How Are Audiometry Tests Interpreted?

Audiometry tests are hearing tests that characterize the nature of your hearing loss. The purpose of these tests is to generate an audiogram – a visual output that an audiologist can use to diagnose your level of hearing loss. This output can then form the basis of any hearing loss treatment, such as the type of hearing aids you should use. 

What Does an Audiogram Output Look Like?

During a typical audiogram, your audiologist will ask you to wear a pair of headphones and then get you to listen to a series of pure tones. These sounds will range in both frequency and volume, with some loud and high-pitched and others soft and low-pitched. You job is to tell the audiologist when you can hear a sound. They will then use this information to complete the audiogram, giving you a profile of the type of sounds you can hear and those you can’t. 

Your audiologist may also provide a bone conduction test, designed to activate the small vibration-conducting bones in your middle ear. This test uses an oscillator to activate the mastoid bone behind the ear. It is useful when you want to detect a possible cause of hearing loss. 

The output of an audiogram looks like a regular graph, plotted on X and Y axes. On the X axis, is the pitch ranging from low to high, and on the Y is the decibel level. Visually, you can break the audiogram down into four distinct regions. The top left is low pitch, soft noise, the top right is high pitch, soft noise, the bottom left is low pitch, loud noise and the bottom right is high pitch, loud noise. 

On the graph, you will also see two lines – a blue line for the left ear, and a red one for the right ear. Audiologists may denote the two lines O and X. 

Reading An Audiogram

Reading an audiogram isn’t as tricky as you might think. You don’t have to have a degree in mathematics to understand it. 

To read an audiogram, all you have to do is look at the lines. These tell you when you first detected a sound at various frequencies. When interpreting the results, remember that the Y axis starts at the origin at zero decibels. Nobody can hear sounds in this range because there are no sounds.

A healthy audiogram should show that you are able to hear sounds roughly equally well in both ears across the frequency range between 10 and 20 decibels. If you can’t detect sounds in any part of the range above 25 decibels in either ear, it could indicate hearing loss. 

Once you understand the principles behind audiograms, they are generally easy to interpret. People of average hearing ability can hear sounds across the range between 10 and 20 decibels. Those with exceptional hearing might be able to go below this level, but it is rare. 

However, sometimes, the lines go above this range. When they do, your audiologist will talk to you about the severity of hearing loss. If you can hear sounds in the 25 to 29 decibel range, your audiologist may diagnose you with mild hearing loss. A person with this type of hearing loss can typically make out what other people are saying, even if there is a lot of background noise. 

If you can only hear sounds over 40 decibels, then you may have what professionals call moderate hearing loss. People with this level of hearing loss need a hearing aid to be able to follow a conversation. 

Severe hearing loss occurs when a patient can’t hear sounds above 70 decibels. Most people with severe hearing loss must use sign language to communicate with others, even if they wear hearing aids. 

The last category is profound hearing loss. Patients in this category cannot hear sounds below 90 decibels. Many cannot hear any noise at all. 

You may find that after your audiometry test your results aren’t a straight line across all frequencies. This outcome is common. Many patients struggle with specific frequencies, usually high ones. You might find that your audiogram drops off as it gets to the higher part of the range. Furthermore, many people have a good ear and a bad ear so you may notice that the red and blue lines diverge from each other in places. 

If you would like to learn more about audiometry tests and how to interpret them, you can learn more at Ascent Audiology & Hearing by calling 360-515-9948.