An audiogram – what it is, what it’s for, how to read it
Written by Francis L’African,
An audiogram is a graph that describes your hearing ability. When you get a hearing test by an audiologist, the results are written on this graph.
How to Read an Audiogram
First of all, you should note that the results of the right ear are represented by O’s and the results of the left ear are represented by X’s. If the graph is printed in colour, the results of the right side are written in red, and those of the left side are written in blue.
The graph is composed of two axes. The horizontal axe represents sound frequency in Hertz (Hz). Frequency means the pitch of the sound. For example, a sound of 250 Hz is a very low pitch sound (like a drum), and a sound of 8000 Hz is a very high pitch sound (like the tweet of a bird). The lower the sound frequency, the lower the sound pitch.
The vertical scale represents sound intensity in decibels (dB). Intensity means the level or volume of the sound, in other words, whether the sound is loud or soft. For example, 20 decibels is the sound level of a whisper while 90 decibels is the sound level of a food processor. The higher the intensity, the louder the sound. See here a decibel scale with various examples of sounds and the decibels they produce.
The O’s and X’s on the audiogram represent how loud a sound of a given frequency must be in order to be heard.
Let’s take the example below. The first red point on the left indicates that: On the right ear (red O), the volume must be upped to 40 decibels (vertical scale) for the person to be able to hear a sound of 250 Hertz (horizontal scale). This same example indicates that on the right ear, the volume must be upped to 50 decibels for the person to be able to hear a sound of 1000 Hz and the volume must be upped to 75 dB for the person to be able to hear a sound of 8000 Hz.
So, as you can tell, the lower the points are on an audiogram, the lower the hearing is (sounds have to be louder in order for the person to be able to hear them).
What’s a Normal Audiogram?
Hearing acuity is considered normal when all the points are above the 25–decibels line, as in the example below. This result means the person can hear sounds from 250 Hz to 8000 Hz (so from very low pitches to very high pitches) at a low level (≤25 dB).
What is it for?
An audiogram’s purpose is to illustrate your hearing configuration and, if applicable, the type and severity of your hearing loss.
If you have hearing aids, it is very important to determine the amplification prescription you need to adequately adjust your hearing aids.
If you have a disease affecting the ears (e.g.: otosclerosis), getting regular audiograms allows to follow the progress of the disease.
Also, some employers and certain organizations require them as a condition of employment.