Perfect Hearing with OHC Issue According to Otoacoustic Emissions Test

I have a dip in the otoacoustic emissions test between 4-6 kHz indicating some OHC damage. This could shed some light on origins of the tinnitus. My hearing is great for a 41 year old, including on the extended audiogram up to 12.5 kHz.

Has anyone had similar results? The audiologist said that this can happen with age or acoustic trauma. But she didn't rule out the possibility of ototoxic medication having an impact. So still in the dark, as many of us are when trying to understand etiology and prognosis.

 

What impact do you notice in terms of hearing quality?

Is it harder for you to understand TV, speech in noise, or understand what others are saying when you are not paying attention?

 

Honestly, I don't believe there has been any real effect on the quality as such. I listen to the TV a bit lower than before as I do not want it loud in any way and am generally fine with it. I did a speech in noise test in French - and still think I did pretty well (though I have always struggled a bit to hear clearly in a noisy place and seem to miss things in my own language and in French more than the average person).

I find it weird how my hearing can be great, but have some issues with OHCs at 4-6 kHz. I forgot to ask if I could have always had this.

 

4-6 kHz dip is usually a noise notch from noise exposure.

 

I haven't had the otoacoustic emissions test yet.

I was asking because my doctor told me that test can show a peripheral auditory neuropathy, which means the patient does well in a standard pure tone audiometric test but speech decoding and speech discrimination is poor or becomes poor over time.

Anyway, it seems peripheral auditory neuropathy cannot be fixed or treated...

 

The audiologist did not make reference to that, @Juan. I have seen that speech recognition may be affected by OHC damage, but it is not really an issue for me (certainly no change since tinnitus onset). As such, I would not put too much stock in your Dr's comments. Plus, I have just seen this:

"outer hair cells seem to function normally in people with auditory neuropathy... The hallmark of auditory neuropathy is an absent or very abnormal ABR reading together with a normal OAE reading. A normal OAE reading is a sign that the outer hair cells are working normally."​

So it looks like it's the ABR test that will prove crucial in determining this - not the OAE test.

 

I think there is no test to assess whether there is damage to OHC.

For instance, in a pure tone audiometric test, with very fine hearing, one can perceive a vibration, and hearing of course the tone at the right pitch.

With no hearing loss (as per clinical standards, less than 20 dB hearing loss is considered "normal") but a -20 dB reading on high frequencies (as high as 8 kHz, which is considered irrelevant as far as speech recognition is concerned) the pitch of a certain tone (high tones usually or very low tones) can be perceived differently from its absolute value, so the patient hears a sound but the perceived pitch is not right.

That is just an example of slightly altered hearing. Which would be the cause? The very mild dip of the audiometric reading (normal hearing) at high frequencies? The way OHC work? Other causes?

It is very hard to determine and assess hearing quality.

 

This is what the otoacoustic emissions test does as far as I am aware.

What I was referring to above, in your case of suspected auditory neuropathy, is the ABR test (in conjunction with the OAE test). If you did, indeed, have auditory neuropathy then, according to Dr Google, your OAE test will show no OHC damage, but your ABR test will produce an "absent" or "abnormal" reading (I have no idea what the ABR test consists of).

 

Otoacoustic emissions test is loud, from my experience. I don't recommend it.

 

Really? Do you have hyperacusis @kingsfan? I did not find the test I did to be loud at all - just a series of beeping sounds as I watched points being plotted on a screen and then verified (it appeared).

 

Thanks for your answer. I will research more about it.

 

This is exactly it. My OAE test showed no OHC damage, but my ABR was abnormal (wave I smaller than wave V, some latency issues, and cochlear microphonics where there should be none).

 

And what is the treatment proposed, if any, for those issues?

 

Unfortunately, there is no clinically approved treatment for auditory neuropathy (this umbrella term also includes cochlear synaptopathy, which is most likely what I have).

 

That's what I thought... thanks!

 

So malfunction of the synapses (in the cochlear or auditory nerve?) is suspected rather than malfunction of the stereocilia?

 

Yes, the signal is lost somewhere in the nerves. I guess technically you could have no proper signal when you have dead hair cells, but then OAE and PTA should show that.

 

I guess the clue is in the name ("neuropathy"), but I was wondering whether the mechanical functioning (or malfunctioning) of the hair cells could impact the delivery of the signal down the nerve.

Do you not have any hearing loss @Tau? Sorry, cannot remember your backstory though I know you are experiencing difficulty with this at the moment.

 

I do not have hyperacusis. My tinnitus was immediately and substantially worsened after an acoustic reflex test. I got a second opinion from another audiologist and was told acoustic reflex test should not be performed on a patient with tinnitus.

 

No worries, I have no pure tone hearing loss all the way to 16 kHz (it's all within 0-10 dB). But I do have neuropathy, and higher notes in music sound like trash. It was from listening to music at high volumes through my new headphones (up to 85 dB), then exposing myself to 110 dB 16 kHz sound for a few seconds, and finally an MRI.

 

@kingsfan - isn't that the Acoustic Reflex Threshold test?

 

Hey @Uklawyer, just wanted to advise I also had an ABR test which was normal despite those abnormal readings on my OAE. Also in my case I had another OAE done that conflicts with my most recent so I question the validity of that test in particular.