A Hearing Loss & Late Deafened Blog

How To Read Your Audiogram

In audiogram, Hearing Loss on June 19, 2008 at 1:04 am

Last month I completed a project on audiograms for a class. Realizing many people with hearing loss don’t understand what all the symbols mean, I thought I’d condense it into a blog. I am not an audiologist, nor an “expert” on audiograms. I’m just a person with hearing loss, so if something doesn’t make sense, I suggest you ask your audiologist. This is just a very short, simplified overview. I’ve also included links at the bottom for further reading.

In order to understand an audiogram, first you need to understand sound. There have been entire books written about sound alone, but I’m going for simplicity here.

Why does a frog sound different from a bird? Sounds vibrate at different speeds. Low sounds vibrate more slowly than high sounds. Here’s an illustration of low frequency sound (on the top) vs high frequency (on bottom).

The frequency at which sounds vibrate is measured in hertz. The audiogram only tests pure pitch. In real life most sounds aren’t purely one pitch.

The pitches tested on an audiogram may range from 125 hertz to 8000 hertz. The vertical lines of the audiogram indicate pitch. 125 hertz is a low-pitched sound, while 8000 hertz is high-pitched.

The piano above is a great way to represent low-pitched vs high-pitched sounds. Of course many sounds are lower than the lowest piano key. Likewise many other sounds are higher-pitched than the highest piano key. Additionally, there are pitches between each key, and so on. Audiologists do not measure every single pitch known to man, they only measure the pitches at certain intervals to give them an idea of how hearing loss might be affecting you.

You already know some sounds are loud and some soft. A loud bus can sound soft in the distance. It becomes louder as it gets closer. It is the same sound near or far, only the intensity has changed. The loudness of a sound (intensity) is measured in decibels (dbs). Below, the horizontal lines of the audiogram represent the loudness of sounds (decibel intensity).

This makes perfect sense if you think about it. When you turn the volume up on your cd player, the pitch of the music you’re listening to stays the same. You’ll recognize a piece of music whether the volume is high or low, unless it’s too low to hear. Intensity levels measured on audiograms range from about 5 dbs (very soft) up to 110 or 120dbs (very loud).


Putting it all together, your audiogram may look like this if you have good hearing:

Everything above the blue line (the hearing threshold) is what you don’t hear. Everything below the line is what you hear. This audiogram above represents good hearing because the hearing threshold falls at or above 10dbs in all the pitches tested.


Now let’s look at the “speech banana.”

I like this picture with illustrations of where sounds fall on the audiogram. The speech banana is important to audiologists, since understanding speech is what sends most people to the doctor. This banana illustrates the range of human voice and where some phonemes of the English language fall. It isn’t perfectly accurate of course because all voices are different. However, you can see how the speech sounds fall in different areas of the audiogram. ‘M’ and ‘u’ are usually nasally lower pitched sounds, while ‘f’ and ‘s’ are high-pitched sounds.

Some people place the number of English phonemes at around 40, however others say it’s impossible to know how many phonemes there are because of all the different English dialects. Additionally, some people speak a blend of English dialects. Your hearing threshold and exposure to various dialects can impact understanding when you have hearing loss. Also, when you lost your hearing– if you lost hearing pre-lingually as opposed to post-lingually– makes a difference.

Further, individuals all differ in speech comprehension. Two people with the exact same hearing thresholds may not hear exactly the same way. This can be hard for some to understand, but think about runners. All feet are different. Some people have flat feet, some don’t, some people are bow-legged, some may have scar tissue from old injuries, some legs are short and others long. Many factors determine how fast you run. It’s the same with hearing. Many factors determine how well you understand the sounds you hear besides measurements plotted on your audiogram. There are differences in how all your parts work together, as well as voices you’re used to and dialects, and many other variables.

When people lose their hearing they don’t necessarily lose all their pitches equally. In fact, a common type of hearing loss is the “ski-slope” where low tones remain intact, while high tones drop. There’s also a reverse ski-slope, “cookie bite” and reverse cookie bite.

Why does this happen? If you look at the picture of the cochlea below, you will notice different areas of the cochlea are responsible for detecting different frequencies.

Often the nerves in only one area of the cochlea are damaged, while other nerves remain healthy. A similar analogy would be experiencing numbness in just one part of your leg after having a bad accident.


