All day we have information being sent to our brain through our senses. There are 8 senses in total and we often think about the first 5; touch, sight, sound, taste and smell. There are three more which are sometimes overlooked which are body movement known as the vestibular system and body awareness known as proprioception. The 8th sense is the most recently discovered sensation called interoception which helps you understand what is going on inside your body.
People who experience sensory processing difficulties may be hypersensitive (over sensitive/over-responsive) or hypo-sensitive (under-sensitive/under-responsive) to certain sensory inputs. If you are hypersensitive/over sensitive then you are receiving too much information through your senses and may want to avoid that input. If you are hypo-sensitive /under-sensitive then you are receiving too little information and you may seek out more of that input.
So let’s take a closer look at each of the senses;
Some people are hypersensitive to touch or what we might call “tactile defensive”. This might mean that a label in a t-shirt feels like a cactus or brushing your hair can be uncomfortable. Some people may seek certain textures by rubbing your hands on rough surfaces or enjoy very soft fabrics. Some people may love light touch like tickling and others may find this distressing.
If you are oversensitive to visual input then you may avoid bright lights or brightly coloured spaces and might prefer dim lit places or find these calming. You might also be easily distracted by movements or decorations when you are trying to concentrate on a task. If you are under sensitive then you might seek out brightly coloured toys or items that spin or light up.
Sensitivity to sound means loud and busy environments can be overwhelming, you might need to cover your ears or be startled easily. For people who are over sensitive to sounds concentrating can be tricky as the humming or whirring of a fan can be difficult to filter out. Being under sensitive to sounds can result in seeking a lot of noise and you may listen to the TV with the volume turned up very high or make a variety of noises such as humming.
Being hypersensitive/oversensitive to taste can have a big impact on your diet, if a little tastes like a lot it can limit the foods you can tolerate. You might prefer bland foods rather than spicy and salty foods or toothpastes can be overwhelming. Licking, tasting or chewing non-edible items may be a sign of being hypo-sensitive/under sensitive to taste. If you are under sensitive to taste you may like excessive amounts of seasoning or spicy food and may enjoy items such a vibrating toothbrushes.
Smells that someone else might not notice may smell overpowering to someone who is oversensitive to smell, this can be very distracting or uncomfortable. The smell of cooking or bathrooms may be mean these places are avoided by someone who is oversensitive to smell. Being under-sensitive to smell may mean sniffing new objects or not noticing foul smelling odours that others would.
Body movement/Vestibular system
The vestibular system helps the body maintain balance and be aware of where we are in space and is related to the systems in the inner ear. Having an oversensitive vestibular system may result in avoidance of play equipment such as slides and swings or being fearful of activities that require balance. You may prefer sedentary tasks, moving slowly and dislike big movements. Having an under-sensitive vestibular system make look like always being on the go and seeking movement such a spinning, jumping and intense movements. Trampolines and swings are a big hit!
Proprioception is very similar to the vestibular system. However, vestibular refers to how we determine where our whole body is in space, while proprioception is keeping track of and controlling each individual body part. An example is to move a finger back and forth; proprioception would make this an easy task. Without proprioception, the brain cannot feel what the finger is doing, and the process must be carried with calculated steps such as using vision to compensate for the lost feedback of the finger.
Someone who is seeking input for their vestibular system may love “squishing” activities or bear hugs, tight clothing and weighted blankets. They may also have trouble knowing how much pressure to apply when writing or stroking animals and may slam doors and drawers closed.
This is the newest and most recently discovered sensation as it comprises being aware of the basic primary functions such as hunger, toileting, and breathing. When a person has interoception difficulties they may not be aware of when they are hungry, thirsty, in pain or the need to go the bathroom.
As always individualised supports such as Occupational Therapy and other clinical supports can be beneficial when figuring out your sensory needs.