Advances in the Neurobiology of Tinnitus and Hyperacusis

Weird thing is this article states that those with cochlea damage can show hearing loss, or no hearing loss at all. This seems to refute all theories about inner and outer hair cell damage.

 

@lapidus @Lisa88 You have to remember audiograms don't measure all hair cell damage. Audiograms only measure hearing thresholds. I am not an expert in audiograms. Other people on this board know far more, especially ATEOS. But researchers do agree that for most people some degree of hair cell damage has occured--even if this damage does not show up on an audiogram.

Here's a recent article on hidden hearing loss:

http://www.sciencedaily.com/releases/2014/05/140507142804.htm​

That article was also discussed on these threads:

https://www.tinnitustalk.com/threads/new-theory-of-hearing-loss-tinnitus.4738/#post-46598​

https://www.tinnitustalk.com/threads/am-101-tactt1-results-released.1994/page-23#post-39689​

And here's the link to a 2011 abstract on hidden hearing loss:

http://www.ncbi.nlm.nih.gov/pubmed/21940438​

Now, hearing loss is not the only reason people get tinnitus. Brain injuries, such as concussions, may also cause tinnitus. But some type of hair cell damage is behind most cases of tinnitus. That's all I'm saying.

 

@jazz. Thanks for posting the article. There are so many different cases for onsets of t. Brain injuries, orgasms, overload of CNS ... and many scenarios within the latter. Nothing is for sure with t. Cochlea damage is inner ear only. But the hearing apparatus extends into the central auditory cortex, where hyperactivity/neuron overfiring is often characterized with t. I was lucky enough to speak to Dr. Steven Cheung, ENT and head researcher on Deep Brain Stimulation and t at UCSF. He has seem many cases where his work with both brain activity and t has led him to the conclusion that it is not inner ear/cochlea damage but more likely origins within the auditory cortex and CNS.

 

you've had T since 1999 with no HL?! Both ears?

 

Interesting. Yes I've redad that article about hidden hearing loss and it scared me. Let's say you fix the brain part (over active neurons and whatnot) the hair cells will still be damaged but not be able to produce T? I could totally live with that.

@Jay M
Yes, I don't think that's uncommon to have T with no hearing loss.

 

I would be completely fine with hearing loss w/o T!
So you're saying it's common for people to have T with no hearing loss?

 

Yeah, from my understanding a lot of people with T have no hearing loss.

"However, in many cases tinnitus accompanies hearing loss. Because hearing loss can be caused by noise damage to the ear, an individual can get both hearing loss and tinnitus from noise damage. However the two do not always occur together. There are many who have no measurable hearing loss but have tinnitus."

From ATA http://www.ata.org/for-patients/faqs

But if the theory about hidden hearing loss is correct, I may have some of that.

 

I'm going to look for some articles about this. Everything I've read argues that most cases include cochlear damage; but it would be interesting to see if anyone did a meta-analysis of tinnitus etiologies to ascertain what percentage are cochlear induced and what percentage are from other factors.

Very impressive! Where you considering a procedure?

 

I am at 8 months from onset. The DBS study requires a year or more. It is an invasive procedure placing electrodes at the basal ganglia of the brain as a gating system/inhibitory response to the overfiring of neurons from excitatory neurotransmitters. I would do it if I were eligible

p.s. My t was triggered through local anesthetic lidocaine administered at the same time as a migraine. Sudden onset. Cheung believes that a brain chemistry change triggered t (probably somewhere in the central auditory cortex), the brain's central system where the auditory nerve leads. I was measured on audiograms, high frequency audiograms, OAE's and a host of other tests all within good and normal hearing thresholds, even for someone younger than my age.

I think unless the experts come up with a common ground for t, which has proven hard to do given its many different onsets and reactions to treatments, cochlea damage as a conclusive scenario for most cases cannot stand.

 

Just an added clarification to my note: If hearing was the only issue, which I don't believe is the case in many neural based studies, almost anything can impede signal in the hearing apparatus - from a dampened bone in the middle ear, to displacement of tissue or muscle by the auditory nerve, to changed brain chemistry in the central auditory cortex. Endless mechanisms at play here. Hearing extends far beyond the cochlea/inner ear.

