Hearing Loss Demonstrator

I wish I came across this many years ago…

HearLoss is an interactive Windows PC program for demonstrating to normally hearing people the effects of hearing loss. With HearLoss you can replay speech, music and noise under a variety of loudness, filtering and masking conditions typical of hearing impairments. Best of all you can interactively change the settings and demonstrate their consequences.

hearloss

Description

The HearLoss program plays back pre-recorded audio samples of some speech, some music and some typical background noise, either singly or in combination. As it replays, three sliders control a simulation of the effects of three common consequences of hearing loss: loss in amplitude sensitivity, reduction in frequency range, and loss in spectral detail. Changes in the amplitude sensitivity slider changes the loudness of the sound, changes to the frequency range slider changes the upper frequency limit of the sound, while changes to the spectral detail slider changes the amount of fine structure present in the spectrum.

http://www.phon.ucl.ac.uk/resource/hearloss/

Suggestions for Use

This is one way you might use the program to demonstrate the effects of hearing loss to normally-hearing people:

  1. Start the music playing and adjust levels so that the audience can hear it clearly. Stop the music.
  2. Explain that deafness is not just all or nothing, but that hearing impairments come in various degrees.
  3. Play music and demonstrate loss in amplitude sensitivity to mild, moderate and severe losses.
  4. Repeat for speech. Point out that difficulty in hearing speech affects our social interactions – we can’t follow what is going on in a group conversation, for example.
  5. Explain that if hearing loss was just a loss in sensitivity, then we could restore peoples’ hearing with just an amplifier.
  6. Explain that most hearing loss is not just a drop in quantity but also a dop in the quality of sound perceived. In particular the kind of hearing impairment asoociated with old age has associated changes in frequency range and spectral detail.
  7. Play music and demonstrate what a reduction in frequency range means: at mild, moderate and severe levels.
  8. Repeat for speech. Point out that even if the speech were loud enough, the loss of high frequencies makes it harder to understand.
  9. Play music and demonstrate the consequences of a loss in spectral detail. The effect of this slider is like looking at an out-of-focus photograph – you can’t see all the fine detail. Get the audience to listen as you bring the slider back to normal – you should hear the signal getting "clearer".
  10. Play speech and noise simultaneously with sliders set to normal. Point out that the speech is still fairly easy to understand.
  11. Add a moderate loss of frequency range and spectral detail. The speech is pretty unintelligible now, although it becomes a bit clearer when the noise is turned off. Hearing impaired people find listening in conditions of noise far more difficult than normally hearing people.

Copyright

HearLoss is not public domain software, its intellectual property is owned by Mark Huckvale, University College London. However HearLoss may be used and copied without charge as long as the program remains unmodified and continues to carry this copyright notice. Please contact the author for other licensing arrangements. HearLoss carries no warranty of any kind, you use it at your own risk.

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.

What I hear (or what’s left)

It would be a good idea for me to put down some kind of status as to how my hearing is these days (as a baseline):

Without my hearing aids I can barely hear:

  • My son singing at certain notes at the top of his voice (gives me echo-effect on that frequency until I hear new sounds)
  • A tractor right outside my windows (5 meters away)
  • Only the bass from music

keep-silence With hearing aids in quiet surroundings I hear:

  • Well enough to understand spoken words with the aid of lipreading (better if my head is clear and rested)
  • When really silent: a noisy refrigerator, traffic noise outside the building, an airplane or helicopter in the sky. I get a “white noise” sound from running water.
  • My external hard-drive – the spinning disks vibrate into the wooden table.
  • Other peoples voices in the room, but cannot understand without lipreading.
  • Familiar voices on the mobile for short conversations and messages. I most often have to repeat and ask for confirmation. It’s border-line.
  • Other peoples footsteps in same building, maybe a slamming door.
  • Static noise from electrical FM-devices like my Phonak Smartlink

With hearing aids in a “quiet cafe” surrounding I can hear:

  • Spoken word if not more than 1 meter away, but I have to concentrate really hard
  • Other people speaking, but cannot make out what is said.
  • Music, but only in the form of unrecognised sounds…

 With hearing aids in noisy surroundings I hear:1728

  • All sounds are garbled and mixed in an impossible soup of noise
  • I can extract a voice from 50 cm away if noise isn’t too bad, and I know the subject and the person (if I’m used to lipread whomever, it’s a better chance of understanding)
  • Cars and trucks travelling at high speed close by me
  • Dogs barking loud

When waching a movie with sound directly into my hearing aids I am dependant on captioning. Environmental sounds like running water (splashing), wind blowing, birds chirping etc are lost completely. Spoken words are not understood at all without captioning (dialogue is most often switching and camera angles changing too fast for lip-reading to be effective enough).

Music has lost it’s magic during the last few years. I can sense the rythm, and hear most of the bass and drums. Percussion is completely gone. Perception of vocals depends on type of music and what tone the voice has. Guitar has disappeared slowly last few years, now it’s not “swinging” at all anymore…

I wrote down this, because I want to use it to compare later when I get the CI (my personal baseline).

