Making Sense of Sensory Processing: The Different Classifications Explained

Have you ever noticed how sometimes you crave big, bold experiences—blasting your favourite music, enjoying spicy food, or needing constant movement—while at other times, the smallest thing, like a scratchy clothing tag or a buzzing light, feels completely unbearable?

That’s the fascinating world of sensory processing at play.

We all process sensory input every single day. It’s how we take in, organise, and respond to the world around us—through sight, sound, smell, touch, taste, movement, and even internal signals like hunger or heart rate.

When our brain is able to sort and filter this input effectively, we can stay regulated and focused. But when the brain struggles to integrate that information, it can feel too strong, too weak, or just plain confusing. That’s when sensory processing differences—or Sensory Processing Disorder (SPD)—come into play. And the impact can range from mild annoyance to actual physical pain.

Dunn’s Four Patterns of Sensory Processing

One helpful way to understand SPD is through Dunn’s Model of Sensory Processing. It looks at two things:

Your threshold (how sensitive your brain is to sensory input)
Your response (whether you tend to be more passive or active)

Together, these create four patterns:

Low Registration – A high threshold with a passive response. These individuals often don’t notice sensory input and may seem uninterested, under-reactive, or hard to engage.
Sensory Seeking – A high threshold with an active response. These are the people who crave stimulation—rocking, tapping, fiddling, or chasing big sensory experiences like rollercoasters, loud music, or strong flavours.
Sensory Sensitivity – A low threshold with a passive response. The nervous system picks up on everything, which can feel overwhelming. Instead of changing the environment, these individuals often just endure it—leading to distraction, discomfort, and exhaustion.
Sensory Avoiding – A low threshold with an active response. These individuals are quick to notice sensory input and actively work to avoid it. They might skip crowded places, choose soft clothing, or keep their environments quiet and predictable.

Miller’s Classification of SPD

Another way to look at SPD is through Miller’s classification, which describes three main types:

Sensory Modulation Disorder (SMD) – The most common, affecting how people regulate input (hypersensitive, hyposensitive, or sensory seeking). It often interferes with daily life activities like eating, sleeping, or socialising.
Sensory-Based Motor Disorder (SBMD) – This impacts movement and coordination. It includes dyspraxia (trouble planning movements) and postural disorder (poor balance or low muscle tone). It may look like clumsiness, difficulty with sports, or challenges with fine motor skills.
Sensory Discrimination Disorder (SDD) – Difficulty distinguishing between sensory inputs, such as telling where a sound is coming from or mixing up textures. This can lead to awkward motor skills or trouble staying attentive.

Why This Matters

So many adults think their reactions are just quirks—“I’m weird,” “I’m too sensitive,” or “That’s just me.” But the truth is, these responses are often rooted in how your brain is wired to take in and process the world.

And here’s the good news: once you have the language and understanding, you can begin to notice your patterns and put supportive strategies in place.

Final Thoughts

If you’ve been reading this and thinking, “That sounds like me,” you are not alone. Awareness is the first step. From there, you can start to explore strategies, supports, and environments that help you feel more comfortable and in control.

I’d love to hear from you—do you see yourself in any of these patterns? Drop a comment below and share your story. Your voice might help someone else feel less alone.

And if you’d like a simple, practical way to begin, I’ve created a free Sensory Overload Checklist. It’s a guide to help you recognise the signs that show up when you’re nearing your sensory limit. You can grab it by clicking on the link below.

Remember—you're not too much, and you’re certainly not alone.

Free Sensory Overload Checklist