When I went on Sensory Integration training (admittedly about ten years ago) we were taught that there are seven senses: all the ones you usually think of (taste, touch, sight, smell, hearing) plus proprioception and the vestibular system.
Proprioception is the sense of knowing where your body is in space and is stimulated by things like deep pressure, heavy work and vibration.
The vestibular system is in your inner ear and is the sense that helps you battle gravity. It is stimulated by movement, especially spinning or being upside down, and is the sense that causes travel sickness. If anybody has experienced Labyrinthitis they will have experienced their vestibular system on overdrive! Grizzly had it so badly that he literally didn’t know whether he was the right way up or not and couldn’t get out bed for several weeks or even move his head.
I think about Sensory Integration (SI) quite a lot when it comes to Little Bear and I’ve previously written about it a little in Too fast, too hard, too loud. The basic premise of SI is that everybody has a sensory system and we are integrating sensory stimulation all of the time. Everybody’s system is different and what we can cope with/ what we need in terms of sensory stimulation in order to be comfortable in our bodies will differ too. Little Bear certainly seeks proprioceptive and vestibular input which has led to us having a free standing pull up bar in the playroom so he can climb and hang as he needs, instead of seeking similar input in a more dangerous fashion (like clipping his belt loop to the bed and hanging from there. Full marks for ingenuity but a little too dangerous for my liking).
However, a couple of articles have caught my eye recently which have suggested my SI knowledge is a bit out of date. Current thinking is that there are in fact 8 senses: all the ones I mentioned plus something called Interoception. I have done some digging to figure out what it is and why it might be important for our children and thought it may be useful to share.
Interoception is a bit like proprioception but from the inside. It is the sense of knowing how things are within our bodies. It includes things like being aware of our heart beat and whether it has sped up or slowed down; being aware of our digestive system – are we hungry/are we full/do we feel sick; is our temperature ok – are we too cold or too hot; awareness of blood sugar – are we getting shaky and a bit low on fuel; awareness of our bowel and bladder – are they full/ do they need emptying; do we have pain anywhere.
I’m imagining it like there is a telephone system between our internal organs and our brain. The lines of communication need to be kept open so that if our heart is beating faster, it can “ring” the brain which can then take measures either to ignore that or suggest for you to sit down and rest for a bit. Or you might have a full bladder. The bladder would call and tell the brain to make you aware you needed a wee and you would go to the toilet. It’s all good and very effective when working properly but there are lots of things that can get in the way.
Studies of infants have suggested that interoception develops very early, perhaps in the first few months of life and might be stimulated by things such as their parent stroking their cheek or rubbing their back – which are pleasant sensations that might ease internal states. One study showed that being stroked on the face led to a decrease in heart rate in 9 month olds. I read something else which stated that infants “associate interoceptive signals of warmth and satiety with their caregiver’s face, which in turn drives attachment behaviour”.
From the limited evidence, you can see that a child who has been neglected (hasn’t received physical comfort) or who has had multiple caregivers (seen many carers faces), might not develop typical interoceptive skills. There is already evidence to say that children who have suffered physical abuse grow up to have altered pain sensations. One article I read suggested that investigating the impact of adverse childhood experiences on interoception is a big area which requires loads more research.
Even if we don’t fully understand all the reasons why a child may end up with a faulty interoception system, we do know that they can and that they may be under-responsive, over-responsive or seeking of interoceptive input. Being over-reactive to bodily signals such as heart rate, butterflies and muscle tension has been associated with anxiety and depression. I suppose that is the equivalent in my analogy of the brain being phoned constantly for every internal twinge or tickle instead of just for the big ones.
Being seeking or under-responsive to feelings of a full tummy has been linked to eating disorders. In this example the brain isn’t getting the call when the tummy is full or the brain starts to panic when there aren’t calls so stimulates the body to continue eating. Something about the feeling of fullness is desirable. I think the converse could also happen – being empty being the more desirable feeling.
If children struggle with interoception, they can find it difficult to know whether it is something inside or outside of them that is causing discomfort, leading to dysregulation or an unusual response. I think hunger is a really good example as Little Bear definitely struggles to identify when he’s hungry (hangry!) and will tend to get irritable and aggressive with anything and everything rather than identifying his tummy is empty and that he needs to eat.
