The tinnitus I hear – all the time

I just came across some sound-samples that simulate my own tinnitus. I wanted to share them, so perhaps people around me better understand why I am tired or unable to participate in social activities.

  1. This is similar to the "quiet" tinnitus that I have all the time 24/7 
    (I can barely hear this sounds when I listen to it, so I guess it’s pretty close to my own)
  2. Also barely audible to me, meaning it’s similar to my own
  3. Whistling sound
  4. This one is totally inaudible to me, meaning that I have this as tinnitus for sure…
  5. Screeching
  6. I also have “white noise” kind of tinnitus, but all the examples I have found are too high i frequency, so “white noise” with deeper frequency is another example (you just hafve to imagine the sound)
  7. All these above combined, and you might have a sense of the cacophony that is in my head at all times…

tinnitus

The only time I don’t have tinnitus, is when I am so preoccupied with something else that I “forget” it, or when I sleep.

Tinnitus get’s worse (more loud and more “present”, harder to ignore) when I have slept bad, or when I am getting more tired or sick like with a flu.

Why do I have tinnitus, even with CI’s?

I have been thinking back, trying to get a clue as to the reason why my CI-operations didn’t “solve” or remedy the tinnitus problem, and have worked out this theory:

from bad comes goodFrom around 2000 and onward, I cranked up the sound volume on my hearing aids every time I had a control or new hearing aid or simply needed adjustments. The result of this cranking up? I walked around with an aproximate loudness of 100 dB to 120 dB and more for 10 years! This might have resulted in the development of recruitment (norsk), hyperacusis (norsk), even more hearingloss (aka more rapidly deterioriating hearing) and tinnitus.

Furthermore my theory is that all these years of unusual loud sounds coming from my hearing aid, resulted in my brain (the parts receiving and processing the electric nerveimpulses of sound) underwent some structural change or that my sensorineural system developed some kind of damage. I am not a neurologist or expert in any medical field, so these are a laymans theories…

I feel that the health services in my country failed in providing adequate help to me in a reasonable time-frame. Maybe I could have been without the tinnitus, had I been helped 5 years earlier… I’m not bitter, I just want others to learn from what happend to me. And to prevent others to have to deal with the same things, if it’s avoidable…

Going deaf – twice

beethoven-777x934In many ways, the process I have been in after the second operation has been about accepting that I am nowin fact deaf. Yes, I can hear with the CI, but I can’t use them (to hear) all day. In fact, two – three hours per day is my present maximum dose of sound. I have to learn to live a large part of my life as a deaf person. Also it’s not just me, but my family has to learn to have a deaf person around them too.

Learning sign-language at Ål – School for deaf

pMy wife has identified the need for us all to learn sign-language. I have been too stubborn to realize it or initiate it. At the same time I have always been open to it, thinking that refuting something that might actually help, just because I don’t want to be deaf, is a counterproductive thing to do. So I am open to it, and we actually went to our first week of school, for the whole family, to learn sign language just a few weeks ago.

It was an eyeopening experience, and we will learn to sign in our family.

The difference between “recruitment” and tinnitus

I just want to be very clear on the difference between these two phenomena.

They’re both auditory sensory related, but have some significant differences.

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What happened with the “recruitment”?

I got this question from a reader (Candy):

Kim’s post send me here, and I really like your post.  What gets me amazed is that I do have that problem some of the time and I never knew there was a word for it!  😉
Do you have implants now? and, if so, does it helps get rid of recruitment?  If it does, then it would be a good reason for me to get it and stop procrastinating!  😉

Instead of answering Candy directly, I think everybody who has read my original post about the phenomenon called “recruitment”, also deserves to see my response:

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Unrealistic Expectations from the World? Audism?

What do people expect from me? They expect me to participate in social activities and to be part of the “common consciousness”. That is a fair expectation in my opinion. In this blog post I want to take a look at some circumstances and  obstacles concerning these expectations. I think it will be wise to read the definition of some of the words I use, they are Prayer-no-expectationlinked, as the word “expectation” was just linked.. That way we will be on the “same page”.

In this aspect I am thinking about what we expect and when we expect it in terms of my hearing progress. This is also a sore and difficult point on my behalf, since it is much about social interaction and how I am perceived socially. How I am viewed as a person.

As I’m going the path of CI rehabilitation and re-learning to hear, I am doing some discoveries about expectations of my recovery from both myself and others near and dear.

