Sensory Processing Disorder 101:
SPD is a brain based condition where the brain does not receive sensory information properly. It is on par with brain damage – meaning there is no cure, no medicine and no surgery to repair it. There are two very important to things to know about when trying to understand SPD. First, it is important to know the difference between Seekers and Avoiders, and second, it is vital that you understand how many senses humans have and what their impact is on the body.
Kids with SPD are either SEEKERS (they crave sensory input) also referred to as UNDER – responsive, or they are AVOIDERS (they are overwhelmed by sensory input) often referred to as OVER-responsive and most are a combination. They make seek some sensory input and avoid others. This inconsistency in behaviour can be confusing.
There are the 5 senses that people commonly know: sight, touch, taste, smell, hearing and there are two other important (but lesser known) senses – the Vestibular & Proprioception.
The Vestibular sense is responsible for giving the brain feedback about movement and information about where your body is in space. Is it upside down, leaning, sitting etc? Our balance relies on the Vestibular system.
The Proprioceptive system is responsible for giving the brain information about WHERE the limbs are in conjunction to the body. Proprioceptive info is helpful in coordination and aids the body for things like cart wheels and organizing movements.
There are literally dozens of senses that can be problematic for SPD kids. Many people do not realize that almost every behaviour or action is controlled by a sensory system. Here are a few more that you may not have heard about:
Kenesthesia – The sense of muscular movement. It is the sense which helps us detect weight, body position, or the relationship between movements in our body parts such as joints, muscles and tendons. Kinesthesia, Proprioception and Vestibular all work together.
Thermoception – The sense of hot and cold. Allows the body to properly sense temperature.
Interoception – Internal input. The ability to sense information that occurs within the body. Things like the need to eliminate, hunger cues, pain cues and even emotions.
Chronoception – The sense of the passage of time.
I personally tell people that anything that has the word “sense” in it is affected by SPD. So, sense of force, sense of direction, number sense, common sense, sense of speed, sense of pressure and on and on.
As you can see, there are so MANY senses (other than the 5 people commonly know about) and factors like seeking, avoiding, and combined, that there are no hard fast rules for what SPD “looks” like.
Here is a real life example: Someone who is over-responsive to audio information may find themselves overwhelmed by everyday audio information. If you are in the kitchen preparing their breakfast you are creating LOTS of sounds to an over-responsive (avoider) person. The sound of the microwave humming (and beeping), the faucet running, you walking about in the kitchen, dishes being clinked together, bacon sizzling in a pan, maybe the phone ringing, toast popping up in the toaster, forks clanging together etc. To a neuro-typical person these noises are easily tolerated. To an over-responsive person this cacophony of sounds might be similar to what it sounds like to be in the kitchen of a very busy restaurant on a Friday night! The chaos can trigger a whole host of undesirable behaviours and most people struggle to understand what set them off.
Further complicating the issue is that each day can be different. A child who slept well and who is in a familiar place with people that he trusts may find it tolerable. That same child could easily find themselves, the very next day, irritated by lack of sleep (a common SPD issue), stomach pains from being constipated (another common problem) and perhaps they have just been told that there is no bacon left. That child is now straining to cope with these issues and even the smallest thing (like the TV being turned on) could be the thing that sends them over the edge and causes them to have a meltdown.
Many parents in that situation might assume that their child was lashing out because there was no more bacon. Lots of SPD kids also have food rigidity and this could easily be a natural conclusion. Also one that many outsiders might draw when they are in situations where your child is being difficult.
Hopefully this helps you better understand Sensory Processing Disorder, the senses that guide our bodies and the impact they have on children when they are seekers and/or avoiders.