 

@Lisa88 Yes, I am familiar with the DBS study. It will be exciting to follow it. I am sorry you weren't eligible. I confess to not being brave enough for an implant, but if my tinnitus were severe enough I might consider it.

The TRI has a flow chart on multiple tinnitus etiologies that affect treatment strategies. Nearly all tinnitus studies look at very few variables--such as age, gender, laterality, and tinnitus duration. Few breakout out specific tinnitus etiologies--but what little studies have been done--suggest that differences may affect potential treatment modalities.

Here is the TRI flowchart:

http://www.tinnitusresearch.org/en/projects/flowchart_en.php​

Here are two good articles on trauma-associated tinnitus:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3458888/

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3261792/​

We definitely need more research investigating tinnitus etiologies, but, unfortunately, tinnitus is so underfunded that just understanding the mechanisms of noise-induced tinnitus will be a long process.

 

I think hearing loss amplifies T. No hearing loss and people still get T just proves it's not just in the ears.

What if the auditory nerve is shorting out like an electrical wire? What happens when it has to much voltage running through it? The wire burns out except our wires try and sometimes heal although not good as new. Sound is converted to "electric" signals from the cochlea and sent to the brain. Damage occurs when the auditory cortex receives to much sound (in the form of electricity) at once or to much over a long period of time. The auditory cortex starts to short circuit bc it cant process the power surge or is overheating from long term use w/o cool down. ....just a wild thought.

 

Ha, ha...Does anyone have time for a job?! No wonder I don't get to my "must read threads" list (like stem-cell regeneration, LLLT, etc., etc.). Just this thread has had enough in it to keep me wondering and puzzling all day between chores and I haven't even clicked all the links! And yeah I'm "retired" - c/o T and H mainly I guess.

Anyway, it's clear that the current tinnitus and hyperacusis functional/causality models have a number of sort of 'self negating' facts...like tinnitus without auditory damage; or tinnitus cessation once implanted cochlea turned off; etc. Even the fact that one can have tinnitus onset without any relation to a "hearing trigger" (like loud sound), or direct audile nerve impingement (like acoustic neuroma, or that bone thing)...is just plain goofy really! Like there's all these possible causes and potentialities from almost pure "brain makeup fantasy" doing it's own thing creating a phantom sound, to clear and present "physical" auditory damage...IED impact for example, that obliterates inner ear hair cells, etc.

This is one tough nut to crack, and I have to agree with @lapidus :
The thing is that the theories that pop up here on this board by "laypersons" like us aren't that bad at all. Some stuff I've seen here make total sense to me. I would not underestimate the scientific discussions going on here on this part of the site. Discussions like these may even play a crucial part in solving this torturing puzzle.
I sure have deepened my understanding (and confusion too) a lot just in the last day c/o this discussion. And if I was a bona fide Tinnitus researcher or start-up wanting to make a billion with a "cure", I would be surfing this site big time for very wide, wise and provocative ideas about where to go and what a wild beast this is we are dealing with.

Hey @Lisa88 I'm a few hours north of SF so was going to seriously consider the new deep brain stimulation trial but am ineligible as have H. for one. I think there was something else too, like no benzos or ??? (I take Klonopin for sleep...which doesn't work, but not easy to drop!) Hopefully some other trials will come to SF area in future (I bet Autifony will be swamped!!!).

Good luck...and again provocatively mind bending thread here...In a good way!

Zimichael

 

