Sensory processing refers to the ability of our body to receive and understand sensory information from our environment. It forms the foundation from which advanced skills develop and is enhanced in the course of ordinary childhood experiences. The information is brought into our body through our senses which are sight, hearing, taste, touch, smell, proprioception (body awareness) and vestibular (balance) input. As the information is received, our body produces physical responses. These may be to move away from the source of the information as it is dangerous, to maintain attention as it is important or to prepare the body for a fast movement. Some children are unable to respond appropriately as they are receiving the sensory information in a disordered manner. They may perceive the level of information as too high and unpleasant or it may not be strong enough to stimulate a response and it may go unnoticed. This is known as sensory modulation disorder and is more common in children with Autism Spectrum disorder.
The following behaviours may be observed:
A child who is hypersensitive to sensation may;
- Observe to have an exaggerated response to injury
- Dislike bright environments
- Dislike loud music
A child who avoids sensation may;
- Have uncomfortable feelings associated with negative experiences
- Not like being messy
- Withdraw from touch
- Be a fussy eater
A child who may actively seek sensation;
- Has low arousal levels and is trying to increase them by excitatory behaviours (pushing)
- They may be aggressive or crash into people
- They may be unable to sit upright or still
- They may be distracted easily and often fidget
A child who doesn’t register sensation may;
- Have low arousal levels
- Observe to be passive
- Not notice name being called
- Not get dizzy
The vestibular sense is responsible for monitoring motion and speed and provides information to the brain and muscles to enable the body to maintain balance.
Children oversensitive to vestibular input may:
- Become dizzy easily
- Avoid large movements.
Children under sensitive to vestibular input may:
- Observe to seek extra movement experiences such as spinning to produce the sensation
Sensory-based motor disorder describes another area of difficulty experienced in sensory processing. It can be observed in children who have poor postural stability and are unable to coordinate and plan movements (dyspraxia). They are unable to produce smooth movements because the sensory information they receive, although regulated, cannot be applied to create effective movement. These movements are discussed in the Gross Motor Skills and Fine Motor Skills sections.
Sensory discrimination disorder is the third category of sensory processing issues and relates to children with poor perception and interpretation skills. Visually, they may find it difficult to discriminate between shapes or letters. Some children may find it difficult to search through a bag and determine by touch what they have found. Others may be unable to attend to different sounds or acknowledge the source of the sound.