title: Measurement of the viscoelastic properties of the vocal folds.
abstract: OBJECTIVE
  Studies of the viscoelastic properties of the vocal folds are normally performed with rheometers that use parallel plates whose interplate space is usually arbitrarily assigned a fixed value. In tissues subject to variation of thickness between samples, fixed gaps could result in different compressions, compromising the comparison among them. We performed an experimental study to determine whether different compressions can lead to different results in measurements of dynamic viscosity (DV) of vocal fold samples.
  
  
  METHODS
  We measured the DV of vocal fold samples of 10 larynges of cadavers under 3 different compression levels, corresponding to 0.2, 0.5, and 10 N on an 8-mm-diameter parallel-plate rheometer.
  
  
  RESULTS
  The DV directly varied with compression. We observed statistically significant differences between the results of 0.2 and 10 N (p = 0.0396) and 0.5 and 10 N (p = 0.0442).
  
  
  CONCLUSIONS
  The study demonstrated that the level of compression influences the DV measure and suggests that a defined compression level should be used in rheometric studies of biological tissues.
authors: Disciplina de Otorrinolaringologia da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.
authors: Christian
authors: C
authors: Wiikmann
authors: Marcelo Alves
authors: MA
authors: da Silva
authors: Elizabeth Pinheiro Gomes
authors: EP
authors: Arêas
authors: Domingos Hiroshi
authors: DH
authors: Tsuji
authors: Luiz Ubirajara
authors: LU
authors: Sennes
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D019245:Compressive Strength / Q000502:physiology; D004548:Elasticity; D005260:Female; D006801:Humans; D007820:Laryngeal Mucosa / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D012212:Rheology; D046509:Tissue Culture Techniques; D014783:Viscosity; D014827:Vocal Cords / Q000503:physiopathology*