Making Sense of the Senses – Part 2 – The Secret Agents of Interoception and Proprioception

by Nanny Aut

A quick ‘health’ warning – this post turned out a lot longer than I first expected, so you may want to read it in sections, rather than trying to complete the marathon in one go. These posts are intended for education and for future reference, rather than ‘sound bites’ and can be heavy on the detail. An autistic overly detailed oriented? Never!

In the last post, the well-known senses – sight, sound, smell, taste and touch – were discussed and how they are affected by the spiky sensory profile that most autistics have. In this post, we focus on the less well-known senses grouped under Interoception and Proprioception. Even though they are less well known, these groups of senses arguably have the greatest effect on the autistic nervous system. These senses often cause challenges that many are unaware of, because they do not realise these senses exist or how important their effective feedback is to our well-being.

Interoception refers to the group of senses that relay information about the internal state of our body in order to enable us to maintain the body in the best condition. These senses tell us when we need to eat, drink, go to the toilet, rest, exercise, warm up, cool down. They tell us about our emotional state, provide feedback on whether muscles are tensed or relaxed, and even tell us about the barometric pressure outside – our weather sense.

Proprioception refers to the group of senses that relay information about the position and movement of our body, both with the body itself and in relation to everything around us. These senses tell us whether we are upright, spinning, going slow, moving fast, where our limbs are in relation to each other. They tell us whether we are on a secure surface, where we are in relation to objects around us, what direction we are moving in. They tell us about personal space and whether someone is within our boundary, and they tell us whether we are trapped or free to escape.

When these senses are too high, we can become over-responsive – for instance, getting severe migraines before a thunderstorm or becoming intensely anxious in an enclosed space. The slightest input triggers can trigger an alarm and can cause Dino brain to react in response to a potential threat.

When these senses are too low, the signals warning of an issue, such as hunger or thirst, arrive unlabelled. The brain knows that something is wrong but has no idea what and so does not trigger an action to deal with the signal. Instead, it puts the body on alert increasing our anxiety and the intensity of our protective response. The brain does pick up that signals are too low, and where it can, it tries to increase feedback by encouraging stimming activities.

This post explores these groups of senses in greater detail and looks at ways we can compensate or accommodate for the spiky profile.

Interoception

This is our internal set of senses. There is a huge array, including ones that feed back about heart rate and blood pressure. This post is going to focus on the ones that carry the most effect for many autistics.

Bodily Functions – Input and Output

For many autistics, we have low to zero sense of hunger or thirst or are able to sense when we need to go to the toilet. This means we have to find other ways to either identify these signals or build a routine that compensates for the lack of signal.

If we experience a sudden surge of anger/anxiety with no obvious cause, these four tend to be the main culprit – particularly hunger and thirst.

Hunger – When we are hungry, we often also get an ‘Energy Low’ signal – so we experience a craving for sugar/fats – we eat a chocolate bar and the anxiety subsides because the brain thinks the problem has been solved. So, instead of reaching for the sugar, we need to reach for high protein, slow burn, easy digest food. Better still we need to build eating regularly into our routine, with well-planned nutritious meals.

Other signals include feeling disoriented or foggy, struggling to process or feeling dizzy.

This lack of signal means it is critically important not to create any sense of worry or anxiety around food. This anxiety registers eating as an aversive, and because there is no sense of hunger, there is no drive to eat to counter it. Children pressured to eat or try new things can develop serious eating disorders because of this. Even though your child not eating ‘normally’ is understandably a cause for concern, it is important that you keep eating a low-demand, low-pressure activity. Introduce new foods away from eating times as a form of play. Keep it light, keep it fun, keep it exploratory. No rewards, no expectations.

It can also be helpful to allow eating alone. As was said in the previous post, eating in a group can be overwhelming sensory-wise, before you add the taste sensory feedback in. Which again raises anxiety and causes the brain to see eating as a negative or traumatic activity that needs to be avoided.

