We’re all familiar with the Marvel Cinematic Universe and the Avengers, right? An ensemble of superheroes coming together to stop formidable foes who threaten our world. Well, our sensory systems operate in the same way.
Each sense has their own set of responsibilities but will team up with one another to understand what’s going on around us and how to appropriately respond. This collab is known as sensory integration.
Sensory integration (SI for short, also known as sensory processing) refers to the processing, integration, and organization of sensory information from our body and the environment. This process allows us to participate in day-to-day functions, from self-care to socializing.
The SI Protocol
Sensory processing is complex and instantaneous. It involves reception, detection, integration, modulation, discrimination, postural responses and praxis.
Reception and Detection. Sensory receptors are located throughout the body (skin, muscles, eyes, ears, nose, and mouth). These receptors take in information from the outside world and travel from the peripheral nervous system (PNS) to the central nervous system (CNS). From there, the CNS takes notice of these incoming messages. Think of it as your own personal Spidey sense…
Integration. The CNS then gathers the intel and directs it to where it should go, decoding and cataloging the data by matching it with past stored information and attaching meaning to it. The more sensory systems are involved, the more accurate and intricate the data will be, allowing for a more efficient and appropriate response. Your S.H.I.E.L.D. (Strategic Homeland Intervention, Enforcement and Logistics Division).
Modulation. This is the brain’s regulation of sensory input. This function also allows us to self-regulate. Modulation is different for everyone. What one person may find novel and interesting, another may view it as familiar and boring. Modulation adjusts the flow of sensory information into the CNS, like a faucet. The different forms of modulation are:
- Excitation – Alerting sensory messages, helping us determine if something is pleasant (continue the action), unpleasant (stop action), or a threat (flight-fight-fright response)
- Inhibition – Filtering out irrelevant sensory information to focus on meaningful ones
- Habituation – When information that was initially important no longer is as it becomes more frequent (varies between individuals)
- Sensitization – When the brain interprets sensory input as important, even the common and mundane ones (seen in those who have sensory sensitivities)
When excitation and inhibition are balanced, we can make smooth transitions from one state to another. This is how you decide if you are a Bruce Banner or a Hulk.
Discrimination. This is the ability to determine the qualities, similarities, and differences between sensory stimuli. As your child grows and develops, they learn to use their senses for organized and purposeful behavior.
In a nanosecond, the brain completes its process of obtaining, integrating, and filtering out incoming sensory messages. The result is when the brain sends outgoing commands preparing the body to act, involving postural responses and praxis. Your brain = Your Jarvis.
Postural Responses. This is when the child’s head, neck, and trunk extend upwards against the pull of gravity. This upright position allows us to use both sides of the body (bilateral coordination) and to try different body positions in different planes. You know Tony Stark doesn’t have good posture, that why he has the Iron Man suit.
Praxis (aka Motor Planning). This is the ability to ideate, plan, and execute voluntary actions to novel tasks. Mastering new skills lead to building blocks of new skills. For example, you can’t run without learning how to walk. The more your child does, they more they can do, resulting in an adaptive response (the ability to adjust actions to fit situational challenges).
The Sensory System Roster
Our five external senses, plus three internal senses, make eight total:
- Interoception – internal body sensations coming from our organs, notifying us if we’re hungry, sleepy, or needing to use the restroom.
- Vestibular – a powerful brainstem sensation that lets us know where we are in relation to the ground and the objects around us (are we upside down, are we moving, are we going to fall, etc).
- Proprioception – a brainstem sensation that gives us body awareness, telling us the location of our body parts and how they are moving relative to one another (for example, your right hand is holding your phone in front of you while your left hand scrolls through social media while walking).
- Tactile – a brainstem sensation that alerts us about what is in contact with our body and its properties, like pressure, weight, temperature, movement, size, shape, or if it’s painful
- Visual – a cortical sensation that informs us of what we are seeing regarding the location, distance, color, shape, and movement of figures.
- Auditory – a cortical sensation that allows us to locate, decipher, and discriminate sounds.
- Olfactory – a chemical sensation that gives us information about odors/smells.
- Gustatory – a chemical sensation that lets us know about what enters our mouth.
By taking in all the data delivered by these systems, we’re able to make sense of our surroundings and formulate a desired response. It’s especially effective when these systems work together.
Team ups are significant. One sensory system can only gather so much intel, but two or more can allow us to make better decisions and create meaningful memories, both for learning and nostalgia.
For example, taste can only determine the four basic flavors (sour, bitter, salty, sweet) of food. However, the sense of smell fills in the other “flavors”, while touch provides the understanding of the meal’s physical traits (crunchy, soft, mushy, tough, etc).
Another very important alliance involves the tactile, proprioceptive, and vestibular systems. Together, this trinity helps us establish a physical awareness of self, gain a feeling of safety, attend to activities, move without fear, and to complete a variety of motor tasks on a daily basis, from getting dressed to catching a ball.
When it All Goes Awry
Like in all super teams, synergy makes a big difference. When one sense is having an off-day, the other systems may have to pick up the slack. But what if their off-day becomes consistent?
- Touch. When this system is off, it can interfere with how your child engages with their surroundings. Tactile sensitivity can affect the proprioceptive and vestibular systems, making it uncomfortable moving limbs or engaging with their environment. That limited movement can affect how they motor plan, understand the physical properties of objects, or comprehend the meaning of words.
- Vestibular. Because this system has many connections with the other senses, it can impact how your kid moves within their environment (proprioception), what they hear (auditory), or how they visually attend to tasks (visual).
- Proprioception. When body awareness is lacking, other senses like touch and vision are heavily relied on to manipulate items or coordinate movement, like brushing teeth or eating.
- Visual and Auditory. Because these systems are higher level than others, they can be affected when the vestibular and proprioceptive senses are out of sorts. For example, if there’s fluid in the ears, it not only influences how someone hears information but also their perception of balance.
All is Not Lost
There is no cookie-cutter method on how to handle sensory issues since every child’s brain interprets information differently. However, by allowing your little one to explore, get hands-on with their environment, and move their bodies freely, you may reduce the chances of a sensory situation that inhibits their ability to participate at home, at school, or with others.
If you frequently observe times where your child may be avoiding, seeking, or not even noticing things in their environment, a sensory issue may be the culprit. Talk to your pediatrician who can refer you to an OT trained in sensory processing.
What is Sensory Integration? (sensoryintegrationeducation.com)
Barker, L. (2012, August 25). Sensory Processing: Behavior, Memory and Learning. Live lecture. Children’s Healthcare of Atlanta, Atlanta GA.
Kranowitz, C. (2005). The Out-of-Sync Child: Recognizing and Coping with Sensory Processing Disorder. New York, NY: A Perigee Book.
Delaney, T. (2008). The Sensory Processing Disorder Answer Book: Practical Answers to the Top 250 Questions Parents Ask. Naperville, IL: Sourcebooks, Inc.