Me, a social outsider

All my life I’ve been a part of the hearing world, and thus a social outsider. Even among my closest friends and family, I got and still get, remarks and comments that hurt to the core of my being. I’m sometimes left with a feeling that people suspect me of WANTING to be isolated or withdrawn from issues that are talked about. I often feel misunderstood and misinterpreted. For instance my withdrawal from social events is sometimes being interpreted as a lack of interest, or attempt to socialize. That is so unfair and sad. I’ll explain why…

The more people talking at the same time, the more impossible it is for me to interact in a meaningful way. Believe me when I say I really wish I was able to interact with others on their terms, but there is a huge damage in my hearing that makes that incredibly hard. There is a limit to everyone’s mental capacity and endurance. My limit is shorter than most in terms of social interaction due to the nature of listening and understanding.

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Bad “hear” days and other things

Happy New year everyone!

frustration3 I am a bit frustrated these days, and that frustration has several sources. I feel a bit stagnated and stuck, I can’t track any sound improvement. On the contrary I feel like sliding backwards every time I’m a bit tired. It is like this: when I’m tired, my brain has less energy, less stamina, and the automatic sound processing deteriorates noticeably. I’m having some of those bad “hear” days, these days.

Other reasons for frustration are personal reasons due to me looking forward to move together with my girlfriend, but have to wait for other parties (paper mill stuff) in order to realize it. And the last prime reason for my frustration is that it is absolutely freezing these days (below –4 F / 20 C), and I can’t find all my winters garments as I’m living at two locations simultaneously and both are a mess at the time.

Alway look on the bright side of life!

But on the bright side of life (as Monthy Python likes to sing about :-)  ), chaos and challenges is almost always a good thing. A new order rises from it, bringing new perspectives and a feeling of a fresh start.

I’m not constantly working as hard as I used to, in order to understand speech. (I think I manage that part about not working too hard quite well these days, partly due to the seasonal darkness and feeling of powerlessness.) I’m focused on resting up…

A big life altering decision – a new career

One big important thing that I recently decided upon, was that I’m going to pursue a new career. I’m going to put the IT-career on the sideline, keeping it as a bi-income via my own company, and as a hobby. The IT-knowledge will be useful to me no matter what.

This new career involves me first going back to school for 3 or more years. That fills me with both anticipation and fear. Looking forward to new input, knowledge, making new acquaintances, experiences and fearing the situations where I can’t cope in terms of lectures, meetings etc. Will it, as before, be too much for me to overcome?

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Rewiring my brain – altering the language system?

brainscan

How a person understand and interpret speech is an extremely complex process involving the synaptic responses to the physics of sound, neural activity in the nervous system and brain, and ultimately the processing of those neural impulses in various regions of our brain.

Scientists have started mapping those regions of our brains by watching what happens inside the brain through MRI, PET or other means of scanning technology. Also, people who have had damage to their brains have helped us gaining more understanding about which parts of our brains does what.

Speech and language, meaning the vocal transfer of meanings, feelings, ideas, ideologies, experiences and everything else human beings exchange and communicate, are processed through various parts of our brain.

Some of the components of speech and language processing in our brains are about (I’m sure there are many, many more, each specializing in it’s own incredible way!)
1. acoustic processing
2. visual processing for lip reading
3. phonology
4. semantic processing (vocabulary)
5. short- and long term memory (previous context, experience, reference)
6. visuoauditory, meaning that the brain both processes and somehow merges each individual sensory input (bisensory – vision and hearing); keep in mind, we don’t fully understand everything about our brains functions yet.
7. contextual processing
8. “alternative contextual qualified guessing” (you might also call it fantasy 🙂  ) when all other understanding strategies fails, it’s the last attempt of understanding, and results in either a question, embarrassment or success

OK, that was the crash course in what we know about how our brains processes speech in a oversimplified manner.

Taking that info into account, think about what happens if the signals changes radically? What happens when a hearing-aid user, de facto deaf (unable to comprehend speech without the sensory aid of hearing aids, or contextual aid of sign language, lip reading or written text), is fitted with a CI or two?

In my case: what happens when I have suffered from “recruitment” while using my hearing aids for many years, and then suddenly both the recruitment is gone, AND the perceived frequencies have shifted totally out of it’s previously normal neural pathways starting with the hair cells in my cochlea.

