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?

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Research Supporting Bilateral Cochlear Implantation

Someone heard me! 🙂

And I got hold of what I needed! A 5 pages long list of research that supports the notion that everybody who needs it should have bilateral CI!

I got in contact with Amy Brown from the Let Them Hear Foundation Advocacy program. She provided me with a huge list called “Research Supporting Bilateral Cochlear Implantation“. It is updated and very much valid for the ongoing battle we have these days in Norway for allowing adults get their CI number two on an as needed basis.

Amy wrote me the following, which I happily honor, given the fact that she gave me the precious list in the first place 🙂
Thanks to Amy and Sheri Byrne from the Let Them Hear Foundation.

Hi Ulf,
Thank you for your question.  This is a proprietary LTHF Advocacy Program work document.  We use it specifically to support our appeals.  I am happy to share it with individuals such as yourself as needed, but it is not intended for public consumption.  We continually update and revise this list to include the latest most compelling peer reviewed medical literature.  It is meant always to be a work in transition. If you know of anyone who needs access to this information, you are welcome to share my contact information with them.  I will follow-up immediately.

Amy Henderson Brown, J.D.
Director
Let Them Hear Foundation Advocacy Program
149 Commonwealth Drive
Suite 1014
Menlo Park, CA 94025

If anyone need this information, I’d be happy to provide her e-mail address. All you have to do is ask. I won’t publish it here because that could lead to her getting more e-mail spam. Better to keep it personal.

Bilateral CI research findings

I will post my findings on the issue of bilateral CI on my blog. Hopefully it helps someone else too…

I want to collect the data concerning this debate, in order to get an oversight of what the medical community discover, as well as what they are writing and thinking about this issue.

Papers found in PubMed:

Patients fitted with one (CI) versus two (CI+CI) cochlear implants, and those fitted with one implant who retain a hearing aid in the non-implanted ear (CI+HA), were compared using the speech, spatial, and qualities of hearing scale (SSQ) (Gatehouse & Noble, 2004). The CI+CI profile yielded significantly higher ability ratings than the CI profile in the spatial hearing domain, and on most aspects of other qualities of hearing (segregation, naturalness, and listening effort). A subset of patients completed the SSQ prior to implantation, and the CI+CI profile showed consistently greater improvement than the CI profile across all domains. Patients in the CI+HA group self-rated no differently from the CI group, post-implant. Measured speech perception and localization performance showed some parallels with the self-rating outcomes. Overall, a unilateral CI provided significant benefit across most hearing functions reflected in the SSQ. Bilateral implantation offered further benefit across a substantial range of those functions.
(Link to more information about this paper)

Speech perception tests were performed preoperatively before the second implantation and at 3 months postoperatively. RESULTS: Results revealed significant improvement in the second implanted ear and in the bilateral condition, despite time between implantations or length of deafness; however, age of first-side implantation was a contributing factor to second ear outcome in the pediatric population. CONCLUSION: Sequential bilateral implantation leads to significantly better speech understanding. On average, patients improved, despite length of deafness, time between implants, or age at implantation.
(Link to more information about this paper)

The average group results in this study showed significantly greater benefit on words and sentences in quiet and localization for listeners using two cochlear implants over those using only one cochlear implant. One explanation of this result might be that the same information from both sides are combined, which results in a better representation of the stimulus. A second explanation might be that CICI allow for the transfer of different neural information from two damaged peripheral auditory systems leading to different patterns of information summating centrally resulting in enhanced speech perception. A future study using similar methodology to the current one will have to be conducted to determine if listeners with two cochlear implants are able to perform better than listeners with one cochlear implant in noise.
(Link to more information about this paper)

The Let Them Hear Foundation have done their own research:

Despite many insurers’ (in the US; my comment) continued erroneous assertions to the contrary, bilateral cochlear implantation is NOT an experimental or investigational procedure, and is medically necessary.  Bilateral cochlear implantation in children has been an accepted, mainstream medical practice since 1998.  Over 3000 have been performed, including over 1600 on children.

Several studies have shown that there is a vast improvement in sound localization ability in patients with bilateral cochlear implants.  In particular, the group of subjects who received a significant amount of improvement when bilaterally implanted were those who were initially implanted at a very early age, as Andrew was.  In September 2005, an international consortium of cochlear implant specialists published an article in the widely respected journal “Acta Oto-Laryngologica” formally recommending that all children with permanent bilateral profound hearing losses receive bilateral cochlear implants.  A recent publication by industry-leading otologist Dr. Robert Peters stated that:

Provision of binaural hearing should be considered the standard of care for hearing-impaired patients whenever it can be provided without significant risks. In severe to profoundly hearing impaired individuals, this can only be provided with bilateral cochlear implantation when hearing aids are inadequate. In carefully selected candidates, the benefits derived are significant, the surgical procedures well tolerated, and negative effects infrequent in both children and adults.

A second recent paper by well-known communications disorder specialist Dr. Ruth Litovsky concluded that: Bilateral CIs can offer a combination of benefits that include better ear effects, binaural summation/redundancy effects and binaural unmasking. These effects have been illustrated in numerous patients world-wide; continued work in this field will no doubt lead to further improvements and increases in the size of each of these effects, for adults and for children.Please refer to the following publications for additional information.

Another medical benefit of bilateral cochlear implantation is that it has been shown to improve speech recognition in noisy environments.  It is expected that once that a patient’s hearing with the second cochlear implant in place is maximized, they will notice a significant improvement in understanding speech in noisy environments.  Comprehending speech amidst background noise occurs commonly in real-life situations, especially in classroom settings and learning environments, at the dinner table, or while talking in a car or on a plane.  Please refer to the following studies for more details:
read more from their conclusions here…..

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!

 

Read the rest of this entry »

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.

Sudoku vs. cognition

What in the world could the term Cognition have to do with Sudoku? Well, let me explain…

For a Sudoku to be solved, you need to be able to learn, reason and remember numbers. Most of which has to do with the term “cognition” (click the word above for a precise terminology).

I learned about my own cognitive condition from doing a lot of Sudoku the past years. For instance I learned that having poor sleeping over longer periods made my Sudoku solving ability very poor. Also if I was plainly tired from a long day, my Sudoku skills suffered. Other things that made Sudoku hard for me to solve was the (for the time being) ever present fatigue, tinnitus and level of blood sugar.

After I became quite skilled in Sudoku, I recognized variations in my own mental performance. And soon it became apparent to me that my mental performance also followed certain patterns. And this is the interesting part that made me want to share this with my readers.

Sudoku taught me when I was tired in a time where I was always tired, if that makes sense??? It’s the fatigue-thing I’m talking about… How did THAT help me? Well, there was variations of tiredness over time. Some days I just couldn’t remember from 5 minutes earlier, or I had trouble concentrating on the task at hand (I have a special routine for solving them). And since I was all about getting better, noticing the good or bad days for Sudoku gave me an external method of measurement of my mental state in a period where my own built-in sensor needed calibration, so to speak 🙂

Sudoku taught me how to trust and USE my own sense of tiredness again. The feeling of tiredness is a signal to ourselves to slow down, to take a break, to eat and drink, to sleep or take a nap and so on…

Yes, I was truly f***ed up, I had lost the ability to heed the signals my own body and mind gave me… Sudoku helped me almost in a scientific way to regain that.

I continue to do Sudoku, allthough not as much as I used to, but it is still a fine tool for measuring my own cognitive skills. And I can recommend Sudoku to everyone as mental training. It has been and continues to be useful to me, not only as a tool for mental measurement but also as hobby that trains my cognitive skills somewhat… And we all could do with better brains, right?