The counter to feeling hunger is feeling fullness, which also tends to run low. We often confuse the stretch of a distended, overloaded stomach with the feeling of ‘full’. This is especially problematic for stim eaters, who eat or chew to regulate, and who can develop an unhealthy drive to over-eat mistaking the drive to stim for a sense of hunger.

Thirst – This is another problematic low signal. This makes it very easy for us to forget to drink enough fluid during the day. Particularly as most drinks are not very stimmy. We are unlikely to notice we are dehydrated until our lips / throat dry out or we start to become disoriented or foggy. Or our pee becomes hot and highly concentrated.

We can become overly drawn to high sugar drinks or stimulant drinks as our brain confuses the fogginess and disorientation of dehydration for a need for energy or brain stimulation. It is really important to build in a routine for drinking during the day and using executive function boosts such as keeping a bottle of water in the eyeline all the time as a reminder. It is also really important that the taste feedback is pleasant. For many of us, chilled water is significantly more pleasant for us to drink than cold water out of the tap. For some of us, even if we chill it, we still need to flavour it with something we like.

Bladder and bowel – this is something that affects more of us than you would realise. Many autistic adults have become so used to compensating for this through toilet routines, they may not even be aware there is an issue, unless the routine is somehow disrupted, or muscle weakness stops the ability to prevent release when those ‘exit’ muscles come under pressure. We can mistake the sense of a badly distended bladder or heavy pressure on the rectum as the signal for the need to go, whereas, if the signal is actually there, it occurs long before this. Going regularly throughout the day makes sure that the bladder/bowel is not pushed past its limits, even though it can be annoying at times to go, only to produce the barest teaspoon of fluid.

These two senses are also ones that can be easily drowned out by other processing demands – so if we are busy with something or in an overwhelming situation, we may not get any signal at all and just release when the muscles can no longer hold the ‘exits’ shut.

When doing toilet training, it is very important to consider whether interoception is at play. If you ask a child who has no sense of their bladder/bowel being ready to release whether they need to go or not – the answer is always going to be ‘No’ – unless it is too late to reach the toilet. And if there are other aversives to using the bathroom – noise, smell, fear of falling down the loo, fear of falling loo seats etc., then they will just keep holding. Which leads to bladder infections and impacted bowels among other issues. This means it is really important to remove anxiety and negative associations around toileting. It needs to be a safe, matter of fact part of their routine. Notice when they are going in the nappy and start providing access to the potty around this time – some parents find it easier to bring the potty into the living room on a plastic mat or dog pee mat, so the child can sit on the potty and watch their favourite programme, creating positive associations. Do not use rewards. First, it creates anxiety around failure to ‘perform’, as this failure leads to the loss of the reward. Second, it leads to an ongoing expectation – if I pee I will get a reward every single time. And when inevitably you have to stop the reward as it is not sustainable long-term, you have broken the agreement and damaged trust. It is very likely to lead to meltdowns. Third, it establishes the precedent of ignoring discomfort and aversives in exchange for a reward. Whether it is going to the loo in a bathroom that is sensorily challenging or allowing someone to touch you in places that make you feel uncomfortable. Many of us struggle to differentiate between the two, which makes many autistics raised in a reward culture especially vulnerable to abuse.

Thermostat

A lot of autistics have either a highly sensitive thermostat, picking up the slightest change in temperature, or a very poor thermostat which means we struggle to register that we need to regulate our temperature. If the thermostat is high, then it is common for autistics to be dismissed – ‘What are you talking about? It’s not that hot/cold’ which teaches them to ignore and over-ride their signals as ‘not true’. If the thermostat is low, we can overheat or become excessively chilled without realising it. In schools, where classrooms are often too hot in summer, you will see an increase of ‘explosive behaviour’ in autistics with a low thermostat sense. They receive an urgent alarm signal but it is unlabelled. Dino brain knows is that the body is under threat and responds in protective mode. A cooler classroom or ways to regularly cool down make all the difference.

