Understanding an audiogram can be a bit daunting at first, but it's an essential tool for anyone concerned about their hearing health. Audiograms are used by audiologists to visually represent a person's hearing ability, and learning how to interpret this chart can help you better understand your hearing loss or that of a loved one. This guide will walk you through the basics of reading an audiogram, so you can feel more informed during your next audiology appointment.
What is an Audiogram?
An audiogram is a graph that displays the results of a hearing test. It shows the softest sounds you can hear at different frequencies, measured in decibels (dB) and Hertz (Hz). The results help audiologists determine the degree and type of hearing loss.
The Axes of an Audiogram
-
Horizontal Axis (Frequency in Hertz - Hz):
- The horizontal axis represents the frequency or pitch of sounds, ranging from low frequencies (250 Hz) on the left to high frequencies (8,000 Hz) on the right. Lower frequencies are associated with deeper sounds like a bass drum, while higher frequencies relate to sounds like a whistle.
-
Vertical Axis (Hearing Level in Decibels - dB):
- The vertical axis shows the intensity or loudness of sounds, measured in decibels (dB). It ranges from -10 dB at the top, which represents very soft sounds, to 120 dB at the bottom, representing very loud sounds. The higher the number, the more intense the sound needs to be for you to hear it.
Understanding the Symbols
-
O and X:
- In most audiograms, an "O" is used to represent your right ear's hearing threshold, while an "X" represents your left ear. These symbols are plotted on the graph according to the softest sound you can hear at each frequency.
-
< and > or [ and ]:
- These symbols represent bone conduction hearing thresholds. Bone conduction testing bypasses the outer and middle ear to test the inner ear directly, helping to determine whether hearing loss is sensorineural (inner ear) or conductive (outer or middle ear).
Types of Hearing Loss on an Audiogram
-
Normal Hearing:
- If your hearing thresholds fall between -10 dB and 20 dB across all frequencies, your hearing is considered normal.
-
Conductive Hearing Loss:
- Conductive hearing loss occurs when there is an issue with the outer or middle ear, often due to blockages or infections. On an audiogram, this type of loss is usually indicated by better bone conduction thresholds (represented by < and >) than air conduction thresholds (O and X).
-
Sensorineural Hearing Loss:
- This type of loss, caused by damage to the inner ear or the auditory nerve, shows up as a loss at the same level for both air and bone conduction thresholds.
-
Mixed Hearing Loss:
- Mixed hearing loss is a combination of conductive and sensorineural loss, showing a gap between air and bone conduction thresholds, but with both showing a loss.
Reading the Audiogram: An Example
Let's say your audiogram shows an "X" at 40 dB for 500 Hz and an "O" at 50 dB for 500 Hz. This means that for a sound at 500 Hz, your left ear can hear it at 40 dB, while your right ear can only hear it at 50 dB. If these thresholds stay at similar levels across different frequencies, this indicates a degree of hearing loss in both ears.
What to Do with This Information
Understanding your audiogram is the first step in addressing hearing loss. Discuss your audiogram with your audiologist, who can explain the specifics and suggest the best course of action, whether it's hearing aids, further testing, or other treatments.