My implant feeds electronic impulses to the part of my cochlea array of left-for-dead, broken hair-cells, while the previously still somewhat functional part now is left abandoned, not receiving any kind of stimuli anymore. (it’s like playing a piano on the octaves situated on the far left side for your whole life, and suddenly someone moves the entire piano so that you now sit on the far right!)

MEart1Well, obviously my brain has some work to do! The rewiring of the neural pathways are one thing, and the brains processing are another. I believe we can agree that the neural rewiring both in our nervous system, and in our brains (which I agree, is in fact part of our nervous system) is about new synaptic paths forming, adjusting our nervous system to the new sensory reality.

But what about the brains’ processing of these sensory inputs? The part of my brain that performs acoustic processing adjusts to the change in frequencies, the new auditory virtual reality slowly becomes THE reality, due to the lack of, and loss of the old auditory reality.

The phonology of all words have changed, how does my brain cope with that? Rewiring, relearning.

The short-term memory function now has to deal with input data that are totally new in appearance. It doesn’t sound like before. A streetcar doesn’t sound like a streetcar. A woman in high heels sound like a carpenter hammering down a nail. A kid laughing sounds like an animal dying. A kid crying sadly sounds like a anger fit.

Do you see where I’m getting at? The change in the quality of the sound perceived, also changes the contextual package, ie. what my brain interpret that specific sound to be, also decides my initial contextual and sometimes emotional processing. So now my contextual database also has to be reprogrammed.

The long term memory databank contains data that are now invalid. My mothers voice doesn’t match her voiceprint in my brain. All the people I have learned to identify by their speech patterns (how they pause, how they etc) now needs to be reprogrammed. It’s like having to change your entire music collection of vinyl to low quality compressed digital music (like computerized music in the MP3 format).

Borg I will forget the old information, and fill it up with the new. All as the “Borgs” in Star Trek says: “You will be assimilated.”

If the part of my brain that does the acoustic processing changes it’s algorithms, I assume it’s fair to expect a change in the output from that process, consequently leading to the fact that the part of my brain that is the recipient of of the processed audio, now being “re-digitalized”, also have to change THEIR algorithms!

In that way, my entire language system is presently under a complete and heavy and thorough modification.

I have noticed this in the following ways:

I can “hear” better, but I have problems remembering the first part of the sentence that I hear, OR I only perceive the first part, my brain skips the last part of a sentence. I deduct from this “brain rewiring hypothesis”, that my short-term memory is having trouble storing the strange sounding words in it’s flash memory. The input data kind of doesn’t fit properly.

The other parts of my language system also sometimes suffer from overload or fault, causing a crash. Like when ambient noise occurs, and the voice I listen to drowns in that noise, my contextual and visual processing brain part needs to take over, but since I have been so focused on the auditory processing (due to the new and strange sounding quality), the take-over comes just a little bit too slow to be able to follow the person talking…

Think of this last paragraph like trying to follow an intricate discussion about a complex issue while having two or three kids climbing all over you, demanding attention. Sometimes they DO get your attention, and what happens then with the discussion you were following?

That’s when my “alternative contextual qualified guessing” kicks into gear 🙂

And this time I won’t even get into the emotional and psychological aspect of this brain-rewiring process that I’m currently undergoing… 🙂  I think each and every one of you who reads this can imagine the psychological and emotional implications for yourself.

Some things are best left unsaid?

CI-activation log no. 4 – day 5 – Initial shakedown

Wow, what a week! I’m very tired now, but need to put some impressions onto writing…

Have already had many CI-moments, here are the ones I remember now:

  • the dogs at my mom; when they walk on the hardwood floor they give off a ticking sound for every step. I can detect them moving with sound only!
  • I can detect the chorus in rock songs that I know well; like “Girls, girls, girls” by Mötley Crüe (I also hear the motorcycle revving in the beginning!)
  • I detect my son singing in the car while the window is open
  • Jingling of my key-chain
  • I hear mobile phones ringing in TV-shows (never heard that before, ever!)
  • I could detect my sons heavy breathing in the car (he had just been running, racing me to see how far he can get from the garage before I catch up with him, I have to wait for the gate to open first)
  • I detect the difference between –s and –sh

