Pain Hyperacusis in Relation to Acoustic Shock & Synapse Disconnection

Now I see, I went backwards there. I don’t have stabbing pain. Never did. I have the burning pain and that’s it. If I have a noise assault, my ears don’t actually do much in the moment but when I wake up with more easily triggered burning.

Now I definitely have cochlear damage because I have tinnitus and hidden hearing loss. But other than that I just have burning pain.

It makes me think that many sufferers will need more than one treatment to help all their symptoms.

 

If you know you have hidden hearing loss then I wouldn’t be surprised if OTO-413 helped you. Unless all forms of hyperacusis come down to the new maladaptive synapses that attach to OHCs after loud noise.

 

It's weird I have never had immediate pain after a noxious sound - always the delayed burning sensation that is prolonged and long-lasting.

 

What would be the likelihood that the reason for pain hyperacusis to happen is because of missing IHCs and OHCs rather than synapses? For our case it would be better if the reason for pain hyperacusis to happen is because of these missing hair cells. I still believe in restoring hearing input will stop the pain from happening.

 

Does it stay in your ears or does it travel throughout your face?

 

Well the only potential mechanisms I’m aware of are ATP leakage and maladaptive synapses both stimulating the type II afferent nerve fibers. Neither of which would be directly affected by regrowing hair cells. The support structure regeneration that comes along with hair cell growth might help if you have a lot of dead hair cells, not just damaged synapses/hidden hearing loss. But if you don’t have noticeable hearing loss on an audiogram then I doubt it will do much compared to something like OTO-413.

 

Before getting hyperacusis I noticed that my right ear heard sounds less when listening to music and now my right ear sounds louder than my left. That’s why I’m wondering how much do hair cells play a part in pain and loudness hyperacusis. I just hope when the hair cells start regrowing it will let the brain know to turn down the volume to stop making things seem loud and stop the pain.

 

It used to be ears and face. Kind of a mixture of both.

 

This is why it will be interesting to ever discover where the ATP leak is coming from, because if it's coming from dead OHC support cells then it stands a good chance of being fixed, but if it comes from somewhere else as well, or entirely from somewhere else (such as gap juctions), then fixing the hair cells and synapses might give you back really good hearing but your mechanism for pain could still be in place. Even if the excess ATP leak got fixed assuming it was down to support cells that are now restored, the type IIs would still be sensitized so it would be a matter of does regular amounts of ATP still stimulate them? And finally if not then do they desensitize over time?

If FX-322 wins the race against the research it will hopefully tell us more about this anyway.

It's weird isn't it, as similar as the symptoms are for noxacusis from a broad view, they have so many little deviations and nuances at a more detailed level for each sufferer.

 

If dead OHCs are causing pain hyperacusis then FX-322 should definitely help us but the likelihood of it being something else other than IHCs or synapses is quite low but still possible.

 

So, are our brains just fundamentally broken?

Subcortical and cortical responses are enlarged in tinnitus patients with hyperacusis compared to those without hyperacusis

Highlights

- Higher (sub)cortical sound-evoked activity is a specific marker of hearing loss

- This is true even in the presence of hearing loss and tinnitus

- The increased cortical responsiveness is not restricted to hearing loss area

- Increased loudness percept relates to neural gain in central auditory regions

- Reduced response to tinnitus frequency compared to no hyperacusis

Abstract

Hyperacusis, hypersensitivity to sounds of mild to moderate intensity, has been related to increased neural gain along the auditory pathway. To date, there is still uncertainty on the neural correlates of hyperacusis. Since hyperacusis often co-occurs with hearing loss and tinnitus, the effects of the three conditions on cortical and subcortical structures are often hard to separate. In this fMRI study, two groups of hearing loss and tinnitus participants, with and without hyperacusis, were compared to specifically investigate the effect of the latter in a group that often reports hyperacusis. In 35 participants with hearing loss and tinnitus, with and without hyperacusis as indicated by a cut-off score of 22 on the Hyperacusis Questionnaire (HQ), subcortical and cortical responses to sound stimulation were investigated. In addition, the frequency tuning of cortical voxels was investigated in the primary auditory cortex. In cortical and subcortical auditory structures, sound-evoked activity was higher in the group with hyperacusis. This effect was not restricted to frequencies affected by hearing loss but extended to intact frequencies. The higher subcortical and cortical activity in response to sound thus appears to be a marker of hyperacusis. In contrast, the response to the tinnitus frequency was reduced in the group with hyperacusis. This increase in subcortical and cortical activity in hyperacusis can be related to an increase in neural gain along the auditory pathway, and the reduced response to the tinnitus frequency to differences in attentional resources allocated to the tinnitus sound.

