Measurements of middle ear functioning- traditional (acoustic impedance and acoustic admittance) and modern (middle ear reflectance and middle ear absorbance): a review


  • Udit Saxena MAA Institute of Speech and Hearing, Hyderabad, India
  • S. B. Rathna Kumar Ali Yavar Jung National institute of Speech and Hearing Disabilities, Divyangjan, Mumbai, India
  • Bhanu Pratap Singh Hind Institute of Medical Sciences, Sitapur, Uttar Pradesh, India



Impedance, Admittance, Reflex, Tympanometry, Reflectance, Absorbance


Estimation of the middle ear functioning is necessary for the assessment and management of the middle ear disorders. It is also crucial for deciding upon the management of hearing loss. Though very important for audiologists and otologist clinically, there are many misconceptions behind the scientific principle/rationale and confusions related to the terminologies and units used for the measurements of middle ear functioning such as acoustic impedance, acoustic admittance, middle ear reflectance and middle ear absorbance. Literature included in this review was searched from book chapters, instrument manuals, journal articles, monographs, scientific guidelines and standard specifications on the related topics. This review work threw light and eases understanding on the principles used by different instruments to estimate various measures of middle ear functioning. It will enhance understanding of the measurements and also of the relation between different measurements of middle ear functioning. Clinically, it will help professionals in analyzing results better considering the measurements variables (if present) and bring continuity in reporting the results of middle ear functioning.


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