I10-85-cochlea2 All sounds are very thin, high pitchy. That is due to the fact that my hearing residue before the operation all were located in the innermost curves of my cochlea. (from 1500 Hz to 200 Hz in the diagram on the left) That’s where the bass is. The entire frequency range that my hearing aids could amplify, and the vibrations the hair cells were able to pick up, were dealt with by the hair cells in that that innermost curve. (Because of the limited number of remaining hair cells in the outermost areas, I experienced recruitment.)
Now, all those frequencies go to the previously almost dead outer areas of my cochlea (20 000 Hz to 1500 Hz). Which used to be the medium and high pitch range of sound vibrations were picked up by hair cells. Because of this radical relocation of sound information in my cochlea, my brain has to rewire all the frequencies through neurons forming new permanent pathways to the old brain-recipients cells who did the actual “hearing”. Until that rewiring has completed, it will continue to sound high pitched and heliumish.

I wonder if the brain would be able to do the job by itself without the aid of any other senses? Now I’m telling my brain what sounds should go in there when I drive the car, or listen to that rock music, or hear my sons voice. Because I SEE the sounds. But what if I did not see anything, just had to figure out the sounds? I’m thinking my brain probably works both ways, some sounds it’s rewiring by itself, some are helped by my thoughts… Anyone with insight into how this process might work?

As I stated in the beginning, I’m really tired! Today I had a 4 – 5 hour period where I did nothing active… (very unusual for me) Last night my son snuck into my bed behind my back without me noticing it before it was too late (he had fallen asleep). That’s never happened before. Usually I have a very sharp sense of sight, detecting any movement very fast.

All kids are really great about my CI. They fancy the magnet and think it’s way cool 🙂

The first 3 days of my CI-life, I suspect I was high on adrenaline. Everything seemed more crisp and sharp. Now I’m almost like I was before I got activated. Dead tired, numb in my bran (just not as “muddy”) and with some psychological reactions, especially very sensitive to any stress, which gives me this tremendous tinnitus again, only now it’s in both ears, and it’s has changed quality in my implanted ear… more low frequency than before, or it’s just my brain who has already started rewiring? Where does the tinnitus come from? Auditory hair cells in cochlea who are trapped in an eternal death scream, or is it from my brain which screams for those frequencies, and when it gets nothing it creates it by it’s own?

I have been avoiding the issue of tinnitus, partly because it’s has been my strategy, to ignore it away and to death, and that has worked quite well… If the tinnitus thing continues now after the CI-implant, I will have to read up on the issue… And I’m afraid the tinnitus on my left ear will take over the job since my right ear now gets plentiful of audio information….

I listen to TV-shows and movies with both the CI and the hearing aid most of the time, sometimes I turn off my hearing aid for a while. While I drive the car I only use CI, since I get too much recruitment from the hearing aid ear. While I’m walking around in shops, ore doing daily chores, I use only CI.

I need the hearing aid to communicate to everybody.

Patience, understanding and love

When I started this blog in late 2006, I had a feeling it would be a long journey (that’s why I started the blog in the first place). That suspicion became stronger after receiving a letter from the hospital saying that they had an obligation to operate on me before 2010. What I had ahead of me back then, has been more or less as expected. I was prepared for a long haul.

“To exist is to change, to change is to mature, to mature is to go on creating oneself endlessly”. ~Henri Bergson

I want changeMy every day life has changed a lot. More activity, never a dull moment. I wish the day had more hours :-)  I’m not “waiting” for the CI anymore, I let that struggle go this winter, focusing more on my own life and people around me. (Mind you, I still need the CI desperately!) I’ve had enough of trying to understand why Rikshospitalet are not able to operate more than 50% of what the Health ministered ordered last year (see some of my previous posts). I don’t think my engagement into this issue has any meaning or bearing anymore. I’m sad to say this. (I hope I had a little impact, but I have achieved no real results, to my knowledge anyway.)

Waiting, waiting and more waiting. In fact, it has been so much waiting, that life happened during the waiting 🙂

And life is what everything is about, isn’t it?

In retrospect I can with great certainty conclude that I did all the right things back in 2006 and 2007. (You have to read the past posts on this blog in order to know what has happened to me and what I have done  :-)  )

I have managed to get my life back. I am in a place that is brighter and better, even though it has it’s challenges. I am where I want and need to be.

I am able to cope with life, and take care of my loved ones and myself (somewhat).