 

Could this mean FX-322 might work for hyperacusis? If we can restore hair cells and synapses, wouldn’t this decrease the neural gain?

 

Hyperacusis Research posted a link to this on their Facebook page:

From a Hyperacusis Patient to Audiologists: My Advice for Better Patient Care

 

Hi! I have been reading your posts and I want to ask you about my ''tinnitus situation'', maybe you can shed some light on it.

I have been having severe fluctuating tinnitus for 2 years now. Everything started with a clogged ear due to an external fungus infection. They treated the fungus infection with antibiotic drops, but my ear stayed clogged for over a month. I'm guessing now there was inflammation which needed medication. The doctors gave no medication and they were keep telling me that the ear will recover by itself.

So a month into that inflammation, 2 years ago, my tinnitus started. Same time both ears, even my fungus and clogged stuff was in my left ear only. In the beginning was moderate but over a year started to fluctuate from moderate to severe and very severe one. When in noisy every day situations (traffic road, talking with more people, average noisy restaurants, driving etc.) my tinnitus will spike but subside after some hours, a day. In the second half of the first year with tinnitus I had regularly moments, once a month or 3 weeks apart when I was caught in conversations about my situation and, trying to explain to the others, I used to raise the voice or even shouting at times, out of frustration that I wasn't understood. Half an hour, more or less, I can't exactly say that now. Since then my tinnitus started to fluctuate with those severe and very severe moments, day, days. Really irregular.

Now I'm wondering how could that happen as long as I didn't have any history of loud noises. No other history of medication, TMJ, depression, other diseases, nothing.

Could that clogged stuff affected my inner ear? My both audiograms are normal up to 16,000 Hz, although the recognition of words in a noisy background is bad. This when I had the tests at the ENT clinic. Otherwise I have no problem of understanding what someone say in a noisy environment. And can be that have always been my situation as I never had problems with my ears so wouldn't check on them at an ENT department.

On the other hand my previous clogged ear never regained its normal shape. There is almost all the time pressure and when there is more noise , like talking noise, or some physical activity, tends to shrink itself. Then I have some pain, but is more like a pressure pain. Also there is almost all the time some clicking, more code type tinnitus, humming noise. When my tinnitus is very severe my bad ear is spinning inside and there is a jet engine tinnitus in both ears. Like blowing wind through a metal tube.

According to the tests that I did at the ENT clinic the tubal pressure in my bad ear is very low, my eardrum vibrates low than a normal one. No ETD problems as far as I know, no symptoms of it.

I keep wondering if my tinnitus can be due to this bad pressure and middle ear muscles. As I have read those muscles, when acting up, can give all the clicking and spinning noises I have said above. Or that clogged stuff irritated the trigeminal nerve causing tinnitus? But can this give a tinnitus which acts up when in noisy environments? Some say is reactive tinnitus and some say there is no such thing, is just hyperacusis.By the way I have no pain or sensitivity to noises, only my tinnitus going up.

I' m really trying to understand if this ''acting up'' that always happens in noisy environments is due to middle ear muscles which can play havoc with my whole auditory system in those moments (there can also be echoing sounds, crickets all over my head). But this is also happening without noise, as I had said my tinnitus fluctuates.

Thank you very much for listening to my story. Maybe you have an answer for me as I'm trying to figure out what it is and where to go, what treatment to expect will give relief of it or cure it.

 

Hey man. I'm signed up to have my Tympani muscle severed. Do you think the surgery made you worse? or just didn't help? My Tympani spasms are really bad. Talking, yawing, burping, stretching, coughing, and all outside noise makes it spasm. Sound doesn't cause me too much pain just some residual burning in my left ear, but tinnitus is severe.

 

It did not do anything, good or bad, for me. My problem is within the cochlea.
You should get relief from the symptoms as you prescribe them. I didn't have any of that. Just extreme pain.

