Humans; D006813:Humidity; D007600:Judgment; D007830:Larynx / Q000378:metabolism*; D008297:Male; D009622:Noise / Q000009:adverse effects; D010699:Phonation; D010898:Pitch Perception; D012815:Signal Processing, Computer-Assisted; D013061:Speech Acoustics; D013065:Speech Intelligibility; D013067:Speech Perception; D013068:Speech Production Measurement; D013499:Surface Properties; D013997:Time Factors; D014732:Vibration; D014833:Voice Quality; D055815:Young Adult
keywords: acoustics; fatigue; soft voice; surface hydration; vocal loading