What is the Sensory System?
The sensory system is a part of the nervous system that is responsible for processing information through the senses.
The sensory system is composed of the brain, spinal cord, and neurons. It is the neurological wiring by which we recognise and process sensory information from outside and inside the body.
All the sensory systems work together to provide a person the “optimal level of arousal” which means a person is able to recognise, process, and react to sensory stimuli and information in a timely manner.
When a person has a sensory overload, an overstimulation of one or more of the body’s senses, or is sensory under-sensitive, seeking more sensory stimulation, this is often referred to as sensory processing difficulties or sensory processing disorder. This means that their brains are “wired” differently and have difficulties in processing sensory input.
What are the 8 Senses?
1. Visual System
The sense of sight. Information like colour, shape, orientation and motion are received through the eyes.
| Visual Avoiding Behaviours | Visual Seeking Behaviours |
| Covers eyes, or squints out lights | Stares at bright light, flickers, or direct sunlight |
| Avoids bright light or sunlight | Stares at moving objects |
| Withdraws from participating in group movement | Moves and shakes head during writing or fine motor activities |
| Scared of moving objects | Holds items close for inspection |
| Avoids direct eye contact | Seems unaware of new people/things in an environment |
| Frequent headaches, dizziness, or nausea when using sight | Has difficulty focusing on stationary objects |
| Unaware of contrasting colours | Frequently loses the place on a page |
| Seems clumsy due to being unaware of objects in a path | Seeks visual stimulations such as spinning, patterns, fans and fences |
| Unable to determine distance | |
| Rubs eyes |
2. Auditory System
The sense of sound. Information received through the ears. This includes hearing, listening, and being able to filter the information auditory stimuli.
| Auditory Avoiding Behaviours | Auditory Seeking Behaviours |
| Cries, screams or becomes angry at sudden noises | Prefers loud music |
| Has strong emotions when noise volume increases | Seems to always use an “outside voice” or shouting |
| Covers ears or hides in social situations | Puts musical instruments right next to the ears |
| Avoids everyday noises such as toilet flushing | Makes loud noises in quiet settings |
| Bothered by high pitched noises such as whistles, and violins | Enjoys loud music or noises |
| Distressed by metallic sounds such as silverware clinking | Craves common noises such as an air conditioner, a fan or water flowing |
| Seems to be calmed by noises or certain music |
3. Tactile System
The sense of touch. The information is received through the skin.
| Tactile Avoiding Behaviours | Tactile Seeking Behaviours |
| Avoiding certain textures or clothing | Prefers tight clothing |
| Avoids or dislikes messy play | Always seems dirty/messy |
| Distressed by certain clothing such as tight pants, seams in socks, and new textures | Not aware of being touched by others |
| Extremely ticklish | High pain tolerance |
| Dislikes getting face and/or hands washed | Likes to touch everything or has the need to touch everything |
| Avoids hugs or physical contact | Craves vibrations |
| Fearful of large crowds | Likes to hit, push, or pinch other people/children |
| Anxious or over excited over light touch | Constantly touching things around them |
| Dislikes hair brushing, washing, or drying | Likes hair brushing, washing, or drying |
| Does not like certain foods or a picky eater | May crave certain strong flavors such as sweet, salty |
| May only walk on toes | Constantly puts objects in the mouth |
| May refuse to walk barefoot |
4. Olfactory System
The sense of smell. Sensory input is obtained mainly through the nose.
| Olfactory Avoiding Behaviours | Olfactory Seeking Behaviours |
| Avoids particular smells | Smells objects that seem “odd” |
| Become irritated or frustrated around certain smells | Enjoys strong scents |
| Tend to resort to fight or flight methods | Prefer foods with strong smells |
| Gags with certain foods or smells | Can’t avoid smelling things often |
| Avoids familiar foods due to smell | Doesn’t notice dangerous smells |
| Foods don’t taste appealing | Prone to eating/drinking dangerous items due to the inability to smell “danger” |
| Telling other people they stink | Trouble identifying smells of foods |
| Avoids public places | Smells objects constantly |
| Does not like being hugged or close to other people | Smells people constantly |
5. Gustatory System
The sense of taste. It is associated mainly with the tongue, although there are taste (gustatory) receptors on the palate and epiglottis as well. Currently five tastes are recognized, including sweet, salty, bitter, sour, and umami (savory taste or the taste of protein).
