Re: Estimating OHC/IHC Loss Proportion in Humans using DPOAEs

[Anders Tornvig Christensen <atc@xxxxxxxxx>]

Dear Jeff,

This is a very interesting and very ambitious goal for OAEs. Just think of the experiment: You need a detailed hearing history of people with different types and degrees of hearing loss, then you need them to undergo surgery, making them deaf (or wait for them to pass away), to eventually count their remaining hair cells.

DPOAEs come from two points on the basilar membrane. Those points are distributed over a number of hair cells, at the places depending on the individual place-frequency map of the cochlea. The  transmission of sound between the ear canal and the points of OAE generation in the cochlea varies as well. We can't determine this transmission in the individual.

Regarding the behavioral methods, remember that they take into account the entire auditory system. You can still hear via the passive mechanics of the cochlea, if you have just inner hair cells and no outer hair cells, although at increased thresholds and decreased frequency tuning. There's also such a thing as off-place listening, so you can have no hair cells in one place on the basilar membrane and still hear something at the frequency corresponding to that place via the neighboring places.

I hope this outlines some of the challenges.

Finally, a few authors I think you may find interesting (although there's no off-the-shelf method to use):
M Mauermann et. al, the 1999 works in particular, about selective hearing loss in the two places of DPOAE generation.
C Halpin >2009, he actually counted hair cells to investigate the benefit of hearing aid fittings.
C Bergevin (and C Shera) has investigated cochlear tuning using phase measurements of SFOAEs.
BCJ Moore has defined the term "dead regions" in the cochlea and developed behavioral methods for estimating tuning to find them.
DM Mills combined audiometry and DPOAEs for differential diagnostics of cochlear damage. 2006 paper in particular.


Good luck!
Anders

I'm a PhD student in OAE techniques at Aalborg University, Denmark.

________________________________________
From: AUDITORY - Research in Auditory Perception [AUDITORY@xxxxxxxxxxxxxxx] on behalf of Jeff Bruce [jeffbruce@xxxxxxxxx]
Sent: Tuesday, April 09, 2013 8:59 PM
To: AUDITORY@xxxxxxxxxxxxxxx
Subject: [AUDITORY] Estimating OHC/IHC Loss Proportion in Humans using DPOAEs

Dear auditory list subscribers,

I am searching for any publications which document the application of distortion product otoacoustic emissions (DPOAEs) as a way of estimating the proportion of outer/inner hair cell (OHC/IHC) loss in humans with hearing loss.  I have performed several Google Scholar searches but can only seem to find methods applied to other animals.

Alternatively, if you know of any other behavioural methods to estimate proportion of OHC/IHC loss, such as documented in the Journal of the Association for Research in Otolaryngology by Lopez-Poveda and Johannesen (2012), I would very much appreciate hearing about such techniques.

Thank you.

Note: the title of the paper I referred to is "Behavioral Estimates of the Contribution of Inner and Outer Hair Cell Dysfunction to Individualized Audiometric Loss"

--
Jeff Bruce, Graduate Student/Teaching Assistant
McMaster University, Psychology Building, PC320
Work: 905-525-9140 x24832