Making sense of the world through a cochlear implant

PET20YEAROLD_HIGH March 13, 2007 –  Scientists at University College London and Imperial College London have shown how the brain makes sense of speech in a noisy environment, such as a pub or in a crowd. The research suggests that various regions of the brain work together to make sense of what it hears, but that when the speech is completely incomprehensible, the brain appears to give up trying.

The study was intended to simulate the everyday experience of people who rely on cochlear implants, a surgically-implanted electronic device that can help provide a sense of sound to a person who is profoundly deaf or who has severe hearing problems.

Using MRI scans of the brain, the researchers identified the importance of one particular region, the angular gyrus, in decoding distorted sentences. The findings are published in the Journal of Neuroscience.

In an ordinary setting, where background noise is minimal and a person’s speech is clear, it is mainly the left and right temporal lobes that are involved in interpreting speech. However, the researchers have found that when hearing is impaired by background noise, other regions of the brain are engaged, such as the angular gyrus, the area of the brain also responsible for verbal working memory – but only when the sentence is predictable.

“In a noisy environment, when we hear speech that appears to be predictable, it seems that more regions of the brain are engaged,” explains Dr Jonas Obleser, who did the research whilst based at the Institute of Cognitive Neuroscience (ICN), UCL. “We believe this is because the brain stores the sentence in short-term memory. Here it juggles the different interpretations of what it has heard until the result fits in with the context of the conversation.”

brainxrayThe researchers hope that by understanding how the brain interprets distorted speech, they will be able to improve the experience of people with cochlear implants, which can distort speech and have a high homer-simpson-wallpaper-brain-1024level of background noise.

“The idea behind the study was to simulate the experience of having a cochlear implant, where speech can sound like a very distorted, harsh whisper,” says Professor Sophie Scott, a Wellcome Trust Senior Research Fellow at the ICN. “Further down the line, we hope to study variation in the hearing of people with implants – why is it that some people do better at understanding speech than others. We hope that this will help inform speech and hearing therapy in the future.” 

In sickness and health

Coming from a lot of resting and relatively no stress I can feel somewhat energized. But the feeling of fatigue is less than one hour away still, and that can be frustrating. But I have come to terms with the fact that this is how it is – for now anyway. And I feel that I’m getting better a little at a time. I hope it’s not just wish-thinking…..

Yesterday I came down with a regular cold. Comes with the season, and especially when you have kids roaming in germ factories like schools.

All hearing aid users probably know this: being hard of hearing makes you a extra deaf when being “stuffed” and having to blow your nose every ten minutes or so… But for people who do not know how it is to be hard of hearing and use hearing aids, it’s virtually impossible to understand the impact of a common cold on hearing aids users. This is what I want to try and explain now.

When common cold occurs, one is likely to get an increase in internal pressure in the neck/throat region due to various swollen glands. This in turn puts pressure on internal organs in the head, hence headaches, light-sensitivity and REDUCED HEARING. When the cochlear has more internal fatigue-736871pressure where the hair-cells are situated, the gel-substance that carries the sound waves to the hair-cells is a little less sensitive. That means that the overall amount of energy that reaches the hair-cells in cochlear is being reduced.

Then there’s also the impact of all the fluids that forms in the sinuses.
With reduced hearing in the first place, such an reduction on the hearing gives a larger effect on hard of hearing, thus making us more deaf.

Aside from the normal symptoms of common cold that makes you tired, feverish and so on, it also makes near deaf’s have to put even more energy into the business of communicating.

I propose that near deaf need an extra low threshold for sickness leave from work etc. It is also important that the employer understand the fact that common cold has a stronger impact of people with hearing disability.

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Dreaming deafness

Woke up early today from a vivid dream…Behind Closed Eyelids

I was at a banquet or an award show or like, and the hostess and host of the show somehow pointed me out among a lot of people and started making their way towards me.
That would normally be the last thing I would wish for, as I have had a lifelong fear of appearing stupid in case I answered wrong. (you know, if I didn’t hear the question properly, I would answer something else, thus making it funny for everyone…)
With microphones jammed up in my face and spotlight zooming in on me along all the attention from everyone present, they started asking me easy questions I was able to answer ok, you know, to warm me up… 
Then the guy came “to the point” and halfway into his question I lost him completely. That would be where I normally wanted to sink into the ground and die of shame or embarrassment. In this dream I just said: “I’m sorry, I didn’t hear you.” Being very calm inside, laid back and not stressed, I waited for their next move. Somehow the social pressure on me was gone, because they had a show to pull off, and by picking me the “joke” was on them. I could see the guy lost his nerves and didn’t know what to do. At such instances I feel terribly sorry for the person, and want to help, but in this situation they were interviewing me, and I could not help by taking charge of the conversation as I normally would.
The woman stepped in for a try and she failed too…. then I woke up, wide awake…

This was a weird good dream for me. Can’t remember last time I had a dream about being out there publicly. And the thing that hits me about this dream is that I’m just being me and honest about it (that I can’t hear everything), unlike before in my life, where I’d have a number of strategies for “handling” such a situation, thus “saving face”. Doesn’t matter what kind of situation I’m in, I’m who I am… Near deaf and all 🙂

I think this dream was some kind of milestone for me.