What Does a Notch in Hearing at 4 kHz Indicate?

I read some things on Wikipedia about our hearing, and it's said that a notch at 4 kHz could mean NIHL? Is this true? It's also stated that the higher frequencies will also be affected, but if you see my test results, it seems to only be 4 kHz where I'm having issues?

 

Hi,

I don't know how reliable Wikipedia is to be honest?

I did a quick search and found similar findings to you. NIHL commonly affects the hearing sensitivity in the higher frequencies; especially 4000 Hz, but can be between 3000-6000 Hz.

If you have a NIHL, then I would imagine the damage would be symmetrical, and the pattern of loss on a audio would resemble a hillside. The steeper the hill, the more the profound the loss.

What did your audiologist/ENT say?

 

That is true, a notch at 4kHz is indicative of noise induced hearing loss, just like with me. One of the audiologists said that this because we naturally amplify noises in this range with our ears because of evolution - when we are babies, it makes it easier for us to hear our mothers. I may have butchered that statement somewhat, but according to him, that is why when you lose hearing due to noise, 4kHz is most affected.

You would need an extended audiogram to see damage above 8kHz.

 

But would only 4kHz be affected? As you can see above, my hearing at 6 and 8kHz seems to be fine. I read on Wikipedia that higher frequencies will also show some loss, although I do need to do tests beyond 8kHz

 

I also don't know how accurate Wikipedia can be, but I don't think it's totally wrong either, considering people usually go there to read up stuff.

That's the thing. My hearing test shows a 30 dB loss at 4kHz, but 6kHz is fine.

I didn't read this part. So if I have NIHL, my left ear (blue line) should also show similar losses?

The person who conducted the test said "my right ear is poorer than my left". Both ENT doctors I saw said my hearing was okay. The first wanted to do a reflex test, but there wasn't an available slot for me to do it. I still haven't done it. I told the second one about it, but he wants me to have an MRI scan for my brain.

 

It is a common clue about NIHL. What's surprising is that you only have it in one side. Have you ever been exposed to music from one side only? (like being oriented next to a speaker such that only one ear is "aiming" at the speaker)

 

Does that mean that it is irrefutable evidence of NIHL, though?

As far as I remember, I've never really been in any such situations. When I first got T in 2015, I took care of my right ear. I've also been making calls with my left ear for years now. My T had gone away in fact. And I never used earphones beyond 60% volume for no more than 90 mins on avarage during the weekdays after that, up until I got this issue.

What I can say is that even before I got T in 2015, my left ear already seemed to hear better than my right ear. I (probably still do) would kind of concentrate the hearing in my right ear to make my hearing more equal, if that makes sense. Who knows if that contributed to my current issues.

 

No. Like I said, it's a clue, i.e. a symptom. A diagnosis is generally derived from a variety of symptoms. That doesn't mean that having a notch at 4 kHz is always NIHL.

If it doesn't fit, it doesn't fit. There's no point in forcing a NIHL diagnosis if you haven't been exposed to noise. There are other ways to lose sensorineural hearing.

 

I Have 15db on 3khz, is that hearing loss?

 

I'm not forcing a NIHL diagnosis. I really don't want it to be NIHL anyway, and I don't think NIHL is the cause when I think about the signs or symptoms I have.

One question about NIHL: Is NIHL supposed to present itself in hearing loss in both ears?

I also wonder if the cause is something that could just be affecting the hearing ability of my right ear, and would go away if I fix it...

 

What is 4 kHz in every day sounds even?

 

I don't think so. From what I've read, 15 dB should mean healthy hearing. And probably 20 dB to 40 dB means mild hearing loss.

 

No, it doesn't have to be symmetrical, hence my question about orientation of the head towards a sound source.

 

I don't know. Screeching brakes maybe?

 

screeching brakes would be much higher like over 10khz.

 

Well I'll have to think harder about this then.

I have some threads where I explain in detail some of the things I've gone through in my current episode. You could give the first post of the threads a read and tell me what you think.

https://www.tinnitustalk.com/threads/is-my-respiratory-system-causing-the-ringing-i-hear.32703/

https://www.tinnitustalk.com/thread...nt-my-hearing-reacts-to-certain-sounds.33011/

 

Hmm, I actually wonder what some common sounds for the different frequencies are. I know the sound of curse words being beeped is the most common example of 1kHz right

 

4K notch is industrial sound exposure, such as lawn mowers, leaf blower, passing cars, factory noise, and the like. My understanding is that it does not prove NIHL, but is suggestive of it from the sources above.

NIHL can be asymmetric depending on the exposure. In my case, I got T in one ear without the other as that was the side in retrospect that the weed wacker was on. I protect both ears the same at this point to prevent any further issues.

 

Is your affected ear hearing well?

 

Our heartbeat is that low?

 

Both ears hear fine, just the T is unilateral.

 

Yes and No. Frequency in Hz is used to tell the amount of occurrences per second. If our heart beats 60 times per minute, or once per second, then it beats with a frequency of 1Hz. The frequency of the sound that is typically associated with heartbeat isn´t 1Hz, it´s probably somewhere around 100Hz.

 

So your hearing test also came back positive then? Or do you have the 4kHz notch as well?

 

I don't have a 4k notch.

 

100 Hz would be 100 beats per second. Try to "picture" that in your head and squeeze a hundred beats into the next second.
Perhaps you meant 100 bpm? (which is about 1.7 Hz)
That would be more in-line with "normal heart beat" (which is between 60 bpm and 100 bpm at rest).

 

I meant that there are two different concepts here that can be both measured in Hertz. 60bpm or 100bpm, which more often used scale for heart rate, would translate to 1Hz or 1,7Hz if we wish to present it in Hertz (like it was done in the picture). By 100Hz sound I meant that a single beat sounds (using stethoscope or pulsating after heavy exercise etc...) like a kick drum which I believe has it´s first fundamental somewhere around 100Hz area if we were to look at it´s spectrum.

 

Ah you're talking about the sound we tend to think of when we think of a heartbeat, not the frequency of the heartbeat itself. Your clarification makes sense.

 

So it's your perceived hearing that's affected?

 

The hearing is fine. I have hyperacusis to the 4k frequencies when I get exposed to industrial noise. The other day, for example, was bothered by a leaf blower that was droning on from 5 houses away. It was not loud and <70 db, but still damn annoying and needed earplugs just to tolerate it outside while I had some work to do in my garden.