To be brutally honest I had a huge smug smile on my face reading this as it confirmed my belief on T and H and ive been saying it for years,I dont for one second believe that T and H are related to haircell damage,I believe haircells involvement is minimal at best and Ive for a long time had the belief that this was auditory nerve,brain caused.I believe that the cochlear haircells is not where it all begins but the next step up,auditory nerve fibers.Haircells dont emit sound to the brain they are just a receptor and pick up a frequency for the auditory nerve to lay to the brain,haircells are just a glorified eardrum in my opinion and haircell regeneration for those of us with no hearing loss will prove worthless.That said its not all in veine as the University of Sheffield I believe is working on auditory nerve regeneration as they believe haircell regeneration will be worthless if this is not mastered first so alls not lost.Also Lapidus from my admittedly quick read of this article my view of this in simple terms is this,picture a wire going to a tv the wire being the auditory nerve and the tv being the brain,imagine a plain white screen,imagine stepping on the wire and the screen began to flicker uncontrollably,this is T,now imagine stepping on the same wire again but this time the screen gets brighter and brighter,this is H.Because the input to the tv has been compromised the tv cant remain at normal function as its input i.e the wire and its electrical currents have been interrupted and is now receiveing unaccurate signals from the wire screwing up the tvs lovely plain white screen,its the same with the auditory nerve and brain rather a bit more complicated.Its the best analogy I can think of when you compare it to someone with auditory nerve compression whether it be from an acoustic neuroma or other health reasons,their nerve is being pinched much like the wire and their number one complaint is T and H but funny enough once the pinch has been removed so has the T and H.

 

@bill 112 But who is stepping on the wire and how/why if there has not been any "obvious" reason for that??? I say that tongue-in-cheek of course as who knows what is causal in T that manifests without trauma or "out of nowhere" so to speak.
Also, I'm presuming that you think 'loud sound' trauma (as easiest example), or loudish exposure over time, somehow gets flipped back through the system c/o the hair-cells and the "stepper-on'erer" stamps foot down. It would be instant overload and a big scrunch right away in the explosion example. With long term, less loud exposure, then the stepping on slow and almost secret.

Then there is ototoxic damage...A whole new damage stepper-on'erer! And so on.......................

By the way, not really expecting an answer here, just musing out loud. But whatever - let's shoot the bastard stepping on the wire!!!

best Z.

 

Well if you think about it realistically. Your brain creates every sound you hear. For instance, the sound of your computer is actually a vibration that's being turned into sound by your brain. I'm pretty sure many people including you understand this. It's perfectly clear that whatever part of our brain responsible for creating that frequency is mis-firing whether it be from any damage to the ear from noise otoxicity or damage to the brain.

 

Our bodies run off electric impulses powered by the brain and without it we would not be alive or function properly. Does that make us complex organic robots?
Ototoxicity might be like throwing or dripping water on electrical equipment and shorting out parts of the system. Think about it. Meds are toxins and do not target specific ailments in the body when you take them. They flood the body and bc of this, ototoxicity is an undesirable side effect but the feel good part of the drug is a desirable side effect. The reality of this is we poison ourselves to feel better. So rather than thinking what seems like all meds can effect the tiny hairs inside the cochlea; those meds taken in small or large dosages flow through out the entire body over a period of time disrupting multiple nerve functions temporarily or permanently. When drug plasma levels are up it's like a steady rain or flash flood of toxins. Our body is always naturally removing toxins (chemicals, virus', etc...) but it becomes "bailing water out of a leaky boat" when we are taking meds. This is why we have to keep taking meds daily at certain dosages. The body doesn't want it even if it makes us feel better, its not good for us. The immune system is eventually over burdened and the levee breaks resulting in nerve damage such as Tinnitus.
Now that I'm wondering about it, is T a form of brain damage?

 

@Kimbo Slice & @Jay ...Yeah I have no issue with those things or the way you are describing them [Brain creates all sound in the end; and otoxocity is from 'add on' deleterious effects of a med that happens to also be damaging - for some people/bodies, in some places - like auditory pathways, etc.]...I guess I'm focusing much more specifically on the details of all that, as in the end those details are going to be what gets the big Kahuna banana, and what the researchers are going to have to get straight in relation to 'cure design criteria'.

OK, just for the exercise here...simply speaking everything pertinent to our awareness could boil down to "consciousness". I'm not referring to autonomic nervous system gear like digestion, liver function, heart beating etc., etc. With regard to relevance for us as humanoids those only tend to become "conscious" when they go wrong, or hurt, or make trouble.
Sound on the other hand, is a double trick, as we hear it whether we like it or not if it's there...yet with changes in 'consciousness', it can do everything from wig out and do double flips (yeah I admit I did do a few LSD trips 44 years ago at college), or plain be screened out and as good as 'unheard' (like folks living next to a freeway don't notice the cars...NEVER possible for me by the way, even as a nipper!).

