Electrocochleography (ECochG) is an auditory test that measures the electrical activity of the inner ear in response to sound. It is used to diagnose inner ear diseases such as Meniere’s disease, vestibular schwannoma, and acoustic neuroma. The test is also used to evaluate the function of the auditory nerve and cochlear hair cells.
The procedure consists of placing electrodes on the external ear canal and the mastoid bone behind the ear. A sound stimulus is then presented through headphones to the patient. The resulting electrical activity is then recorded. The results of the test are typically reported in terms of the auditory nerve compound action potential (CAP) and the summating potential (SP).
CAP is the electric potential generated from the auditory nerve in response to sound. SP is the electric potential generated by the hair cells of the cochlea in response to sound. Both of these potentials are measured in microvolts (μV).
The ECochG is a useful tool for diagnosing inner ear diseases and disorders. It can also be used to measure the degree of hearing loss and to determine if there is anatomical damage to the inner ear. Additionally, it has been used to evaluate the effects of certain drugs and to assess the efficacy of hearing aids.
ECochG can be performed alone or in combination with other auditory tests. The results of the test are typically reported in terms of the auditory nerve CAP and the SP. While the test may provide useful information, it should not be used as the sole basis for diagnosing or treating a medical condition.
References
Gates, G. A., & Mills, J. H. (2007). Introduction to electrocochleography. Seminars in Hearing, 28(1), 51–58. https://doi.org/10.1055/s-2007-964914
Masterson, B. J., & Nageris, B. I. (2014). Electrocochleography: An overview. Audiological Medicine, 12(2), 78–83. https://doi.org/10.3109/16513890.2013.851704
Rajguru, S., & Whiten, E. (2017). Use of electrocochleography in clinical practice. Journal of Clinical and Diagnostic Research, 11(6), BC01–BC04. https://doi.org/10.7860/JCDR/2017/29220.10231