Understanding the audiogram | During the hearing test, two parameters - frequency and intensity - are varied in order to determine the softest sounds your child is able to hear.
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The audiogram is a grid with two scales. The horizontal scale is the "frequency scale". Frequency, which we perceive as pitch, can be described as the different notes on a musical scale.
Frequency is measured in Hertz (abbreviated as Hz). Humans have the ability to hear a wide range of frequencies. In fact, children with normal hearing are able to hear from a very low-frequency sound of 20 Hz (ex: fog horn) to a very high frequency of 20,000 Hz (ex: whistle).
The audiogram shows test results for 6 to 10 frequencies between 250 and 8000 Hz, which are the frequencies that must be heard for development of speech and language. The low frequencies appear on the left-hand side of the grid while the high frequencies appear towards the right side of the grid.
The vertical scale is the "intensity scale". Intensity, which we perceive as loudness, can be described as how loud or soft a sound is. Intensity is measured in decibels (abbreviated as dB or dBHL). This scale shows how "soft" each frequency on the audiogram can be heard. A child with normal hearing should be able to hear each frequency at a level of 20 dB or less.
If the intensity level is higher than 20 dB (appearing more towards the bottom of the grid), this means that the volume of that frequency needed to be raised to this level in order for your child to start hearing, thus indicating a hearing loss at that particular frequency. In sum, each frequency is given an intensity reading.
There are special ways of indicating results for the left and right ears on the audiogram. Readings obtained for the left ear will often be written with blue ink and/or indicated by an "X" while readings obtained for the right ear will often be written with red ink and/or indicated by an "O".
Six degrees of hearing loss |
There are typically six degrees of hearing loss which your audiologist will use to describe your child’s hearing loss at different frequencies:
You should feel free to discuss the audiogram with your audiologist. Ask which sounds (frequencies) and which loudness (intensity) your child is able to hear. This information can give you a good start in understanding your child’s unique way of hearing the world around him or her.
