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Updated: Mar 16, 2026

Author Spotlight: A Stable Phantom Material for Optical and Acoustic Imaging
Published on: June 16, 2023
Acoustic Immittance, Absorbance, and Reflectance in the Human Ear Canal
John J Rosowski1, Laura Ann Wilber2
1The Eliason Professor of Otology and Laryngology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts.
Abstract:
Ear canal measurements of acoustic immittance (a term that groups impedance and its inverse, admittance) and the related quantities of acoustic reflectance and power absorbance have been used to assess auditory function and aid in the differential diagnosis of conductive hearing loss for over 50 years. The change in such quantities after stimulation of the acoustic reflex also has been used in diagnosis. In this article, we define these quantities, describe how they are commonly measured, and discuss appropriate calibration procedures and standards necessary for accurate immittance/reflectance measurements.
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