Sensory Processing Disorder

Downloadable PDF - What is sensory processing and SPD?

Information adapted from Growing Early Minds

Sensory Systems

There are eight sensory systems:

• Visual (sight) – received through our eyes, and interpreted as things like colour, brightness, shape and movement.

• Auditory (hearing) – our ears receive sound waves and we process them as different frequencies and volumes

• Olfactory (smell) – the odours sensed through the nose

• Gustatory (taste) – such as sweet, savoury and salty

• Tactile (touch) – what we feel with our skin, such as whether things are rough, smooth, cold or hot

• Vestibular (balance) – the sense of where our heads and bodies are in space and control of eye movements

• Proprioceptive (joint position sense) – the sensation of joint and muscle movements and postural control

• Interoception (internal sensing) – the feelings inside our bodies, such as hunger, thirst, and butterflies in the stomach.

Each sensory system sends information to the central nervous system (the spinal cord and brain), enabling us to function effectively and safely. 

The sensory systems work independently, but also interact with each other. For example, smell and taste are closely related – you may have noticed that food loses its taste when you have a head cold. 

Information adapted from Growing Early Minds and Brain Balance

Sensory Processing Disorder

Sensory processing disorder (SPD) is a condition affecting the brain’s ability to receive and respond to sensory information. This causes a misinterpretation of sensory input that leads to altered function.

• Under typical circumstances, the nervous system smoothly receives and interprets signals from within the body and from the outside world. 

• The nervous system uses this information to send out other signals. 

• For example, if you receive a signal that you’re touching something extremely hot, it triggers a signal to remove your hand.

• These signals are important for learning, memory, behaviour, emotions, movement and coordination.  

• A breakdown within the system affects your ability to function.

People with SPD fall into one of two categories:

Hypersensitive (over-reactive) 

These people will be unusually sensitive to sensory input. 

For example:

• lights may seem unbearably bright

• common sounds may be painful

•  clothing labels cause extreme irritation on the skin. 

Children who are hypersensitive may try to avoid sensory input, by running away from situations, for example.

Hyposensitive (under-reactive)

These people are less sensitive to sensory inputs. 

They may:

• seem to have a high tolerance to temperature or pain

• seek out sensory experiences

  • They might repeatedly sniff their food, rub things against their skin, or perform certain movements. 

Because they need more sensory input to become engaged, they may also seem to have a low level of interest in their surroundings.

The poster below gives a brief overview of what Sensory Processing Issues are. Click the top right corner to download a PDF version.