8 sensory systems: how the brain perceives the world

Important right away. At school they teach about 5 senses, sight, hearing, touch, taste, smell. This is the basic classification.

In occupational therapy and sensory integration, 8 systems are distinguished. Because there are three more "internal" ones that are usually not talked about. And it is exactly these that often explain what parents call "strange behavior."

5 "external" systems

1. Auditory

Reaction to sounds. Voices, household noises, sirens, music.

• Hypersensitivity. The child covers their ears from ordinary sounds. The vacuum cleaner is fear. Loud music is panic. Rebels in the store.
• Hyposensitivity. Does not react to a voice. Seems "not to hear." May make a lot of noise themselves.
• Sensory seeking. Talks loudly, bangs things, holds their mouth near the speaker.

In daily life. Noisy places, festive gatherings, kindergarten, typical triggers.

2. Visual

Reaction to light, movement, contrast.

• Hypersensitivity. Afraid of bright, flickering light. Gets tired in a busy room. Covers their eyes.
• Hyposensitivity. Does not notice changes in lighting. Comes close to the screen.
• Sensory seeking. Loves flickering, spinning, mirrors. Fascinated by bright objects.

In daily life. Classrooms with multicolored posters, neon lighting, shopping malls.

3. Tactile

Touch, textures, skin temperature.

• Hypersensitivity. Avoids hugs. Cries when washing hair, getting a haircut. Complains about clothing (seams, labels).
• Hyposensitivity. Does not feel when dirty. Does not notice a cut. Seeks strong touch.
• Sensory seeking. Snuggles up to things. Hugs strongly. Strokes different textures.

In daily life. Clothing, hygiene, washing, hugs. Frequent conflicts are right here.

4. Taste

Taste, texture, temperature of food.

• Hypersensitivity. Eats only 5-10 products. Refuses new food. Makes a face at sour, bitter.
• Hyposensitivity. May eat very spicy or very hot food. Does not notice a bland taste.
• Sensory seeking. Chews clothing, pencils, inedible objects. Seeks strong tastes.

In daily life. Food selectivity. Often mistakenly perceived as "stubbornness."

5. Smell

Odors.

• Hypersensitivity. Runs from perfume, smoke, household chemicals. Cannot eat if something "smells bad."
• Hyposensitivity. Does not notice strong smells. May not react to the smell of smoke.
• Sensory seeking. Smells everything around, people, objects, food.

In daily life. Transport, the kitchen, someone else's home, festive gatherings with perfume.

3 "internal" systems

These are the ones often forgotten. And they explain the most "strange" behavior.

6. Vestibular

Balance, movement in space, head orientation.

• Hypersensitivity. Afraid of swings, carousels, high stairs. Does not like fast movements. May vomit in transport.
• Hyposensitivity. Often seems "hyperactive." Constantly moves, because the brain needs more signals.
• Sensory seeking. Jumps, spins, hangs on a swing without tiring. Loves fast movements.

In daily life. Transport, swings at the playground, escalators, active games.

7. Proprioceptive

Sense of the body, muscles, joints. Force of pressure, position of the body.

• Hypersensitivity. Flinches from light touches. Soft hugs hurt.
• Hyposensitivity. Bumps into furniture. Does not notice how hard they squeeze objects. Falls off the chair.
• Sensory seeking. Seeks "heavy work." Pulling, pushing, carrying. Strong hugs. Sitting in a corner under a blanket.

In daily life. Coordination of movements, sitting at the table, games with other children.

This is often the most useful system for self-regulation. "Heavy work" (carrying heavy things, pushing, jumping) helps organize the nervous system.

8. Interoception

Signals from inside the body. Hunger, thirst, pain, the need for the toilet, heartbeat, fatigue.

• Hypersensitivity. Reacts strongly to minor discomfort. Complains of hunger, pain immediately.
• Hyposensitivity. Does not notice hunger, thirst, fatigue. May not notice a full bladder. Does not report pain.
• Sensory seeking. Listens to the heartbeat, taps the stomach. Seeks internal sensations.

In daily life. The toilet, regular meals, reporting pain or illness.

This is one of the hardest sides to "notice," because it is from within. Often the child simply seems "nervous for no reason," but actually does not notice they have been hungry for 5 hours.

What to do with this

First, do not diagnose on your own. This is the work of an occupational therapist with an assessment.

Second, observe. What type of reactions does your child have in which systems? Write down specific examples. This is material for any future consultation.

Third, adapt daily life. Details are in the material "Sensory support at home."

An important detail

One child may have different profiles in different systems at the same time. Hypersensitive to sounds, but hyposensitive to tactile signals. Or vision is normal, but strong vestibular seeking.

That is why there is no "one program for all." Each child has their own combination.

What is next

Read "Sensory overload: meltdown vs tantrum," about how the 8 systems together create overload.

And "Sensory support at home: what is safe," specific actions for each of the systems.