What is the auditory system, and how might difficulties with auditory processing contribute to my child’s areas of difficulty?
The Auditory System explained
The auditory system is the sound or hearing system. It is composed of three parts – the outer ear, the middle ear and the inner ear.
The ear hears many different sounds, through air-conduction and bone-conduction. Sounds must be accurately received by the ear before they can be sent to the relevant parts of the brain to be analysed and acted upon.
Spoken words are received as sound pressure waves. These waves vibrate the ear bones or ‘ossicles’ in the middle ear, the body’s three tiniest bones. The vibrations are then transmitted to the inner ear or ’cochlea’, which is the main organ of auditory perception. Here the vibrations are converted into electrical impulses, then sent to the brain cortex and the temporal lobe where the impulses are interpreted as words. It is at this point that the meaning of the sounds is decoded. Once a meaning is assigned, the brain can evaluate the information and form a response strategy.
The role of the inner ear
The inner ear is made up of the cochlea and the vestibule. The cochlea decodes every sound it receives, while the vestibule is the centre for sensory integration & motor control.
The cochlea and vestibule complement each other. The cochlea deals with short wavelengths characteristic of external sounds. The vestibule attends to long wavelengths produced by physical movement. Without this relationship, it would be difficult to assign meaning to sounds.
The importance of perceiving sound correctly
The auditory system is connected to the entire brain. It influences all levels of the nervous system, particularly the movement system (vestibular), and the visual, proprioceptive and tactile systems (somatosensory). This means there are critical links between listening and hearing, and a person’s ability to organise sensory information, to pay attention, and engage with the world around them.
It is vital that the ear structures work correctly to perceive sound so the inner ear can convert sound into electrical signals for the brain. If this does not occur, the subsequent stages of auditory processing will be affected. The first step when concerns arise about your child’s responses to sounds is to have a hearing test.
Recognising auditory perception difficulties in children
There are two main types of auditory perception differences. Children may experience either or both types of difference. The types are:
- over-responsivity or auditory defensiveness
- under-responsivity, which is a lack of response to an auditory input.
Children who are overly-responsive or defensive to auditory input may:
- Cover their ears at sudden loud or unexpected sounds
- Become distressed by loud or unexpected sounds and have difficulty calming or keeping going with an activity even after the sound has gone
- Experience increased anxiety in anticipation of some sounds, for example, not want to enter the public toilet at the shops because of the hand dryer
- Experience rapid change in their emotions
- Have a strong need for predictability and control
- Have difficulty participating in group activities where there is a lot of talking
- Become unproductive when there is a lot of background noise
- Become hyperactive or appear overstimulated in noisy environments
Children who are under-responsive to auditory input may:
- Appear disorganised
- Seem easily distracted
- Appear impulsive
- Seek out sound and make constant noises such as hum, sing or speak louder
- Appear to tune out or don’t seem to hear when their name is called even though their hearing may be fine
- Have difficulty following instructions
- Have difficulty with awareness of space around them due to not being as aware of where sounds are coming from and the automatic positional information this gives
Children within both categories of auditory perception differences may:
- Appear disruptive in group settings
- Become rigid or inflexible during play or in learning environments
- Can appear withdrawn or turned out in busy environments
- Display inconsistent behaviours, for example, become upset or withdrawn for no apparent reason.
- Tell others to be quiet even though they are being loud themselves
- Present with delays in speech and language
Using Occupational Therapy to improve auditory perception differences
Sensory-based occupational therapy involves activities and programs that promote auditory perception and strategies to address the functional impact of perceptual differences. Therapy includes a selection of sensory activities to complete at home.
During a therapy session, your child’s occupational therapist may engage your child in a listening program such as Therapeutic Listening™ or The Listening Programme™. Therapy also involves trialling the use of adaptive equipment, such as the child wearing hearing protection in certain situations to reduce the level of noise input for the child and the associated anxiety.
Considering and problem-solving changes to the environment around the child and the activity they want or need to accommodate for the child’s auditory needs are also part of the Occupational Therapy process.
Auditory Processing Disorder
Some children experience more difficulties than can be accounted for by auditory perception differences. Auditory Processing Disorder is when children have normal hearing but have difficulty decoding what they are hearing to make sense of it, and subsequent difficulty responding to or remembering what they have heard. Auditory Processing can be assessed by an Audiologist, Speech Therapist, Educational Psychologist or Occupational Therapist with additional training in the assessment and management of this disorder.
If you think problems with your child’s auditory system may be impacting them and you would like to find out more about what can be done to help you can book a Startup Session below or call us on (07) 5578 2000 or to meet with one of our Senior OT’s!