Sensory Processing, Part 1: What is Sensory Processing?

One of our earliest science lessons is about our senses. Coincidentally, sensory needs are often the driving force behind a lot of children’s behavior issues, starting very early in life. To understand sensory needs, we have to understand sensory processing functions and how they drive our behavior.

Our 9 (or Maybe 8) Senses

Wait, what? But there are only 5 senses, right?

Wrong.

Of the traditional 5 senses we’ve been taught, 4 of them are simple. Sight, hearing, smell, and taste are half of our senses. But the sense taught to us as touch is actually much more complicated. Because we have many different kinds of nerve endings in our skin, we have the ability to detect and process both light touch and deep pressure sensations. While some people group these 2 senses together, for the purpose of managing needs I think it’s important to think of these as 2 different senses. There’s also a sense of proprioception, which is the feeling of the body in space and in relation to other objects, and a vestibular sense, which is the feeling of spinning and balance. Plus, we have to include interoception, the feeling of what is going on inside our bodies.

So with sight, hearing, smell, taste, light touch, deep pressure, proprioception, vestibular, and interoception, that’s 9 senses.

Sensory Volume

I’m sure we’ve all disagreed with family members about the volume of the TV. That’s a product of having different sensitivities to sound. Some people hear the tiniest squeak in the car engine. Others don’t hear anything until the engine falls out.

Likewise, our other senses have a set “volume” at which we are comfortable. Too quiet, and we aren’t getting the information that we need about our environment to feel safe. Too loud and we can’t process anything else because our brains are overwhelmed. We may even feel pain from sensory inputs that are too loud.

Since we have 9 channels on which we take in information about the world around us, there are 9 different ideal volumes at which we function at our best. Think of your sensory systems as a sound board.

To function well, we each have different ideal levels for each of these switches.

Sensory Needs

Having sensory input is a biological requirement. If one or two of the sensory channels goes quiet, we can adapt and manage pretty well. We know of people who have lived very happy lives while both deaf and blind. People missing one or two sensory inputs need support because those inputs are important to survival, but we can adapt.

However, if the sensory organ is functional and not receiving sufficient input, it can create feelings of unrest, dysregulation, and discomfort. Without even realizing it, those with unmet sensory needs will seek out those inputs to feel back in balance.

Increased sensory needs happen for 2 reasons: the body is less sensitive to the input or the needs for that person are much higher. For a person who is less sensitive, the nerve endings that carry the sensory information require more input to trigger them. Flipping the on switch is harder. And we can think of the people with more sensory needs as having a high sensory metabolism. They just need more than many other people.

But regardless of the cause, both kinds of high sensory needs people need more input than those people around them. Without it, they feel unwell.

Sensory Sensitivities

On the other side, sensory overwhelm is a painful experience. Like our ears hurt when sounds are too loud, skin can hurt when something painful touches it. Smells can cause nausea. Like sensory needs, sensory sensitivities are not just preferences and desires, they are biological needs that have to be addressed.

Being sensitive to sensory input may mean that the nerve endings carrying that information are triggered by very small stimuli, or it may mean that the processing center in the brain gets overwhelmed by the information it receives. Either way, the only resolution is to cut back on the input.

So how do we increase or decrease input from the world around us? We'll look at that in part 2.