But I’m walking a fine line. Experiences from every day life tells me that I have very little to go on. Only thanks to the slow process of acknowledging that I’m by definition deaf, I have come to understand better what the process of loosing one’s hearing does both mentally, physically and socially. And take some precautions in order to preserve myself from exhaustion.

I am deaf, I use hearing aids to take advantage of the very little hearing residue I have left and thus suffer from a rather severe case of “recruitment”. I have tinnitus on both ears, get tired really quickly in general (and then the tinnitus really howls!) and have no chance of keeping a regular job. I need all my strength to take care of my son, my dearest girlfriend and her son, and last but not least, myself.The Fight Of My Life IMG_1252

I had to fight to get my life back. I had to fight with my willpower in order to do all the right things in many areas of my life. I changed a lot in my life. I changed myself in many ways. I changed how my family perceived me. I had to get them to understand me better. And it helped.

In a way I had to try NOT to fight, too! By accepting my fate and my condition (it is by no means a surrender, mind you! :-)  ) I have learned that my mind and willpower can work against me as well. Rather than standing tall in the strong wind, risking to break something or get hit by flying debris, it is better to bend over and lie down on the ground and survive. Sometimes it is much better to accept fate and accept conditions, rather than opposing the facts and use a lot of energy trying to get things my way. The consciousness of this “bend before you break” is helping me in many areas of my life.

This blog will remain active at least until I have received my first CI by the end of this year, but it will be less active due to lack of time and energy to keep it updated.

I have learned to suck things up. Take a punch. Even though life is hard when it comes to my health right now, I have so much to be grateful for. I will not allow myself to turn sour or negative. What happens happens. I’ll do my best and want to keep a positive mind about everything. All is good until proven otherwise 😉

I’m going to use this experience to improve my own life in the future. No matter what. There is another day tomorrow!

“If we don’t change, we don’t grow. If we don’t grow, we are not really living.” ~Gail Sheehy

Unconditional condition

I just sat very comfortably in my favorite chair in front of my computer for two hours, doing some work that requires concentration. I had no sounds to distract me, since I turned my hearing aids off for the work-session.
I can’t stand the sound of the fans, even though I have water-cooled most of my rig, the hard-drives give off too much heat for the whole thing to be able to run without fans… I think the sound can’t be much more than 17 – 20 dB (according to fan specifications), and that’s a faint sound, really. But my hearing aids are the most powerful there is (to my knowledge) and they’re cranked to the max. (Widex Senso Diva). So I turn them off more and more these days…

The recruitment is killing me if I don’t turn them off.

The tinnitus is there as always, but not really bothering me concentration-vise. It’s sort of comforting, since the sound now has a rather steady tone. (before it was a chaos of frequencies and variations in strength/volume)
Anyway, I sit, my head is not moving, my eyes are only fixated on the screen, and my concentration goes to the task at hand. The first hour goes fine, no problems.
The second hour I start to get physical sensations in my head. It is like pressure building slowly up.
I had a good night and I’m not tired. I have no stress to complete the work I do, and have no deadlines for anything. It’s Sunday 🙂

radThen suddenly I get these auditory sensations, it’s like a silent storm. I can feel it somehow. Not like pain, it is not unpleasant, it’s just a sensation of very weak electric current in my brain. Like a blanket of electricity sliding back and forth like the radar screen image.  It’s like a soft “wooosh” inside my brain…
The sensation that I have are connected to my ears, and at the same time they affect all of my brain (at least it feels like it does). I have no control of this sensation.

I wrote about this sensation before, connected to a pre-sleep phenomenon. This is very much the same, only now I get it during daytime too…

Seconds after this “wooosh”-sensation I feel dizzy (I guess there’s some kind of activity affecting my Vestibule where the balance-nerves are situated). It’s a weak vertigo, even though I sit still, are at peace with no stress. And I know I don’t have Meniére, thank goodness…

After this my ability to concentrate is worse. It’s difficult to keep a thought for as long as I like. My mind has always been a multitasking one; while doing one thing, my mind has been working out what the next thing I should/want to do… This is impossible in the state I’m in after only two hours of working effortlessly… It’s frustrating for me, because if I’m doing something that gives me a thought that I want to pursue, the short-term memory isn’t working as I’m used to. So when I complete the task I worked on, I KNOW that there was something I thought of doing, like searching for a special kind of information, or look up a certain fact etc. etc. But it’s gone… Sometimes I sit for 10 minutes of more, pondering what it was that ignited that thought, trying to reconstruct the idea for myself… Sometimes I get it, most often I just move on… I can’t let it get to me.

