title: The effects of alterations in the osseous external auditory canal on perceived sound quality.
abstract: OBJECTIVE
  To evaluate the perceptual effect of the altered shape of the osseous external auditory canal (OEAC) on sound quality.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  Twenty subjects with normal hearing were presented with six simulated sound conditions representing the acoustic properties of six different ear canals (three normal ears and three cavities). The six different real ear unaided responses of these ear canals were used to filter Dutch sentences, resulting in six simulated sound conditions. A seventh unfiltered reference condition was used for comparison. Sound quality was evaluated using paired comparison ratings and a visual analog scale (VAS).
  
  
  RESULTS
  Significant differences in sound quality were found between the normal and cavity conditions (all P < .001) using both the seven-point paired comparison rating and the VAS. No significant differences were found between the reference and normal conditions. Sound quality deteriorates when the OEAC is altered into a cavity.
  
  
  CONCLUSIONS
  This proof of concept study shows that the altered acoustic quality of the OEAC after radical cavity surgery may lead to a clearly perceived deterioration in sound quality. Nevertheless, some questions remain about the extent to which these changes are affected by habituation and by other changes in middle ear anatomy and functionality.
  
  
  METHODS
  4
authors.affiliation: Department of Otorhinolaryngology, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Erik
authors.initials: E
authors.lastname: van Spronsen
authors.affiliation: Department of Otorhinolaryngology, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Patrick
authors.initials: P
authors.lastname: Brienesse
authors.affiliation: Department of Otorhinolaryngology, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Fenna A
authors.initials: FA
authors.lastname: Ebbens
authors.affiliation: Department of Otorhinolaryngology, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Jerome J
authors.initials: JJ
authors.lastname: Waterval
authors.affiliation: Department of Otorhinolaryngology, Academic Medical Center, Amsterdam, the Netherlands.
authors.forename: Wouter A
authors.initials: WA
authors.lastname: Dreschler
mesh_terms: D000162:Acoustics; D000328:Adult; D004424:Ear Canal; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D011446:Prospective Studies; D013016:Sound; D055815:Young Adult
keywords: Ear canal; acoustics; sound quality