 

Does this seem relevant to this conversation?

Within-Subject Comparisons of the Auditory Brainstem Response and Uncomfortable Loudness Levels in Ears With and Without Tinnitus in Unilateral Tinnitus Subjects With Normal Audiograms

 

God. Let's try to unwrap this, shall we?

I only have a couple of paragraphs here to draw any conclusions, but let's see what we can infer.

So firstly, they compared patients with tinnitus and without tinnitus, but they made sure that both groups of patients had "normal symmetric hearing thresholds". This is academic speak for no audiogram differences, but as we know, audiograms don't reveal synaptopathy issues. Major red flag No. 1.

With this in mind, let's look at what they measured. They found that between these two groups of patients, there was no difference in the V/I ABR wave ratio. For those unfamiliar, wave V supposedly comes from the upper brainstem and wave I comes from the SGNs in the cochlea. In other words, wave V measures centralised changes while wave I measures peripheral changes.

So they're suggesting that patients with tinnitus but without hearing loss (where hearing loss is wrongly indicated by the results of an audiogram) do not exhibit any kind of cochlea synaptopathy, because otherwise they would observe changes in this ratio - specifically Wave I. But let's return to my point above: audiograms are not a measurement of cochlea synaptopathy, so it's entirely possible that both groups had synaptopathy or both groups didn't have cochlea synaptopathy, hence the no "significant differences".

Let's also consider the following quotes from this study:

"High-frequency cochlear synaptopathy profiles ... tended to increase the Wave-V/I ratio as a consequence of smaller Wave-I amplitudes along with constant Wave-V amplitudes"

So this quote is effectively alluding to what the researchers of the study in question were looking for: a smaller wave-I amplitude in the tinnitus ears than the non-tinnitus ears as a sign of synaptopathy. But it also specificies that this behaviour is, theoretically, viewed in high-frequency cochlea synatopathy profiles. Unfortunately the synopsis of the study in question doesn't say what frequencies they were measuring, but it's possible that they may have only been measuring frequencies on the lower end, in which case, one wouldn't see a change in the ABR wave ratio. - Red flag No. 2.

Let's also consider this quote from that same study:

"Under the assumption that the model is realistic, and cochlear synaptopathy is expressed in a frequency-specific manner similar to audiometric loss, a general trend of increased Wave-V/I ratios is seen to go along with smaller Wave-I amplitudes."

This is why what frequencies they were measuring are so important. The current models assume that cochlea synaptopathy "mirrors" audiometric loss i.e. hair cell loss, but we know this not to be true either! Red flag No. 3.

Having said this, I do find their uncomfortable loudness levels tests to be really, really interesting for those of us with hyperacusis. These are not patients with hyperacusis but with tinnitus, yet they were able to show a clear difference of approximately 14 dB (on the low end) between volume tolerance levels. This would suggest that tinnitus does actually go hand in hand with some kind of very mild-hyperacusis. Anecdotally speaking, I know that there are many on here who have tinnitus but not hyperacusis and do not have the same tolerance to sound as they used to pre-tinnitus, even though they don't have hyperacusis as it's clinically defined - intolerance to every day sounds. As someone who has had tinnitus for 13 years and hyperacusis for only 8 months, I can also say that before I developed hyperacusis my general tolerance to sound wasn't the same as it was when I first developed tinnitus.

I have serious questions about the reliability of their results given how they "measured" cochlea synaptopathy (through an audiogram). But it would be interesting to me to know that, if they haven't measured cochlea synaptopathy properly and we are seeing volume tolerance decreasing in tinnitus ears, then the very opposite of what they're suggesting is true: cochlea synaptopathy does contribute to tinnitus and hyperacusis.

EDIT: can someone get access to the full article? I'd love to read it and get a better insight here.

 

This study is very similar to the one from 2016(?) were they also measured LDLs between people with and without tinnitus. The tinnitus group had worse LDLs with a difference of approximately 11dB. I know there is a thread about that study somewhere on Tinnitus Talk but I can't find it.

EDIT:
I found it:
https://www.tinnitustalk.com/thread...nts-with-normal-audiograms.15819/#post-186983

 

So if the trigeminal nerve is sensitized and that’s what causing the pain, would a trigeminal nerve block alleviate the face pain of noxacusis, or is there something I’m missing here?