Tiredness

Many autistics struggle with sleep because they do not get the signal to ‘power down’. Instead, when we are over-tired we become highly anxious and alert – the complete opposite to what you need for sleep. It is really important that we do not get to the point of being over-tired in order to avoid this. We need to have rest points / low demand points throughout the day and a regular bedtime routine that signals the brain externally that it is time for sleep. The routine needs to have calming activities involved.

Another barrier to sleep is our ever-protective Dino brain. Dino brain thinks sleep is dangerous because then we are vulnerable to the sabre-tooth tiger he know is just waiting outside the door. Before he is willing to allow us to sleep he needs to know we are safe and protected. There can be numerous ways to do this. Creating an enclosed pace to sleep in, co-sleeping / having parent there until fully asleep, swaddling – tight/compression sheets, weighted blanket (this can cause overheating), compression sleepwear, even sleeping on the floor (see Proprioception – Location below).

Pain

It is very common for autistics to be both hyper-sensitive and hypo-sensitive to pain depending on where the signal is coming from. This means that hair brushing can feel like your scalp being removed and a broken foot is mildly uncomfortable. However, where the signal is low, the brain still receives the unlabelled alarm signal. So, anxiety / anger becomes very apparent even though there is no clear source. The autistic knows they are in distress – they just have no idea why. Once the main four senses of bodily functions have been ruled out, then pain is the next on the list if an autistic suddenly becomes disregulated in an otherwise supportive environment.

Emotions

There is a term alexithymia which means a lack of sense of emotions. This is a genuine issue for some autistics, but for many others, it is not that we can’t sense emotions but that our outward response to emotions is not neurotypical. Or that we are unsure of how to label them because others continuously mis-label them for us –

‘Why are you so angry?’

‘I’m not angry, I am anxious and I don’t know why. Maybe I’m not anxious? Maybe I am angry? They seem really certain about it.’

Or the emotion isn’t ours at all so we have no connection between what has occurred and the emotion we are feeling.  A very common phenomenon amongst autistics is called emotional mirroring. This is where our mirror neurons pick up another person’s emotions and re-create the emotion for us as if it were our own. It is the same response we get when we see someone suck a lemon – we get the same pucker/bitter response even though we are not the ones eating the lemon. If we are not aware that this is happening then it is easy to assume the mirror emotion is our own – even though it makes no sense.

It seems that for many autistics, emotional mirroring is our primary method of reading emotions in others, above reading facial expressions and body language, even above words and tone. It is really important to remember about emotional mirroring when dealing with a stressed autistic, because if you are anxious too, it is only going to amplify their anxiety and speed up the oncoming meltdown.

Many autistics also have the ability to switch off emotions temporarily if they threaten to become overwhelming – this is part of dissociation. It is not that we don’t feel the emotion, it is that it is too big to manage at that point in time, so we postpone until all the other things going on around the emotion are dealt with and we finally have space to feel the emotion fully.

Time

Many autistics have time agnosia – we cannot sense time passing – everything is just past, present and future. A week ago feels the same as a decade ago. Five minutes feels the same as an hour. Tomorrow may as well be a year away. This badly affects executive function as we struggle to guess at how long a task takes. It can also create massive challenge when it comes to transitions. The parent says ‘You have five minutes’ or sets an alarm. When that five minutes up it is a massive shock – we weren’t expecting it. It is far better to manage transitions in terms of completion of the activity. Five more blocks and then we do something else. Finish this round and close up the game. Ten more jumps and then we finish trampolining.

Muscle tension/relaxation

Some autistics struggle with feedback around their muscles, which then affects their motor skills as they cannot fully feel the muscle movements they are trying to replicate. This can lead to clumsiness as well as misjudging the strength or effort we put into something. For instance, we may mean to give a light push and knock someone flat. OT can be very helpful in developing connection here.

Barometric Pressure

A number of autistics have a high sense when it comes to barometric pressure. This means our anxiety can be badly affected by certain weather systems even causing migraines before a thunderstorm for instance. Windy days also have a negative effect with many autistics finding themselves a lot more on edge on those days as strong or gusty winds cause local air pressure to change.