In short it makes me feel like I’m cognitively amputated… The SUDOKU-thing helped me understand this better…

And by writing this now, and concentrating on the subject and all the aspects of writing, I feel I’m pushing myself… I’m starting to get a headache now… This is the part I do not understand at all…

I haven’t heard a sound all morning (it’s now 12.30, I started working at 9.30). I know my hearing is disappearing, and the tinnitus is singing it’s tune. But why is it a strain for me to do something that doesn’t affect my hearing? Why do I get this dizzy feel, why the headache, why the memory-problems, why the multitasking problem, why the feeling of fatigue? Can it be that the optical-nerve also lies close the the nerves of the auditory nerve and the balance-nerve? It is all connected somehow…

My jaws feel like they had a punch (they’re sore, like I chewed gum for a few hours). My temples hurt a little bit. The dizzy feeling is there (but I’m not having trouble with the balance, though).

This state/condition will last all day, until late at night, then I feel better again, but the paradox then is that I need to sleep. I might me tired, but want to stay up because the world feel somewhat more vivid to me. Is it connected to me originally being a B-person? I’m not extreme, have no troubles getting up in the morning whenever… (but used to)

Vestibular disorder symptoms I have experienced

I came across an interesting website for an organization called VEDA (VEstibular Disorder Association).  I found this list of possible symptoms that is very interesting.

Image copied from “vestibular system.” Online Art. Encyclopædia Britannica Online. 23 Jan. 2008
Here is an explanation of the Vestibular system.

I did not initially place all these symptoms into the same category (i.e. having to do with my hearing), but maybe I should have??? I exctracted the whole list and will excempt (a strikethrough line) those not experienced by me. If commented, the comment has been marked like this.

This list was a revelation to me… It all fits, kind of… Seems it connects to the wiring of the vestibulo-cochlear nerve: the nerve that carries information from the inner ear to the brain. Also called the eighth cranial nerve, auditory nerve, or acoustic nerve. If the “recruitment”-theory in my previous article holds water, the information about these symptoms could also have some bearing on the subject of my condition.

Vision

  • Trouble focusing or tracking objects with the eyes; objects or words on a page seem to jump, bounce, float, or blur or may appear doubled
  • Discomfort from busy visual environments such as traffic, crowds, stores, and patterns.
  • Sensitivity to light, glare, and moving or flickering lights; fluorescent lights may be especially troublesome Very much so!
  • Tendency to focus on nearby objects; increased discomfort when focusing at a distance
  • Increased night blindness; difficulty walking in the dark Yes, have to find walls or points of support in order to be able to move, get a complete feeling of immediate disorientation
  • Poor depth perception

Hearing

  • Hearing loss; distorted or fluctuating hearing Well, that’s not exactly news…
  • Tinnitus (ringing, roaring, buzzing, whooshing, or other noises in the ear) Very much so!
  • Sensitivity to loud noises or environments Especially high pitch like childrens voices
  • Sudden loud sounds may increase symptoms of vertigo, dizziness, or imbalance Yes!

 

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Explaining the analogy: "Recruitment" of hair cells in cochlea

During my research into my own declining hearing- and health condition, I came across information about a phenomenon regarding hair cells in cochlea called “recruitment”. I strongly suspect “recruitment” is what happens to me. It certainly would explain a lot of the things that happen(ed) to me and my hearing and the fatigue…

(Most of the text that follows is copied from this page at hearinglosshelp.com and edited by myself for the sake of this blog and my readers.)

What is “Recruitment”?

Very simply, “recruitment” is when we perceive sounds as getting too loud too fast. How is it possible to hear too loud when the hearing in fact is vanishing, you may ask… Well, be patient with me and read on…

“Recruitment” is always a by-product of a sensorineural hearing loss. If you do not have a sensorineural hearing loss, you cannot have “recruitment”. In simple layterm this means that this condition only affects those who have a significant loss of hearing caused by haircell-damage in cochlea (mainly).

As a sidenote; there are two other phenomena that often get confused with “recruitment”. These are hyperacusis (super-sensitivity to normal sounds) and phonophobia (fear of normal sounds resulting in super-sensitivity to them). Both hyperacusis and phonophobia can occur whether you have normal hearing or are hard of hearing.

