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Levels of deafness

The level of your child’s deafness can be described in terms of their decibel (dB) hearing level, or by the terms ‘mild’, ‘moderate’, ‘severe’ or ‘profound’.

Based on British Society of Audiology definitions of hearing loss, this is the decibel hearing level range each of these terms refer to:

  • mild (21–40 dB)
  • moderate (41–70 dB)
  • severe (71–95 dB)
  • profound (95 dB).

Your child’s audiologist will be able to give you more information about the level of your child’s deafness. They will also be able to explain the sounds that your child can and can’t hear.


All sounds are made up of different frequencies, measured in Hertz (Hz). The frequency of a sound affects the pitch that it’s heard at. For example, the high notes on the right-hand side of a piano keyboard are examples of high-frequency sounds. If your child has a hearing test where the results are plotted on an audiogram, you’ll see low to high frequencies marked along the top.

It’s possible to have the same level of deafness for all frequencies or to have different hearing levels at different frequencies. For example, your child may have more difficulty hearing higher frequency sounds.

Speech consists of vowels (a, e, i, o, u) and consonants (the remaining letters), that are made up of a range of frequencies.

Consonants communicate most of the information when a person speaks and they’re also what make speech intelligible (able to be understood).

Consonants appear in the higher frequencies of an audiogram chart meaning that children need to be able to hear the full range of speech sounds at a quiet level to be able to understand speech.

Your audiologist will be able to explain your child’s audiogram and give you information about the frequencies affected by your child’s deafness.