During sickness, parts of the cochlea may become damaged. Those parts may not react to sound unless amplified. When a hearing loss becomes severe to profound, amplification may no longer do the job adequately. A person can begin to experience pain with loud amplification while simultaneously unable to hear– especially when other parts of the cochlea still work just fine. The cochlea has become dysfunctional.

Below is an example of the common ski-slope hearing loss. The slope can be steeper or less steep. Notice the severe hearing loss at 6000 hertz, but “normal” hearing at 250 hertz. Without hearing aids, this person will hear ‘m’ and ‘u’, but not ‘f’ or ‘s’. Listening to speech becomes a constant game of fill-in-the-blanks.



What do the x’s and o’s mean??

The circles indicate measurements for the right ear.

The x’s indicate measurements for the left ear.

What are the brackets? While the “air conduction” test determines hearing threshold (the blue line below), audiologists also perform a bone conduction test, with a vibrator placed near the cochlea. This can help the audiologist determine whether there’s a problem with the cochlea or some other part of the ear. The brackets indicate the results of the bone conduction. They usually look like this > but sometimes they look like this ].

Below there’s a disparity between the bone conduction and air conduction results. The cochlea seems to be working fine, as shown by the brackets. In this case, doctors determined it was due to infection of the middle ear.

For Further Reading:

http://www.hearingresearch.org/Dr.Ross/Audiogram/Audiogram.htm

http://www.audiologyawareness.com/

http://www.drmehr.org/audiograms.html

http://www.earinfo.com/how-to-read

Pictures:

1) http://www.dkimages.com/discover/previews/739/175616.J

2) http://www.pacificaudiology.com/audiogram/a_pitch.GIF

3) http://www.pacificaudiology.com/audiogram/a_loud.GIF

4) http://www.pacificaudiology.com/audiogram/a_sounds.GIF

5) http://www.audiologyawareness.com/hearinfo_agnormal.asp

6) http://cache.eb.com/eb/image?id=14298&rendTypeId=4

7) http://www.bayareahearingservices.com/nss-folder/pictures/

audiogram.jpg

8) http://www.audiologyawareness.com/hearinfo_agconduct.asp

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  1. This is a really interesting posting. On my audiogram, there was very little sound. I really find it interesting the sounds in the cochlea. I never knew that. The only normal sound I ever had was in the 200hz and 400hz. Now I understand. Keeps me thinking.

  2. Thanks SO much for posting this! You know, I’ve been getting my hearing tested for 40 years and nobody ever explained an audiogram to me. I really had no idea how to read one.

    Great post!

    ~ Wendi

  3. you mean the middle ear-it would make no sense to say it was an infection of the inner ear, if the choclear is working. It has to be an infection of the middle ear.

  4. PS- The middle ear is bypass during the bone conduction test. If the test (bone conduction test) comes back the same as the air conduction test, then we know the problem is an inner ear.

  5. Are you reading my mind??? One point I am focusing on is getting really oriented on the specifics of my hearing loss so that I can check and balance everything my “new” audiologist tells me, and maybe I can get some answers once and for all. I have had so many conflicting accounts from audiologist throughout the years that it isn’t a wonder I don’t know what to believe, at times.

    All of the information you have included is old hat to those of us who have had hearing loss for years (over 40 for me), but having it whittled down to the basics here on the blog makes it so much easier to get your head around. Thanks!!

  6. Thank you for this, I learned so much at first read, and am printing this out to digest it further. Much thanks

  7. Blu1– Thanks for pointing out my error. I’ve corrected it. You’re quite right. The cochlea is part of the inner ear. If the bone conduction results are normal, hearing loss may be due to a problem with the middle-ear. This is common with children who experience frequent ear infections.

  8. By the way- you did a great job explaining a very complex subject. Thank you.

  9. Excellent explanation, Kim. I really appreciate your taking the time to post this. I’m sure it will be very helpful to anyone who is new to hearing loss!

  10. This was excellent Kim. I’ve had hearing loss for 60 yrs now and this is the first time I’ve really understood the audiogram.

  11. Thanks for all the comments. I’m glad this helped. I’ve been wearing hearing aids for over 25 years, and learned a lot while doing this project. For example, I never understood the purpose for the bone conduction test. I wanted to share what I learned with others.

    Still– if you find this unclear or have any questions, I recommend you talk to your audiologist.

  12. Nice information. what is hard is that black background is somewhat hard to read the words as well as to print all that black ink is also not good, too. Hope you can modify the colors for better reading and printing.
    Thanks.

