presence of otoacoustic emissions in individuals with h.i.

[Allison M. Scott]

I recently read an article in "European Archives of Otolaryngology", Vol. 
250. pgs 366-368 which is of great interest.  A 6-year-old boy with 
unilateral deafness was found to have otoacoustic emissions in his deaf 
ear.  A full test battery showed a flat ABR, Neg ENG results, Neg CT 
scan, and a normal neurologic work-up.  Upon electrostimulation of the 
auditory nerve, the young boy consistently reported a hearing sensation.  
The authors of this study determined that there was a large enough 
population of OHCs to cause an OAE, and an IHC disorder is to be expected 
due to electrostimulation results.  

Another interesting article can be found in "Journal of Speech and 
Hearing Research" Vol. 34, pages 379-385.  This is also a case study 
about an individual with severe hearing loss who has otoacoustic 
emissions.  Once again, these OAEs in the presence of severe hearing loss 
are attributed to some surviving OHCs but damaged IHCs or nerve fibers.  
The authors of this study go on to discuss several other studies that 
found otoacoustic emissions in people with severe or profound hearing 
loss.  They criticize these studies for lack of adequate controls and 
suggest that the measured OAEs may merely be artifacts caused by 
nonlinearities of the measuring system or improper fit of the probe tube 
in the ear canal.  

This brings to light the need to use adequate controls when using OAEs in 
daily clinical applications.  I still reserve a healthy skepticism about 
the use of OAEs beyond as a screening tool.  Is anybody else having 
trouble warming up to clinical use of OAEs?