| Gustatory Avoiding Behaviours | Gustatory Seeking Behaviours |
| Picky eater, often with extreme food preferences; i.e., limited repertoire of foods, picky about brands, resistive to trying new foods or restaurants, and may not eat at other people’s houses) | Licks, tastes, or chews on inedible objects |
| May only eat “soft” or pureed foods past 24 months of age | Prefers foods with intense flavour; i.e., excessively spicy, sweet, sour, or salty |
| Gags with textured foods | Excessive drooling past the teething stage |
| Has difficulty with sucking, chewing, and swallowing; may choke or have a fear of choking | Constantly chews on hair, shirt, or fingers |
| Resists/refuses/extremely fearful of going to the dentist or having dental work done | Constantly putting objects in mouth past the toddler years |
| Only eats hot or cold foods | Acts as if all foods taste the same |
| Refuses to lick envelopes, stamps, or stickers because of their taste | Can never get enough condiments or seasonings on his/her food |
| Dislikes or complains about toothpaste and mouthwash | Loves vibrating toothbrushes and even trips to the dentist |
| Avoids seasoned, spicy, sweet, sour or salty foods; prefers bland foods |
6. Proprioceptive System
Proprioceptive System is one of the internal senses that allows you to know where your body parts are and what they are doing without necessarily looking at them. This sense is detected through sensory receptors in the joints, muscles, and other connective tissue.
| Proprioceptive Avoiding Behaviours | Proprioceptive Seeking Behaviours |
| Appears to be lazy | May seem clumsy by running into objects, walls or people constantly |
| Avoids active activities such as running, jumping, climbing, etc | Uses extreme force |
| Can be a picky eater | Stomps, walks loudly |
| Prefers to sit still | Poor Body awareness |
| Avoids touch from others | Kicks, bites, and hits |
| Seems uncoordinated | Poor personal space |
| Needs to do familiar activities | Prefers tight clothing |
| Has difficulty in using stairs | Chews on clothing, pencils, finger nails |
7. Vestibular (or movement) System
This is another internal sense that is located in the inner ear. Vestibular sense provides information related to movement and head position. Which is essential for balance, coordination, eye control, attention, being secure with movement and some aspects of language development.
| Vestibular Avoiding Behaviours | Vestibular Seeking Behaviours |
| Scared of Movement activities | Unable to sit still |
| Fearful around playground equipment such as swings, stairs, etc | Needs to be in constant motion (fidgeting, rocking, swaying, spinning) |
| Fearful of elevators | Likes to move constantly |
| Dislikes being turned upside down or picked up | Can be very impulsive |
| Can appear clumsy or uncoordinated | Can’t get enough movement |
| Can appear stubborn | Runs everywhere, instead of walks |
| Avoids stairs or holds on tightly with both hands on the railing | Takes unsafe risks both inside and outside |
| Prefers to be upside down or hang off a couch or chair |
8. Interoceptive System
Another internal sense that allows us to notice internal body signals like a growling stomach, racing heart, tense muscles or full bladder. When we notice these body signals our brain uses them as clues to our emotions.
| Interoception Avoiding Behaviours | Interoception Seeking Behaviours |
| Experiences pain in the body with stress and anxiety | Has little awareness of their own body in space |
| Overly aware of digestive discomforts | Unaware of bowel discomforts and will often has accidents |
| Complains frequently about any discomfort | High tolerance for pain or does not experience normal pain |
| Often has pain, discomfort, headaches and muscle ache | Unaware of being hungry or dizzy |
So there you have it! Just when you thought we only had 5 senses, we infact have 8! At Happy Dots, Paediatric Occupational Therapists can help integrate the senses through what we call a “sensory diet” in which a series of activities are tailored to your child to allow them to remain “calm but alert” throughout the day across a range of different environments. If you have any questions, or wish to discuss the above further, please do not hesitate to contact us on (02) 4959 8920.
