Tinnitus Is Associated with Reduced Sound Level Tolerance in Adolescents with Normal Audiograms...

Tinnitus is associated with reduced sound level tolerance in adolescents with normal audiograms and otoacoustic emissions

Abstract

Recent neuroscience research suggests that tinnitus may reflect synaptic loss in the cochlea that does not express in the audiogram but leads to neural changes in auditory pathways that reduce sound level tolerance (SLT). Adolescents (N = 170) completed a questionnaire addressing their prior experience with tinnitus, potentially risky listening habits, and sensitivity to ordinary sounds, followed by psychoacoustic measurements in a sound booth. Among all adolescents 54.7% reported by questionnaire that they had previously experienced tinnitus, while 28.8% heard tinnitus in the booth. Psychoacoustic properties of tinnitus measured in the sound booth corresponded with those of chronic adult tinnitus sufferers. Neither hearing thresholds (≤15 dB HL to 16 kHz) nor otoacoustic emissions discriminated between adolescents reporting or not reporting tinnitus in the sound booth, but loudness discomfort levels (a psychoacoustic measure of SLT) did so, averaging 11.3 dB lower in adolescents experiencing tinnitus in the acoustic chamber. Although risky listening habits were near universal, the teenagers experiencing tinnitus and reduced SLT tended to be more protective of their hearing. Tinnitus and reduced SLT could be early indications of a vulnerability to hidden synaptic injury that is prevalent among adolescents and expressed following exposure to high level environmental sounds.

Link to paper: http://www.nature.com/articles/srep27109

 

This does not surprise me at all!
By now researchers must know that the audiogram, that is still universally used to asses hearing damage, is just hopelessly antiquated.
A good thing that researchers are devising more accurate methods to determine what is damaged in and around the inner ear.
Unfortunately at the moment it is still accepted (often opportunistically) that if your audiogram is within normal levels, you do not have a problem in the inner ear. Frustrating when you are in a liability dispute.

 

YES! I wish I could super-like this post!

 

This research strengthens Dr. Richard Salvi's theory that everyone with T also got H, but most have it in such a mild form that they aren't aware of it (unless they do an LDL test).

 

I've had T since 18 (from elecontric festival w/ no plugs and had temporary threshold shift there) with perfect hearing. Last year in June I got awoken to a woodsaw outside my window, perhaps 10 feet. I believe me sleeping made me more so susceptible to the noise. I instantly awoke and put my hands over my ears in fear. It lasted probably 10-15 seconds. Yet, 3 days later I wen't to bed with awful T and deteriorated from that point with louder T fluctuating and H.

My test last year was "that of a 8 year old child". Awesome, right? Without a doubt I've developed a reduction in my tolerance levels to noise. If I can't even handle a 10 seconds of a 110 woodsaw what's going to happen with an emergency veh. hits me?

I believe I have reduced tolerance in some cases and some is from the H though, high pitch things cause discomfort in my ears. Carts going over bumps, or pulling one from another cart making that loud slamming sound. Metal gates, silverware hitting a sink..anything high freq. seems to be really loud and cause discomfort, real noticeable discomfort, so I think that is an H issue. I suffered for many months with shutting car doors which peaked into low 90's and that bothered me as I felt it was too loud. Planes going by that sound loud but only register at 75-85 that supposedly shouldn't be ear damaging.

I honestly wonder sometimes if these db level we can supposedly be exposed to are legitimate for damaged ears.

 

These sounds you hear are louder because there are specific auditory nerves that act in a way to reduce the frequencies you hear that are picked up by your hair cells. The "in-going" nerve fibers or efferent nerve fibers of your auditory nerve actually amplify the frequencies into your brain. Logically, you would think that this means noise would be much louder to you like it is now, but these in-going nerve fibers actually give you a higher hearing threshold and actually "hear" these frequencies more clearly and precisely. You could think of these neurons/nerves acting as a compressor to the noise volumes out there.