 

Well, if I recall correctly, there isn't any direct evidence showing that this process sensitises the trigeminal nerve specifically.

All we know is that the type II neurons in the cochlea become sensitized from ATP leakage. Now, from this point on and how the trigeminal nerve is involved is anyone's guess. I do remember coming across one study - and only one study - that suggested the trigeminal nerve may in fact innervate the cochlea in some way (I think previously it had never been shown to be the case). If this is the case, perhaps there is some pathway/mechanism for the type II afferent sensitisation to manifest upwards into other areas.

There is also of course anecdotal evidence of anti-convulsants helping people with hyperacusis, but I remember reading somewhere that they only work for 1/3 people and in those 1/3 the improvement was measured at around 30%, which makes me question how much the trigeminal nerve is at play here.

It is well known that referred pain is also a thing - experiencing pain in one area when the problem is actually in another part of the body. You see this all the time in sports-related injuries, particularly in the back, neck and shoulders.

I think trigeminal neuralgia is a secondary symptom of hyperacusis because clearly not everyone experiences these types of symptoms.

 

Interesting stuff here, but I should mention that that pain metric with nerve pain meds you showed was referring to its efficacy with nerve pain in general. I read the same article lol, it was a good piece.

An MD Summary of the 2016 ARO Hyperacusis Symposium

Yeah, I finally got into seeing a neurologist and she’s going to try Gabapentin with me, I took some before and it didn’t do much but I didn’t have enough to give it a fair shake. I’m hoping it works because, for me, the facial stuff is by far the worst part.

 

Yes, they said that about Lyrica (Pregabalin). It's supposed to treat nerve pain. So whether the trigeminal nerve is involved or not should not matter. We are talking about NERVE fibers within the cochlea.

I'm up for another SGN blockade soon btw, using Botox this time. I'm not holding my breath it will do anything.

 

You're right, thank you for pointing that out and reminding me where I read it!

I also suffer terribly with the facial pain so please let me know how Gabapentin works for you!

 

The thing that makes me question the trigeminal nerve involvement is the experiment that Jaime Garcia-Anoveros ran where he found that the trigeminal nerve does not react to loud/damaging noise, and that the type 2s were involved instead.

I wonder whether it could be a form od referred pain or secondary hyperalgesia where the surrounding nerves become activated. It wouldn't surprise me.

 

When are you getting SGN blockade done?

And yeah, there are tons of reports of hyperacusis patients getting helped with various anticonvulsants.

 

I will. The only thing that I’ve found that helps so far is Phenibut. 2 grams.

Well isn’t the theory that it’s the middle ear muscles are somehow irritating the trigeminal nerve, so it wouldn’t be the nerve itself reacting but the middle ear reacting and irritating the nerve?

I am more of a social science person, so this stuff kinda confuses me and I appreciate anyone explaining it. You, 100Hz, FGG, etc are so smart.

 

@grate_biff I think there's been a bit of a misunderstanding. The original question by @Born To Slay concerning the trigeminal nerve had to do with hyperacusis-induced facial/jaw pain specifically, not hyperacusis ear/cochlea pain. I wasn't saying that Lyrica or Gabapentin wouldn't work for the ear-related hyperacusis symptoms/pain, I was simply saying it was open to debate whether it would specifically help with the facial pain (which not everyone with hyperacusis experiences), because if the trigeminal nerve doesn't innervate the cochlea then either we have a case of referred pain or a different mechanism entirely.

 

I think a lot of these nerves are in very close proximity to each other so I wonder if there's some sort of cross-talk between them that occurs.

I'm also more of a social science person, I have no scientific or mathematical background at all! I basically just regurgitate what the researchers and the information on Hyperacusis Research say lol. I'm always impressed by the knowledge and intelligence of the members here, you included.

 

A good amount of people who have trigeminal neuralgia, “type 1” trigeminal neuralgia especially, mention that loud noise sets off their pain.

I personally do believe the middle ear muscles have a lot to do with it. Perhaps a lowered reflex due to cochlear damage, in turn making the middle ear muscles more sensitive and overworked and irritating the nerve somehow.