OK, so what??? Is this guy (me) just head tripping here???

Maybe...but there is stuff in the research and article that started this thread that seems very, very pertinent to me to get right, or at least understand, if this T thing is going to be beat and we are going to get a cure in my lifetime. Hell I've already been waiting over half a century!
I mean think about it...It's almost like the explanation models for Tinnitus are grouped into three camps (as I understand it), no matter what the causal agent. (Assume I am also talking about H. but leave that out as it's almost more trippy complex than T.):

1. That Tinnitus is totally a "brain thing" - as in main brain area - as in where consciousness resides - as in where associations and neural software comes up with the results to awareness - etc.

2. That Tinnitus is a neural damage or overload thing - be it caused by damage to auditory hair cells or efferent nerves to the auditory cortex (and God knows how many other areas!) - that this damage or aberration in "hardware" screws up functioning and sends goofy messages to the software team that then decides to post it into the neural net ("consciousness") as what we know as Tinnitus!

3. That Tinnitus is a multi-faceted combo beast of both 1. & 2....and to make matters more like Scotch mist, the rules and weighting given to either 1. or 2. can be all over the map!

Like maybe no-one gives a damn in the software department, and on a an audit by the Inspector General that part of the brain team claims they are just following orders from down-line. If that sector is sending goofy electrical signals that's what they are going to translate into consciousness. "Hey we just work here, go beat up those efferent nerves down in the cochlea department!"
Down in the IED blasted (or aminoglycoside creamed) auditory hair cells zone, the poor things are actually super-heroes by even attempting to send out any signal at all. Maybe they are even pretty hung up on sending the single last message they got......BAAAANG!!!....Their report to the Inspector General (in soto voce, or voce semi-garbled croaky wheeez) is: "I mean, zzzttt... like, vrrrttt..........do you know...tshhhhhhishhhh.....what it's like to even get....zzrrrrrrrrr....hit by a fu.........bbbbbbzzzzzaaaattt...'ing IED Sir?"
Upon surveying the damage, the IG distributes purple proton medals and wonders if the department should be shut down completely, or wait and see if it can somehow recover a little bit.
Needless to say the IG departs and ponders how to report this co-mingled mess: 'All this is above my pay grade. I just want to retire and watch the next season of "Homeland" c/o the eye department.'
Next stop is the Central Control Room where there's the darn report to file on this mess. Problem is, it's not clear if the software team is just being a lazy bunch of SOB's not putting enough effort into adjusting the signals with their multiple layers of magic, or whether they really can't do much with the input they're getting.
If the latter is the case, then DC (damage control) is going to have to come up with a some as yet to be discovered NRJ (neural resurrection juice) for Cochlea zone, or kick the crap out of software and have them slowly install a patch to at least bring some order to the incoming from Auditory. 'Ha, yeah, I bet software is going to say that if they can do anything at all it's going to take about 6 months to a year. On average. Given their take on the issues involved. The whiners...they are going to claim that 'Consciousness' is a real bear to work with or manage to adjust'...Hmmmmmm.
After wandering for some time, the IG sighs deeply and remembers that the next task is another bear...trying to find where the Central Control Room is now. The thing keeps shifting all over Brain Place without telling anyone in advance!!!...Bigger sigh.
Fade - with IG forlornly looking left, right, up and down.

I expect the T researchers and theorists are not going to be out of a job soon...

Best, Zimichael

 

So I've been thinking @jazz

If I for example have severe damage at 6000 Hz which result in T and lesser damage at 5000 Hz which result in H. Would it be theoratically possible to make the damage at 5000 hz even more severe so it would go from H to T? And thereby eliminating H?

And another thing which might be off topic:
Recently, some dude at a swedish forum reported that he accidently cured his 6 months old T by going to a night club. Would it be possible that he made his severe damage that resluted in T even more severe so it resulted in deafness in that specific frequency he had T? But it's such a deafness one wouldnt really notice. Do you follow my thinking?

