Before we can start thinking about children’s hearing loss and hearing tests, and what the results can mean, it’s important to understand more about sound and its measurements, to get a good grasp on what noises exactly a little one might be missing if they are diagnosed with hearing loss. Having a little bit of knowledge about the science behind sound can really help us to better understand hearing loss, and knowledge is power!
The sound we hear is created by sound waves – vibrations that cause changes in air pressure. The human ear can cope with a range of sounds from high to low intensity or high to low frequency and hearing will change over time, but there are normal thresholds that audiologists’ hearing tests will measure against.
The three main aspects of sound are shown below:
Pitch of sound is measured in Hertz and can also be described as ‘frequency’. An example of a high frequency sound could be the sound of the birds singing and a good example of a low frequency sound could be the sound of thunder.
Volume is measured in decibels (dB) and can be defined as low intensity (quiet) or high intensity (loud).
Frequency and intensity of sound vary much more widely than most people would realise. In everyday life, we pick up sounds that alert us to what is happening, and provide us with a warning to happily anticipate or even to beware of something. For example, a toddler may learn that the rattling of the cutlery drawer means that they can look forward to eating soon, or when they are older, perhaps, the faint low frequency hum of a car can help them to be more alert in crossing the road. The sounds around us help us to anticipate events and make sense of what is going on, and without them, life can be very different.
In a child’s world, sound is highly invaluable in developing communication and speech. Even within the voice of one speaker, many different pitches and volumes are used in every day speech. For a child to develop speech and language, they need to be exposed to a vast range of different sound frequencies and intensities. Different letters have different pitches and even everyday sounds will vary in volume and pitch. When you first discover your child has hearing loss, you may be overwhelmed with thoughts and worries of what they are or are not hearing. Graphs such as seen below to show letter sound thresholds can help to clarify things a little.
Once you have the basics on sound, audiology appointments can be far less daunting and knowing the facts can help you feel more confident in making decisions on how to treat hearing loss and support your child in the best way possible.
Now you have a firm understanding of the basics of sound, you can move on to understand how sound and hearing thresholds are measured in your child’s hearing tests…