Our senses facilitate us to learn about the world. Sensory processing is the ability to process sensory information that you are receiving in order to engage with the world around you. Sensory input is constantly being processed from both the external and the internal environment.
For example: As you sit reading this information, you are receiving various sensory input from the external environment such as; visual feedback from the electronic screen, visual processing of the words on the screen, noises from your house – voices, electronics, outdoor sounds, the feeling of clothing on your skin, the weight of your body against the chair, the temperature in the room and so on. Additionally, you are receiving information from internal sensations such as your muscles controlling your posture, noticing whether or not you are hungry or thirsty and SO much more! If your brain is processing the information correctly, you are able to process them without much thought or attention, essentially you are able to “tune out” of these sensations and “tune in” or focus on what you are reading.
Over responsive vs Under responsive
Children that present with sensory processing difficulties might appear over-responsive and/or under-responsive to certain types of sensory input.
Some children need very little information to register a sensation. To these children, a little sensory information may seem like a lot. We can think of them having a ‘small cup’ and requiring only a small amount of sensory information to fill their small cup.
Over-responsive = Little cup
If their little cup starts ‘overflowing’ (they have registered so much sensory information that they find it overwhelming), we then often see a reaction or behaviour. This could be a ‘fight’ response such as screaming, shouting, hitting or crying, or it could be a ‘flight’ response such as running away, covering their ears or hiding.
Some children need a lot more sensory information to register a sensation. To these children, a lot of sensory information may seem like a little. We can think of them having a ‘big cup’ and requiring a much larger amount of sensory information to fill their big cup.
Under-responsive = Big cup
Under-responsive children miss cues, such as verbal or visual instructions, or struggle to coordinate movements, as the sensory information they are receiving is not enough for them to register it. Therefore they may respond by either seeking more information in order to register it, such as jumping, running, banging hands on tables or spinning in circles, or appear ‘daydreamy’ and under aroused.
However, when the ‘just right’ amount of sensory information is received, the child is able to register this and respond effectively.
Tactile System – The tactile system is one of the largest sensory systems. This is the very first sense to form, with development at around 8 weeks of gestation. The largest amount of tactile receptors are found in our mouth, hands and feet. Touch plays an important role in our ability to learn about and interact with the environment around us. We use touch to discriminate textures, temperature, pain, light and deep pressure touch.
Proprioceptive System – The proprioceptive sensory system is our body awareness and tells us where our body is in space. The receptors are in our muscles and tendons in our joints. Feedback from this system tells us how much force we are using when manipulating objects. Proprioception can provide a calming effect on our nervous system, helping us to feel better and can increase our productivity by waking us up.
Vestibular System – The vestibular system tells us how and where we are moving, by letting us know if our movements are up, down, fast, slow, angular or circular. Our vestibular system also tells us where our head is in space and helps with balance. The vestibular receptors are in our inner ear. This system feeds into our ability to feel awake or feel sleepy, known as our arousal level.
Visual System – When we look at the visual system in regards to sensory information, we are not thinking about whether the child can read a letter on the wall 5 meters away or if a child can see the TV, what we are thinking about is what the child can perceive and whether this makes the child alert or calm. Visual input can have both alerting and calming effects. Variations in light, color and number of visual distractions contribute to attention level. Increasing or decreasing visual input during tasks can help maintain effective arousal levels for learning and doing in the classroom and home settings.
Auditory System – When thinking about the auditory system, we usually recommend that children have their hearing tested if there are any concerns, to rule out medical conditions. Auditory feedback is the ability to detect sound waves through the ear canals and this feedback can have an alerting or calming effect.
Gustatory System – Also known as our ability to taste. We have 5 different taste receptors, salty, sweet, bitter, sour and umami (savoury or meaty), on our tongue, soft palate, and cheek. From the time we are born, we know how to use oral motor input to calm us and to learn about our environment.
Olfactory System – Also known as our ability to smell. Olfactory receptors are found in our nose. The olfactory system is one of our most primal sensory systems as it helps us to detect safety e.g. mothers scent and danger e.g smoke from fire. Olfactory input can be highly emotive as it can remind us of memories, both good and bad, as the processing centre for this information in the brain is situated close to our memory centre.
Interoceptive system- Our interoceptive system refers to our internal bodily cues. We have receptors in the organs inside our bodies that send signals to our brain to tell us when for example: our bladder is full, when our stomach is empty, when we are feeling too hot or if we are thirsty. This system motivates us to take action to meet our internal bodily needs, therefore when our stomach tells us we are hungry, we will get up to seek food.