Michael Gorga GORGA at BoysTown.ORG
Fri Mar 7 11:14:42 EST 1997

A recent posting on OAEs had a few errors in it that I would like to correct.  
First and foremost among these is the view that TEOAEs are not frequency
specific.  This view confuses frequency specificity in the stimulus with
frequency specificity in the response.  While it is true that TEOAEs most
typically are elicited by broadband stimuli (such as clicks), the energy in the
response is analyzed in the frequency domain.  If that response includes energy
around 2000 Hz, for example, that means that the region in the cochlea where
2000 Hz is represented is functioning (well, technically, outer hair cells are 
functioning, but lets not split "hairs").  An FFT on the response waveform
provides a highly frequency specific measure of cochlear status.

There are considerable data describing the clinical utility of OAEs, coming
from many different labs and clinics.  As examples, consider the work from
Miami (Lolnsbury-Martin, Martin, Whitehead), the work from Rochester
(Robinette), the work from Connecticut (Kim, Smurzynski and colleagues), and
the work from Minneapolis (Kimberley, Nelson), to name just a few.  If I may be
so bold, you may wish to consider the work from Omaha (Gorga, Stover, Neely,
Prieve) that looked at the relation between these measures in large samples of 
normal and impaired ears.  That latter set of work has been published mainly in

Yes, there are lots of things to understand about these measurements, but we
know as much (if not more) about test performance for DPOAEs then we do about
almost every other audiological test.  Even though other work needs to be done,
there is lots of information out there in the archival literature that
indicates the clear clinical utility of these measurements.

Michael Gorga
Name:		Michael P. Gorga
Address:	BTNRH
		555 North 30th Street
		Omaha, NE   68131
Telephone:	402/498-6604
FAX:		402/498-6638
e-mail:		gorga at boystown.org

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