title: Quantification of change in vocal fold tissue stiffness relative to depth of artificial damage.
abstract: OBJECTIVE
  To quantify changes in the biomechanical properties of human excised vocal folds with defined artificial damage.
  
  
  METHODS
  The linear skin rheometer (LSR) was used to obtain a series of rheological measurements of shear modulus from the surface of 30 human cadaver vocal folds. The tissue samples were initially measured in a native condition and then following varying intensities of thermal damage. Histological examination of each vocal fold was used to determine the depth of artificial alteration. The measured changes in stiffness were correlated with the depth of cell damage.
  
  
  RESULTS
  For vocal folds in a pre-damage state the shear modulus values ranged from 537 Pa to 1,651 Pa (female) and from 583 Pa to 1,193 Pa (male). With increasing depth of damage from the intermediate layer of the lamina propria (LP), tissue stiffness increased consistently (compared with native values) following application of thermal damage to the vocal folds. The measurement showed an increase of tissue stiffness when the depth of tissue damage was extending from the intermediate LP layer downwards.
  
  
  CONCLUSIONS
  Changes in the elastic characteristics of human vocal fold tissue following damage at defined depths were demonstrated in an in vitro experiment. In future, reproducible in vivo measurements of elastic vocal fold tissue alterations may enable phonosurgeons to infer the extent of subepithelial damage from changes in surface elasticity.
authors: a Department of Voice, Speech and Hearing Disorders , University Medical Center Hamburg-Eppendorf , Germany.
authors: Anna-Katharina
authors: AK
authors: Rohlfs
authors: a Department of Voice, Speech and Hearing Disorders , University Medical Center Hamburg-Eppendorf , Germany.
authors: Sebastian
authors: S
authors: Schmolke
authors: b Department of Pathology , University Medical Center Hamburg-Eppendorf , Germany.
authors: Till
authors: T
authors: Clauditz
authors: a Department of Voice, Speech and Hearing Disorders , University Medical Center Hamburg-Eppendorf , Germany.
authors: Markus
authors: M
authors: Hess
authors: a Department of Voice, Speech and Hearing Disorders , University Medical Center Hamburg-Eppendorf , Germany.
authors: Frank
authors: F
authors: Müller
authors: c Institute for Forensic Medicine, University Medical Center Hamburg-Eppendorf , Germany.
authors: Klaus
authors: K
authors: Püschel
authors: d Department of Radiology , University of Erlangen-Nuremberg , Erlangen , Germany.
authors: Frank W
authors: FW
authors: Roemer
authors: e Department of Anatomy and Experimental Morphology , University Medical Center Hamburg-Eppendorf , Germany.
authors: Udo
authors: U
authors: Schumacher
authors: f Centre for Computational Intelligence-Bioinformatics Group , De Montfort University , Leicester , United Kingdom.
authors: Eric
authors: E
authors: Goodyer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D002102:Cadaver; D055119:Elastic Modulus; D005260:Female; D006358:Hot Temperature / Q000009:adverse effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D010699:Phonation; D012212:Rheology; D012737:Sex Factors; D013997:Time Factors; D014827:Vocal Cords / Q000293:injuries* / Q000473:pathology / Q000503:physiopathology*; D055815:Young Adult
keywords: Artificial damage; biomechanical properties; human vocal fold; linear skin rheometer