 

@lapidus Both excellent questions! But I can't answer them. Of course, the researchers' ideas about tinnitus and hyperacusis are still only theories. It will be interesting to follow their work as they continue to explore their ideas.

And I like the idea that tinnitus and hyperacusis are similar conditions. If true, it is likely that tinnitus drugs will also work on hyperacusis.

 

This is interesting, I've also read a couple other accounts of people getting rid of their tinnitus through acoustic trauma, it's not something I'd be willing to try but it's pretty interesting to think about it.

 

I wonder if you got blasted for a split seconded with the frequency your t is that your brain or ears would stop ringing?

 

Not a test I would be willing to take. lol

 

I can translate his whole statement to you guys:

"Hear and behold!

I've been having T for about 6 months until this Sunday. It has disappeared and not come back. I can't understand how this could've happened beacuse I put my hearing at risk the whole weekend. I was at a party, then a night club all night, something I usually don't do. I was very bothered by the loud music in the club, it was extremely loud and you couldnt hear anyone talking. I was convinced it would make my T even worse but when I woke up the next morning there was no sign of T. I've been having non stop ringing for 6 months and it just disappeared after a night's partying. Isnt that weird? I don't recommend anyone else to try the same thing though. Always protect your ears."

Antoher Guy on that forum who seems quite knowledgeable explained the phenomenon by saying that T is when the brain is in a shock state and it has now reveresed by adding another shock. I don't really buy that explanation, but it seems to be more than a coincidendce that this guy's T disappeared the same night he goes clubbing.

 

Interesting. I was thinking somewhat in the same lines. That if you could make out what exact frequency you have T in, you could blast yourself with that exact frequency . Wouldnt work for me though since I got a whole orchestra in my head.

 

I may be off but isn't this just Resiual inhibition?

 

Jazz, have just been reading more and more since my post. Realize that many etiologies, even if not inner ear derived, can produce glutamate re neurons overfiring which will adversely effect the auditory system. So I am beginning to understand the fact that most t etiologies may be connected to hearing loss, even if shown as normal hearing on audigorams/OAEs.

 

Yes and remember audiograms don't show all the damage that might've occurred in your cochlea--damage that might not show up as hearing loss.

You might be interested in reading this short article about hidden hearing loss and tinnitus:

http://www.tinnitusresearch.org/en/...usResearchArticleSeries_forTRI_4_Schaette.pdf
​

Here is an excerpt from it:

 

Thanks, @jazz
Interesting stuff.
Still not clear to me if normal OAEs shed any light on this study.
Also, I wonder if "hidden hearing loss" in this study can show the nerve (or areas around the nerve) effected at the brain stem/central auditory cortex level rather than inside the cochlea/inner ear cells level. This still seems unclear.
I have normal OAEs and normal audiograms. My t was triggered by local anesthetic at the same time as menstrual migraine. A leading t researcher/doctor in the US says that my t was not caused by inner ear damage, and is more of a central auditory response. However, that still does not rule out the "hidden hearing loss" or at least reduced thresholds at different levels of the auditory system.
I have been reading that when other etiologies of t are produced, besides due to noise exposure, i.e. head injury, drugs, stress etc, excess glutamate is released which could potentially cause this hidden hearing change along the system.
I understand that inner hair cells are the main areas of hearing loss, but I guess it can extend along into the brain as missing interpretation of sound etc. There's a fine line between the two, especially as the nerve travels from the cochlea to central brain.
Not sure if this makes sense?

 

Shouldn't this mean that everyone should have 2 tinnitus frequencies? Well in my case this might be true because I have on frequency at 14300Hz (more in right ear) and another around 9300Hz (more in left ear). But the weird thing is that I can hear pretty well between those frequencies. After 15000Hz my right ear seems to weaken a bit more. No hearing loss at normal audiogram range. I think I can hear up to 17000Hz at low/moderate sound levels but hard to tell. Most headphones have big drops in frequency response after ~14500Hz so can't really test it myself

Could it be the case that if enough hair cells, synapses or neurons are disconnected from the brain - the T is produced even tho you can still hear the frequency in question with the remaining connections?