Related Experiment Videos
Brief report: the cochlear microphonic as an indication of outer hair cell function
1Auditory Physiology Laboratory, Northwestern University, Evanston, Illinois, USA.
Ear and Hearing
|March 29, 2001
Summary
The presence of a cochlear microphonic (CM) does not rule out outer hair cell dysfunction. Auditory neuropathy diagnosis requires further testing beyond CM presence alone.
Area of Science:
- Otoacoustic Emissions
- Auditory Neurophysiology
Background:
- The extra-cellular cochlear microphonic (CM) is traditionally linked to outer hair cell (OHC) function.
- A present CM with an abnormal auditory brainstem response (ABR) has led to auditory neuropathy diagnoses.
Purpose of the Study:
- To re-evaluate the assumption that a present CM excludes OHC dysfunction.
- To investigate the generators of the CM recorded from the round window.
Main Methods:
- Review of animal studies on CM generation.
- Analysis of the relationship between CM, OHC pathology, and otoacoustic emissions (OAEs).
Main Results:
- Animal studies indicate CMs recorded from the round window are primarily generated by basal cochlear cells.
- The presence of a CM does not exclude OHC pathology.
Conclusions:
- OHC integrity cannot be solely inferred from the presence of a CM.
- Absence of otoacoustic emissions in cases with CM is consistent with OHC dysfunction.