Ever wonder what exactly an audiogram is, or how to read one? Well, you're in luck. Welcome to Audiogram 101—your crash course “guide” to understanding the audiogram results of your hearing evaluation.
What is an audiogram?
Put simply, an audiogram is a chart that displays the results of your hearing test(s).
Performed by a licensed hearing care professional, a hearing test determines how loud a sound needs to be for you to hear it 50 percent of the time. These results are compared against normal ranges, and any results that go outside the normal ranges may indicate hearing loss.
The results shown in an audiogram can help a hearing care professional determine:
- the type of hearing loss you may have
- the degree of your hearing loss
- which ear(s) the hearing loss affects
- what sounds you may be missing
Hearing tests involved with an audiogram
Let’s talk about some of the specific hearing tests that the audiogram may reflect. These can include:
- Pure tone air conduction test: You will listen to a series of tones played at different frequencies (or pitches) through over-the-ear headphones or insert earphones. The test will measure how loud each frequency needs to be for you to barely hear it. (This is known as your hearing threshold.)
- Pure tone bone conduction test: Your hearing care professional may also place a device on the bone behind your ear that plays tones via vibrations, at different frequencies. This test will measure how loud each vibrating frequency needs to be for you to barely hear it. This test helps the professional determine what type of hearing loss you may have—sensorineural, conductive, or mixed.
Your hearing care professional may also perform other tests covering speech recognition and speech discrimination—however, these results are not shown on the audiogram. Regardless, the professional will guide you through them alongside your audiogram results.
How to read an audiogram
After all hearing tests are complete, the hearing care professional will walk you through the audiogram results. To help you feel more prepared and in-the-know of what to expect from your audiogram, here are some of the basics—what the audiogram looks like, the information it shows, and what it all means (examples included).
Audiogram layout
Here’s how the audiogram graph is laid out:
- The top (or bottom) horizontal portion of the audiogram labeled “Frequency (Hz)” lists the different frequencies/pitches that are tested. These are measured in Hertz (Hz) and range from 125–8000 (“8K”), low to high.
Real-life frequency examples (outside the hearing test): High-frequency sounds could include a child’s voice, whistle, or softer consonant sounds. Low-frequency sounds could include thunder, a bass drum, or louder vowel sounds.
- The left-hand vertical portion of the audiogram labeled “Intensity (dB HL)” measures how loud each frequency needs to be for you to hear it 50 percent of the time. This is measured in decibels (dB HL) ranging from -10–110 dB HL. (Did you know -10 dB HL is not silence or the absence of sound? If you were born with normal hearing, it is likely you began with thresholds at or below 0 dB HL.)
Real-life decibel examples (outside the hearing test): High-decibel sounds could include a chainsaw or siren. Low-decibel sounds could include a whisper or light rainfall.
Symbols on the audiogram (aka “the legend”)
Let’s explore the symbols you’ll likely see on the audiogram after your hearing evaluation.
- X: This represents your LEFT ear during the pure-tone air conduction test.
- O: This represents your RIGHT ear during the pure-tone air conduction test.
When “X” and “O” are plotted on the audiogram, they are showing each specific ear’s hearing threshold—in other words, the minimum loudness a frequency must have for each ear to hear it.
- <[: Shown together or separately, each “bracket” represents your RIGHT ear during the pure-tone bone conduction test.
- >]: Shown together or separately, each “bracket” represents your LEFT ear during the pure-tone bone conduction test.
When these “brackets” are plotted on the audiogram, they are again depicting each specific ear’s hearing threshold. (Remember, these results are important because they help determine what type of hearing loss you may have.)
- Various letters (e.g. p, ch, sh, e, i, etc.): These are not actually results from your hearing evaluation (and may not appear on every audiogram) but rather a counseling tool used by the hearing care professional after your tests are complete. This arrangement of common English sounds (known as the “speech banana”) are plotted where they would typically range in frequency and intensity when someone is speaking to you. Particularly if hearing loss is detected on the audiogram, the professional can use the "speech banana" to show what speech sounds you may have difficulty hearing.
Understanding audiogram results (thresholds)
While your hearing care professional is your best resource for explaining your audiogram results in-depth, here are some basic guidelines and examples to help give you a general understanding of your hearing test outcomes as shown on the audiogram.
Threshold results
The audiogram results of a pure tone air conduction test use this rule of thumb:
- A normal hearing threshold—or the minimum level of sound heard with normal hearing—is up to 20 dB. Any threshold that measures at an intensity of 25 dB or louder is considered a hearing loss.
In the Figure A audiogram example, the normal threshold for hearing is shaded so you can see the comparison between normal hearing and the audiogram results for each ear. (You’ll notice that the results fall both inside and outside the normal threshold range.)
According to this example, the person has normal hearing thresholds for frequencies between 250–1000 (“1K”) Hz—in both ears. However, for thresholds above 2000 Hz (“2K”), there is a mid- and high-frequency hearing loss—again, in both ears.
The letters within the “speech banana” will later demonstrate the speech sounds the person likely has difficulty hearing, due to their hearing loss.
Type-of-hearing-loss results
The general guideline for pure tone bone conduction test results (which help determine your type of hearing loss) is as follows:
- If the pure tone bone conduction results on the audiogram are better than the pure tone air conduction results by more than 10 dB HL and fall within the range of normal hearing, the hearing loss is conductive and usually temporary. It can often be treated surgically or with medicine.
- If the pure tone bone conduction results on the audiogram are within 10 dB HL of the pure tone air conduction results and below the range of normal hearing, the hearing loss is sensorineural and permanent. Most times, it cannot be corrected medically or surgically, but can be treated and improved with the use of hearing aids.
(Remember, you can also have mixed hearing loss—a combination of conductive and sensorineural.)
In the Figure B audiogram example, we see that the pure tone air conduction results match the pure tone bone conduction results, revealing a sensorineural hearing loss.
Again, the letters within the “speech banana” will later demonstrate the speech sounds the person likely has difficulty hearing, due to their hearing loss.
Questions? Ask your hearing care professional
While we hope our Audiogram 101 served as a helpful, simplified guide to understanding your audiogram, remember that your hearing care professional is the best resource for explaining your individual audiogram results. (Keep in mind your hearing evaluation may also include other tests not mentioned here.) They are always happy to explain your audiogram as thoroughly as you need and answer any questions you may have.
With that, we give you an “A+ / 100%” for making it through Audiogram 101! Congrats and all the best at your next hearing evaluation.