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How to Read Your Audiogram at Your Hearing Test

Audiogram

You have just finalized your hearing test. The hearing specialist is now entering the room and presents you with a graph, like the one above, except that it has all of these characters, colors, and lines. This is designed to provide you with the exact, mathematically precise attributes of your hearing loss, but to you it may as well be written in Greek.

The audiogram adds confusion and complexity at a time when you’re supposed to be directing your focus on how to enhance your hearing. But don’t let it mislead you — just because the audiogram looks perplexing doesn’t mean that it’s difficult to interpret.

After looking through this article, and with a little vocabulary and a few basic principles, you’ll be reading audiograms like a expert, so that you can concentrate on what actually matters: better hearing.

Some advice: as you read the article, reference the above blank audiogram. This will make it much easier to understand, and we’ll cover all of those cryptic markings the hearing specialist adds later.

Understanding Sound Frequencies and Decibels

The audiogram is basically just a chart that records sound volume on the vertical axis and sound frequency on the horizontal axis. (are you having flashbacks to high school geometry class yet?) Yes, there’s more to it, but at a basic level it’s just a chart graphing two variables, as follows:

The vertical axis documents sound intensity or volume, measured in decibels (dB). As you move up the axis, the sound volume decreases. So the top line, at 0 decibels, is a very soft, faint sound. As you move down the line, the decibel levels increase, representing progressively louder sounds until you get to 100 dB.

The horizontal axis records sound frequency, measured in Hertz (Hz). Starting at the top left of the graph, you will see a low frequency of 125 or 250 Hz. As you move along the horizontal axis to the right, the frequency will steadily increase until it hits 8,000 Hz. Vowel sounds of speech are ordinarily low frequency sounds, while consonant sounds of speech are high frequency sounds.

So, if you were to begin at the top left corner of the graph and sketch a diagonal line to the bottom right corner, you would be increasing the frequency of sound (progressing from vowel sounds to consonant sounds) while increasing the level of sound (moving from softer to louder volume).

Assessing Hearing and Marking Up the Audiogram

So, what’s with all the marks you usually see on this basic chart?

Simple. Begin at the top left corner of the graph, at the lowest frequency (125 Hz). Your hearing professional will present you with a sound at this frequency by way of headsets, beginning with the lowest volume decibel level. If you can hear it at the lowest level (0 decibels), a mark is created at the intersection of 125 Hz and 0 decibels. If you are not able to hear the 125 Hz sound at 0 decibels, the sound will be presented once again at the next loudest decibel level (10 decibels). If you can perceive it at 10 decibels, a mark is created. If not, advance on to 15 decibels, and so on.

This same technique is reiterated for every frequency as the hearing specialist travels along the horizontal frequency line. A mark is produced at the lowest perceivable decibel level you can perceive for every sound frequency.

Regarding the other symbols? If you see two lines, one is for the left ear (the blue line) and one is for the right ear (the red line: red is for right). An X is typically used to mark the points for the left ear; an O is applied for the right ear. You may discover some additional characters, but these are less essential for your basic understanding.

What Normal Hearing Looks Like

So what is deemed as normal hearing, and what would that look like on the audiogram?

Individuals with normal hearing should be able to perceive each sound frequency level (125 to 8000 Hz) at 0-25 decibels. What would this look like on the audiogram?

Take the blank graph, find 25 decibels on the vertical axis, and draw a horizontal line all the way across. Any mark made under this line may signify hearing loss. If you can perceive all frequencies beneath this line (25 decibels or higher), then you very likely have normal hearing.

If, however, you can’t perceive the sound of a particular frequency at 0-25 dB, you probably have some type of hearing loss. The lowest decibel level at which you can perceive sound at that frequency pinpoints the tier of your hearing loss.

For instance, consider the 1,000 Hertz frequency. If you can perceive this frequency at 0-25 decibels, you have normal hearing for this frequency. If the minimum decibel level at which you can perceive this frequency is 40 decibels, for instance, then you have moderate hearing loss at this frequency.

As an overview, here are the decibel levels correlated with normal hearing along with the levels correlated with mild, moderate, severe, and profound hearing loss:

Normal hearing: 0-25 dB

Mild hearing loss: 20-40 dB

Moderate hearing loss: 40-70 dB

Severe hearing loss: 70-90 dB

Profound hearing loss: 90+ dB

What Hearing Loss Looks Like

So what might an audiogram with marks of hearing loss look like? Since many cases of hearing loss are in the higher frequencies (labeled as — you guessed it — high-frequency hearing loss), the audiogram would have a downwards sloping line from the top left corner of the chart sloping downward horizontally to the right.

This means that at the higher-frequencies, it requires a increasingly louder decibel level for you to experience the sound. Furthermore, given that higher-frequency sounds are linked with the consonant sounds of speech, high-frequency hearing loss impairs your ability to comprehend and follow conversations.

There are other, less frequent patterns of hearing loss that can appear on the audiogram, but that’s probably too much information for this entry.

Test Your New-Found Knowledge

You now know the fundamentals of how to read an audiogram. So go ahead, book that hearing test and impress your hearing specialist with your newfound abilities. And just imagine the look on their face when you tell them all about your high frequency hearing loss before they even say a word.

This entry was posted on Sunday, April 19th, 2015 at 9:00 am. Both comments and pings are currently closed.