  13. Sorry Dann, but the background of the actual article is white. don’t know why you’re seeing it in black?

  14. nice one !! really worth reading even for qualified doctors…

    simple and clear explanation.

  15. I am experiencing a lot of discrimination, due to my hearing loss as well as my age. At 62 I still am in good shape except for my hearing. Is there any help fighting this discrimination especially in the employment sector. I have Bilateral Sensorineural hearing loss and it seems like employers go out of their way to not hire me. Thank You J.

  16. Jay – I am wondering if you are able to prove that you are being discriminated in the workplace. If so, there are laws to protect you. However, if it’s just a hunch that you have re: discrimination and employment, I don’t know if there is anything you can do. I am looking for a job, and I feel I have a steeper hill to climb in my job search, simply because of my hearing loss and the lack of understanding about it from a potential employer’s point of view. Good luck!

  17. Jay,

    It’s quite possible you qualify for job seeker assistance related to your hearing loss and/or age. Check with your state WorkForce Office to see if there is a program in place.

    Also, most states have Deaf Hard of Hearing Services and they usually work together with the WorkForce Office to provide any special equipment, etc., that someone with hearing loss might need in the workplace.

    We all know employers are not permitted, by law, to discriminate against someone based on their hearing loss or age, but it happens. Unless you can prove discrimination, then there isn’t a whole lot you can do about it.

    Looking for work, paired with an advocate, might alleviate some of the concerns employers might have with regard to your hearing loss and age. Having others on your side, helping to assure that you are capable to do the job might make the difference. It’s worth a try.

  18. Hello Jay,
    Your delima is a huge one crossing the nation. I’ve found no areas of services for hearing loss (medical, tech creations, sales of such, soc. services) where any part of the learning included understanding of LDA’s (late deafened adults and hoh after the age of 19). So, society wise, the ignorance of our life and needs is rampant.

    I could give you a lot of agencies, groups, etc to call but I’ve called them many times over the years with no support or specifics to help me continue my independant living. But, there are many things you can do towards your problem. I just need more information. Also, think of each time, in detail, where your job would require hearing and in what form.

    What state are you in? What type of jobs are you seeking? Are you totally deaf, hoh, know a little ASL, sign fluently? Can you communicate one on one, in a small group, on the phone etc.?

    It would be helpful for you if you started your request for help with a separate heading. I doubt people will find you under audiology. I found you cause someone copied/pasted to a shared listgroup with me. There is much to suggest back and forth but first start with the above.

    I await your reply.

  19. Hi Jay, I think what Trudy meant was if you posted comments to our current post as it is on the front page, but it’s fine to comment here. The Dept. of Vocational Rehab is a federal program designed to help people with hearing loss and other disabilities to find jobs.

    Different states call it different things “Work Force”, Bureau of Rehabilitation Services, Vocational Rehabilitation,. . .”

    Do a google search by your state and vocational rehab, and you should find your state’s webpage. If nothing else, they can generally help with job search. They will also work with your employer to educate about the laws regarding accommodations for the hearing impaired.

  20. The hardest part of asking for accommodations at work – or anywhere else – when you are hard of hearing is that the majority of focus of advocates has been skewed towards people who are deaf and work with interpreters. I am not saying this as a negative about the Deaf Community, they spoke up and got noticed. I do think that if we want to see accommodations for people who are hard of hearing, we need to speak up. This is not easy when we are all looking over our shoulder in today’s economy wondering if we are next out the door and fearing that if we make waves we will be next. I do think though we have to begin with Vocational Rehabilitation and other services and tell them I need accommodations to continue to work successfully just as people who are deaf do. My accomodations needs are different, but just as valid. To ignore this is discrimination and government agencies are not allowed to operate that way. I often use this example in my presentations about hearing loss; “I am deaf and you are hearing. We both go to France, but neiter of us speaks/understands French. I cannot hear it and you cannot understand it, which of us is most limited? By the way, if the Frenchman speaks louder, it does not help you or me. So, a pocket talker, FM system, CART, etc. is that I need. Too expensive! Sure, I’ve heard that for years when I encouraged the hiring of interpreters too. Rich-MN

  21. This is clear and concise guide! 🙂

  22. Thank you for a really excellent article on hearing and the audiogram.

  23. Please fix pictures on ‘How to read your audiogram’, it not showing and some of the links are not working. Please correct this.

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