It is well understood that many on the autism spectrum experience challenges with processing a range of sensory information. In this blog I would like to cover aspects of autism that relate to auditory processing and how these can impact upon daily life.
Auditory processing is often described as ‘what we do with what we hear’. If you think of a hearing test at the Doctors or in hospital, this uses pure tone sound to check at what volume we can hear higher and lower sounds. Being able to ‘hear’ sound is clearly very important but it does not tell us much about auditory processing! If you are old enough to remember the test card on the BBC in the UK, this pure tone sound at around 400Hz was only one frequency and is actually quite uncomfortable to listen to. I'm sure this would have been deliberately designed to wake you up to go to bed!
Natural sound is a complex mix of many frequencies that arrive at our ears together with millisecond time differences and variations in volume. To communicate and function well in daily life, we need to be able to take all the sounds in our environment, process or ignore them as appropriate, and develop meaning. This is as important for environmental sounds such as bird song, motorbikes or the crying of a baby, as it is with speech. Many on the spectrum have challenges with gaining meaning from the world of sound we hear every day.
Sound is the primary sense for survival. If you consider that vision and hearing are our ‘far’ senses that keep us safe, sound works in the dark, through walls and is also 360° around our body. This means it is vital for our sense of security. Sound affects the nervous system in a fundamental way and can put us on alert and in fight and flight mode very easily. Your child may react strongly to unexpected sounds such as a hand dryer or toilet flushing which can cause a meltdown. Lucker and Doman (2019) discuss how this hypersensitivity is related to pathways between the ear and the emotional system in the brain. This is not a challenge of hearing but of auditory processing and emotional regulation.
Sound reaching our ears only has 4 components that can change. These are: -
1. Where is the sound coming from? – sound localisation
2. How loud is it? - volume
3. Can I process the tiny timing differences in sound? – temporal processing
4. Is it a high or low sound and can I process the changes? – pitch or frequency
One or all of these can be affected in autism. You can imagine if your brain cannot work out where a sound is coming from, this leads to problems processing sound. Many will resort to wearing headphones to reduce the amount and volume of sound although this is not something that will retrain the brain to process sound more effectively.
We also often find that many on the spectrum hear sounds that others do not perceive. These sounds can be disturbing, and we would not even know they are there. Look at this spectragram which was recorded in the departures lounge at Manchester Airport. You can see the solid white line at around 20,000Hz. Whilst this is inaudible to most people, some on the autism spectrum would hear this and react negatively. If you sometimes see sudden changes in behaviour and emotional stability, this is an important area to consider.
Another area that research shows can be a challenge is that of steady beat and rhythm. This not only affects our ability to listen and concentrate, but also affects movement.
Many children and adults with autism love music and a strong beat. A really good bass beat can be grounding for the body and give us a sense of stability and something to hang on to in a disorganised world. Much research shows that an unstable brain response to sound is a feature for many on the spectrum. It is no surprise that seeking out music and beat is something that helps with this grounding.
These auditory processing difficulties are developmental and can often be helped by specific auditory stimulation. There are a range of auditory programmes available to help with building communication, attention and auditory processing skills. The Listening Program® is one example of these. TLP has been shown to reduce hypersensitivities to sound as well as improve other areas as diverse as auditory processing and toilet training. You can see a number of these studies at https://www.learning-solutions.co.uk/research
Whilst of course there can be no guarantee of progress, programmes such as The Listening Program can help with the development of auditory skills, improving the awareness and processing of volume, time, pitch and spatial aspects of sound. These are fundamental to the development of speech, communication skills and social awareness.
By Alan Heath. Psychologist and Director of Learning Solutions
Alan is the International Representative for Advanced Brain Technologies in the UK and Eire and the developer of TAVS (Test of Auditory and Visual Skills) and The Movement Program.
Lucker J.R., Doman, A. Use of Acoustically Modified Music to Reduce Auditory Hypersensitivity in Children. 2019. Vol. 11 (1) Music and Medicine