I believe that you're hearing these noises outside, like a plane flying over or a saw going off next door, so loudly, because you have more "out-going" nerve fibers than "in-going". The same goes for me. My hearing has completely changed after having incidents over time where I developed ringing and had times where it subsided after a few days. But then last summer, I developed a slight ringing that didn't go away. Most importantly, I was not able to listen to music through headphones and play my drums anymore because the sound of the drums were not allowing me to process what I was hearing in my headphones as well. So I had to purchase earmuffs that construction workers use to somewhat block out the noise so I could process what I was hearing in my headphones.

Flash forward to last October, I had two more hearing incidents where I developed even louder ringing after, but once again, the "tinnitus" did not go away. From that point on up to now, my hearing in a sense, degenerated. In present day, I have no sound tolerance anymore. I can "hear" sounds from distances and they sound like they are only a few feet from me. If I try and listen to the radio in the car and the windows are down, I can't process what I'm hearing at all. Just like you, planes are extremely loud to me now.

Any normal sound, is now loud. Not painful in a sense like hyperacusis is spoken about (which I did have for high frequencies back in October/Novemeber after my hearing incidents) but my ability to process sounds that I'm trying to focus on while other noises are going on is at its maximum capacity.

I hope you understand what I'm trying to explain to you. I'll leave you with three links explaining the nerve fiber mechanisms.

(1) http://www.hopkinsmedicine.org/news...y_new_contributor_to_age_related_hearing_loss
(2) http://www.ncbi.nlm.nih.gov/m/pubmed/17115038/
(3) http://hyperacusisfocus.org/innerear/

 

I Think this explains a lot of things!!
finally a research with relevance!

 

I remember always being ultra-sensitive to environmental sounds (as in, a low frustration tolerance for something rattling in the car as I drove, dogs barking in yards non-stop, too much sustained background noise anywhere). It didn't physically hurt my ears but it caused an intense sense of just not feeling relaxed when it was present.

For several, several months before the tinnitus happened, I probably WAS in the early throes of a form of hyperacusis. Certain sounds began to bother me so much that I would tense up and move away from them if I could.

However, I NEVER had any tinnitus till after the acoustic trauma.

 

When I was in my teen years, I used to REALLY hate loud noises (my family is Italian, and every time they would yell I would wince). I was always just a quiet kid, though. I loved the silence, reading books, listening to quiet music, etc. I think I was always like this.

I am still very attentive to environmental sound; I feel like I have "super hearing," like for instance I can easily notice when a plastic bottle shifts a few centimeters in the distance in a parking lot and pinpoint its exact location in a heartbeat.

However, despite my lower sound "detection" threshold, I didn't feel like I had to protect my ears very often, as long as I knew the sound wasn't going to hurt me. I always felt like I was just more "tuned in" to my surroundings than others, which is why I was more bothered/affected by sound.

I mean obviously I hate it when people bang hammers very loudly near me and use power tools, but I think I'm just being smart by avoiding these noises, and I could always use power tools briefly if I needed to, just like anyone else. I guess I just "got over" the discomfort... but I was left with unexplained T, even though my hearing thresholds are within normal range (below 15 dB everywhere, averaging 0-5) up to 17-18 kHz.

I don't know why I would have this "vulnerability" to sound though, no one in my family going back generation after generation had hearing problems of any kind, and many of us are construction workers, mechanics, etc. so I don't think this phenomena is genetic.

My own father, who is now a super bright introverted computer programmer with a personality profile exactly like me (INTP, anxious, Type-A) worked 8 hour shifts in loud warehouses, as a construction worker, was very depressed and anxious in his teen years/20s, and had severe allergies for which he was given shots (ALSO like me) went to over 50 rock and metal concerts (*FRONT ROW*) AND has an autoimmune disorder that could increase his vulnerability to noise, ALSO takes MANY medications that can damage hearing. He STILL works regularly with power tools, and never protects his hearing. He's 43 and has NO hearing damage and only very minimal tinnitus not detectable unless in total silence, so I don't think this susceptibility to damage is affected by personality either. Suck on that, psychologists who tell us tinnitus is "worsened by anxiety."

Seriously, minus all the noise exposure, the anxiety, and autoimmune issues, I'm a carbon copy of my dad.

Meanwhile I have screamin' T even though I'm a total nerdy homebody with no noise exposure, and he's fine. W H Y.