An analogy for understanding how “Recruitment” got its name

Perhaps the easiest way to understand “recruitment” is to make an analogy between the keys on a piano and the hair cells in a cochlea.

The piano keyboard contains a number of white keys while our inner ears contain thousands of “hair cells.” Think of each hair cell as being analogous to a white key on the piano.

The piano keyboard is divided into several octaves. Each octave contains 8 white keys. Similarly, the hair cells in our inner ears are thought to be divided into a number of “critical bands” with each critical band having a given number of hair cells. Each critical band is thus analogous to an octave on the piano.

Just as every key on the piano belongs to one octave or another, so also, each hair cell belongs to a critical band.

The requirements for “Recruitment” 

When you play a chord on the piano—you press two or more keys together but they send one sound signal to your brain. Similarly, when any hair cell in a given critical band is stimulated, that entire critical band sends a signal to our brains which we “hear” as one unit of sound at the frequency that critical band is sensitive to. This is the situation when a person has normal hearing.

However, when we have a sensorineural hearing loss, some of the hair cells die or cease to function. When this happens, each “critical band” no longer has a full complement of hair cells. This would be analogous to a piano with some of the white keys yanked out. The result would be that some octaves wouldn’t have 8 keys any more.

Our brains don’t like this condition at all. They require each critical band to have a full complement of hair cells. Therefore, just as any government agency, when it runs short of personnel, puts on a recruitment drive, so too, our brains do the same thing. But since all the hair cells are already in service, there are no spares to recruit.

Getting to the point – what “Recruitment” means

What our brains do is rather ingenious. They simply recruit some hair cells from adjacent critical bands. (Here is that word: recruit or recruitment.) These hair cells now have to do double duty or worse. They are still members of their original critical band and now are also members of one or more additional critical bands.

With only a relatively few hair cells dead, then adjacent hair cells may just do double duty. However, if many hair cells die any given hair cell may be recruited into several different critical bands, in order to have a full complement of hair cells in each critical band.

 

 

The results of the phenomenon known as “Recruitment” – the conclusion

The results of this “recruitment” gives us two basic problems. (notice the underlined parts!)

  1. The sounds reaching our brains appear to be much louder that normal. This is because the recruited hair cells still function in their original critical bands and also in the adjacent one(s) they have been “recruited” into.

    Remember that when any hair cell in a critical band is stimulated, the whole critical band sends a signal to our brains. So the original critical band sends one unit of sound to our brain, and at the same time, since the same hair cell is now “recruited” to an adjacent critical band, it stimulates that critical band also. Thus, another unit of sound is sent to our brains. Hence, we perceive the sound as twice as loud as normal.

    If our hearing loss is severe, a given hair cell may be “recruited” into several critical bands at the same time. Thus our ears could be sending, for example, eight units of sound to our brains and we now perceive that sound as eight times louder than normal. You can readily see how sounds can get painfully loud very fast! This is when we complain of our “recruitment”.

    In fact, if you have severe “recruitment”, when a sound becomes loud enough for you to hear, it is already too loud for you to stand.

  2. The second result of “recruitment” is “fuzzy” hearing. Since each critical band sends one signal at the frequency of that spesific critical band, when hair cells get recruited into adjacent bands, they stimulate each critical band they are a member of to send their signals also. Consequently, instead of hearing just one frequency for a given syllable of sound, for example, perhaps our brains now receive eight signals at the same time—each one at a different frequency.

    The result is that we now often cannot distinguish similar sounding words from each other. They all sound about the same to us. We are not sure if the person said the word “run” or was it “dumb,” or “thumb,” or “done,” or “sun,” or? In other words, we have problems with discrimination as well as with volume. If our “recruitment” is bad, our discrimination scores likely will go way down.

    When this happens, basically all we hear is either silence, often mixed with tinnitus or loud noise with little intelligence in it. Speech, when it is loud enough for us to even hear it, becomes just so much meaningless noise.

    This is why many people with severe recruitment cannot successfully wear hearing aids. Their hearing aids make all sounds too loud—so that they hurt. Also, hearing aids cannot correct the results of our poor discrimination. We still “hear” meaningless gibberish.

    However, people with lesser recruitment problems will find much help from properly adjusted hearing aids. Most modern hearing aids have some sort of “compression” circuits in them. When the compression is adjusted properly for our ears, these hearing aids can do a remarkable job of compensating for our recruitment problems.