Some researchers think that interoception could underpin many psychopathologies and could be a lot more crucial than we yet realise. One thing they do agree on is that being able to recognise and respond to your internal states (interoceptive feedback) is a crucial skill for recognising your own emotions, learning and good decision-making. Poor interoception tends to be linked to risk-taking behaviours such as drug-taking, promiscuity and alcohol abuse in later life. Could this be because these things tend to heighten sensation, giving the brain the feedback it needs but doesn’t usually get?
As emotions such as anger, nervousness, and excitement have a physical impact on the body, as well a neurological one, we can see how interoception also has an involvement with our emotional development. In fact interoception is crucial in helping us to identify which emotions we are feeling from the signals our bodies are giving us.
It turns out that interoception is a much more complex and wide-ranging sense than you would initially think.
So what about Little Bear? What I have learned that is of use to him?
Well, according to SPD Star “it’s only when all of the other senses are regulated and in check that our body is quiet enough to listen to what those internal signals are telling our brain”. In other words, most children who experience SI challenges are likely to experience some interoceptive differences and they won’t be resolved until their other sensory needs are being met. Let’s hope that hanging bar is doing its job then.
I have identified that when it comes to the interoceptive sense, Little Bear is under-reactive. I have already mentioned that he would neglect to eat without adult support but perhaps the biggest thing I’ve learned is that he is probably under-reactive in the bowel/bladder department too. I have talked about his Continence Issues previously but this information shines a new light on them. It seems very likely that the phone line between Little Bear’s bowel/ bladder and brain is a bit faulty. When the bowel/bladder start to fill up, the message does not immediately get passed to his brain. It is only when they are full to capacity and the red warning light should be going off that Little Bear’s brain gets the signal to tell him to go to the loo. By that stage he often needs to run and sometimes he inevitably doesn’t make it. The theory certainly fits with the behaviour we observe.
I like this as a way of explaining why he’s not consistently dry, it makes sense. As with most aspects of SI it also means there is hope and that with the right approach he should be able to make progress.
I have found it more difficult to find specific advice about how exactly to work on interoception, other than to speak to an OT or get a sensory diet written. However, what I have gleaned is that you basically want to get the brain more tuned into the signals from the organs/ muscles and Mindfulness is mentioned quite a bit in the literature. I guess that makes sense – quietening everything down so that you can hear the internal whispers that you would otherwise miss. Once you are more tuned into those signals, your brain should get better at listening out for them.
Some of the things we already do at home seem to be appropriate for improving this sense. Things like when Little Bear is hungry, I will draw his attention to the rumbling sounds from his tummy and explain what they mean. Sometimes he will say he has tummy ache and I’ll know from the coincident hyperactivity that he needs the toilet. Since reading about interoception I am getting more conscious of not just herding him to the loo but trying to encourage him to feel that tummy ache and identifying it as the feeling of needing the toilet and explaining that when you feel that sensation, you know you need the loo. This sort of cause and effect doesn’t always come naturally to our children anyway and sometimes they do need us to state things that seem obvious to us (it isn’t obvious to them otherwise they would be able to act on the sensations).
Apparently regularly prompting a child to go to the loo helps them to get used to the sensation of an empty bladder and to experience the contrast with a full bladder which should help to develop their interoception over time. Using technology such as vibrating watches is a helpful way of keeping on top of their interoceptive challenges a bit more independently, as well as teaching them strategies such as going to the toilet during every break whether they think they need it or not.
As with most things adoption related, this isn’t a quick fix. It takes time and getting other sensory needs under control first.
I can see improvements in Little Bear’s interoception system though. He was certainly under-responsive to pain when we first met him and though he still has a high pain threshold (a few more than average phone calls from the injured area to the brain before a response happens) he does now respond to knocks and bumps in a much more typical way. He will cry and come for a rub where previously he could have banged his head on a solid object and not even broken step or let out a yelp. The toileting and hunger issues have improved too, but in a stepwise fashion, where we still have some steps to go.
Interestingly, while being hyper-aware of your own heart rate can go hand in hand with anxiety, some children enjoy the sensation of a heavily beating heart and actively seek this – driving them to exercise – and consequently they become very fit. I’m not sure if this applies to Little Bear but I’m not sure that it doesn’t either as he certainly likes running about/ bouncing/ hanging etc. and is developing into an impressive sportsman.
As with most differences, a differently developed interoception system brings its challenges but also its unexpected silver linings.
*If you want to know more about interoception, this is a particularly comprehensive article:
**This blog is based on my own reading. If you think I’ve missed something or not quite explained something properly please let me know.