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You’ve just completed your hearing test. The hearing specialist is now coming into the room and provides you with a chart, like the one above, except that it has all of these symbols, colors, and lines. This is intended to show you the exact, mathematically precise features of your hearing loss, but to you it might as well be written in Greek.

The audiogram creates confusion and complexity at a time when you’re supposed to be focusing on how to strengthen your hearing. But don’t let it trick you — just because the audiogram looks confusing doesn’t mean that it’s difficult to comprehend.

After looking through this article, and with a little vocabulary and a handful of basic principles, you’ll be reading audiograms like a pro, so that you can focus on what really is important: better hearing.

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

Understanding Sound Frequencies and Decibels

The audiogram is essentially just a diagram 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 fundamental 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 go 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 continue along the horizontal axis to the right, the frequency will progressively increase until it gets to 8,000 Hz. Vowel sounds of speech are usually 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 (shifting from vowel sounds to consonant sounds) while raising the intensity of sound (moving from fainter to louder volume).

Assessing Hearing and Marking Up the Audiogram

So, what’s with all the markings you usually see on this simple chart?

Simple. Start off 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 via headphones, beginning with the smallest volume decibel level. If you can hear it at the lowest level (0 decibels), a mark is created at the junction of 125 Hz and 0 decibels. If you can’t perceive the 125 Hz sound at 0 decibels, the sound will be presented once more at the next loudest decibel level (10 decibels). If you can hear it at 10 decibels, a mark is made. If not, advance on to 15 decibels, and so on.

This equivalent process is duplicated for every frequency as the hearing specialist moves along the horizontal frequency axis. A mark is created at the lowest perceivable decibel level you can perceive for each individual sound frequency.

As for 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 most often applied to mark the points for the left ear; an O is employed for the right ear. You may see some other characters, but these are less crucial for your basic understanding.

What Normal Hearing Looks Like

So what is considered to be normal hearing, and what would that look like on the audiogram?

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

Just take the blank graph, locate 25 decibels on the vertical axis, and sketch a horizontal line completely across. Any mark made beneath this line may reveal hearing loss. If you can hear all frequencies beneath this line (25 decibels or higher), then you most likely have normal hearing.

If, however, you can’t perceive the sound of a specific frequency at 0-25 dB, you very likely have some type of hearing loss. The smallest decibel level at which you can perceive sound at that frequency establishes the level of your hearing loss.

As an illustration, consider the 1,000 Hertz frequency. If you can hear this frequency at 0-25 decibels, you have normal hearing for this frequency. If the smallest decibel level at which you can hear this frequency is 40 decibels, for example, then you have moderate hearing loss at this frequency.

As an overview, here are the decibel levels connected with normal hearing along with the levels linked 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 signals of hearing loss look like? Seeing as the majority of cases of hearing loss are in the higher frequencies (referred to as — you guessed it — high-frequency hearing loss), the audiogram would have a downwards sloping line from the top left corner of the graph sloping downward horizontally to the right.

This indicates that at the higher-frequencies, it requires a progressively louder decibel level for you to perceive the sound. And, given that higher-frequency sounds are connected with the consonant sounds of speech, high-frequency hearing loss weakens your ability to comprehend and pay attention to conversations.

There are some other, less familiar patterns of hearing loss that can turn up on the audiogram, but that’s probably too much detail for this article.

Testing Your New-Found Knowledge

You now know the fundamentals of how to read an audiogram. So go ahead, book that hearing test and surprise your hearing specialist with your newfound talents. 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.