New HRCT-Based Measurement of the Human Outer Ear Canal as a Basis for Acoustical Methods PurposeAs the form and size of the external auditory canal determine its transmitting function and hence the sound pressure in front of the eardrum, it is important to understand its anatomy in order to develop, optimize, and compare acoustical methods.MethodHigh-resolution computed tomography (HRCT) data were measured retrospectively for 100 patients ... Research Article
Research Article  |   June 01, 2013
New HRCT-Based Measurement of the Human Outer Ear Canal as a Basis for Acoustical Methods
 
Author Affiliations & Notes
  • Johanna Grewe
    Hannover Medical School, Hannover, Germany
  • Cornelia Thiele
    Hannover Medical School, Hannover, Germany
  • Hamidreza Mojallal
    Hannover Medical School, Hannover, Germany
  • Peter Raab
    Hannover Medical School, Hannover, Germany
  • Tobias Sankowsky-Rothe
    Jade College of Oldenburg, Oldenburg, Germany
  • Thomas Lenarz
    Hannover Medical School, Hannover, Germany
  • Matthias Blau
    Jade College of Oldenburg, Oldenburg, Germany
  • Magnus Teschner
    Hannover Medical School, Hannover, Germany
Article Information
Telepractice & Computer-Based Approaches / Research Article
Research Article   |   June 01, 2013
New HRCT-Based Measurement of the Human Outer Ear Canal as a Basis for Acoustical Methods
American Journal of Audiology, June 2013, Vol. 22, 65-73. doi:10.1044/1059-0889(2012/12-0039)
History: Received July 13, 2012 , Accepted August 23, 2012
 
American Journal of Audiology, June 2013, Vol. 22, 65-73. doi:10.1044/1059-0889(2012/12-0039)
History: Received July 13, 2012; Accepted August 23, 2012
Web of Science® Times Cited: 2

PurposeAs the form and size of the external auditory canal determine its transmitting function and hence the sound pressure in front of the eardrum, it is important to understand its anatomy in order to develop, optimize, and compare acoustical methods.

MethodHigh-resolution computed tomography (HRCT) data were measured retrospectively for 100 patients who had received a cochlear implant. In order to visualize the anatomy of the auditory canal, its length, radius, and the angle at which it runs were determined for the patients' right and left ears. The canal's volume was calculated, and a radius function was created.

ResultsThe determined length of the auditory canal averaged 23.6 mm for the right ear and 23.5 mm for the left ear. The calculated auditory canal volume (Vtotal) was 0.7 ml for the right ear and 0.69 ml for the left ear. The auditory canal was found to be significantly longer in men than in women, and the volume greater.

ConclusionThe values obtained can be employed to develop a method that represents the shape of the auditory canal as accurately as possible to allow the best possible outcomes for hearing aid fitting.

Acknowledgment
Part of this research was supported by Audiologie-Initiative Niedersachsen.
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