The Vagus Nerve

Much as there was ‘one ring to rule them all’ – the vagus nerve is the Ringmaster of the interoceptive senses. When the vagus nerve is stimulated it helps to over-ride the anxiety signals from unbalanced interoceptive senses. Two quick ways to stimulate the vagus nerve is by chewing or by blowing on the base of the thumbs. Chewing is a very common stim because of this and the brain’s go-to response for a lot of anxiety signals.

Proprioception

While Interoception refers to internal body senses, Proprioception refers to how our body connects to the external environment. Some sources split Proprioception into two – Proprioception and Vestibular, however the medical definition refers to proprioception as the group of senses that sense the position and movement of our body and its movement through space. So I will follow that and include the vestibular senses as part of Proprioception.

The Vestibular Senses

These are all connected to the ear canal and the little tubes that act a little like tiny spirit levels. These tell us if we are upright or tilted at an angle; what angle and in what direction we are tilting; whether we are moving; what direction and speed we are moving; whether we are rotating, either around the vertical axis or the horizontal axis. They directly affect balance and co-ordination.

Where these senses are low you will see sensory seeking and stimming activities to increase the feedback on the low sense or senses. For instance, swinging, spinning, rocking, running, bouncing or hanging upside down. As recent research has shown, for all neurologies, where vestibular senses are under-stimulated then the brain can become sluggish and slow. Engaging in stimming activities increases the feedback and helps the brain become more alert and engaged. Students who are fidgeting by rocking or tilting their seat or moving around the classroom are trying to stimulate their vestibular senses and improve engagement and connection. They aren’t unfocused, quite the opposite. Allowing movement breaks, a space to move and listen, wobble boards / cushions, elastic bands around the chair legs to bounce feet on are all simple ways a teacher can use to enable students to focus and engage and access their learning.

This does not apply to all autistics. Stimming to boost vestibular senses should not be done where vestibular senses are high. Then feedback from these activities will be overwhelming and can even cause nausea. Children with high vestibular senses often experience travel sickness. This can make travelling in a car very challenging sensory-wise. As we get older, however, these senses do dull down and so as an adult we may not be as badly affected by this as when we were children.

Balance

Linked to the vestibular senses is the sense of balance, being aware of your body position in relation to your centre of gravity so that you don’t fall over. Where this is low, there is a feeling of insecurity as if you may fall at any time. You can see it where autistics ‘tripod’ to compensate – leaning elbows on a table or desk, leaning up against walls, using a walking stick or a shopping trolley as a third point of balance. Being able to tripod significantly reduces anxiety. Providing seating that provides surround support, such as bean bags, can also help.

Spatial Awareness

These senses provide feedback on where our body and limbs are not only in relation to each other, but in relation to the environment around us. If these are high, reflexes will be quick, if they are low, reflexes slow down and we are likely to keep bumping into things.  We can improve our sense of spatial awareness by improving our core muscles which increases connectivity to our muscle feedback.

These senses also include a sense of direction – for instance, North, South, East, West, Left or Right. Autistics with a high sense can automatically know which direction they are facing and can navigate exceptionally well. Unfortunately, I am the opposite, my sense of direction is very low – I have the ability to get lost on a one-way street. I have no sense of left or right which means reading maps or following travel directions are very challenging. Satnavs has been a godsend providing visual arrows as well as the spoken direction.

One particular spatial sense is that of personal space. For many autistics this extends in a much larger radius than for neurotypicals. Someone in the same room as an autistic can easily be within the autistic’s personal space bubble. This makes it impossible to read when we invade someone else’s personal space, because for us that boundary was breeched two or three metres ago. Teaching a physical distance, such as an arm’s length will be much more helpful in enabling us to identify and respect the personal space of others.

Location

This is how ‘anchored’ you feel to the ground. If you have a low sense of location, you can feel disconnected and floaty. You can often get the same feeling by drinking a lot of alcohol (do not try this at home – drink responsibly). Only for autistics, when this sense is low, they feel like that all the time. It is uncomfortable and can cause severe anxiety. Activities like going for a walk is extremely challenging as part of your brain is never one hundred percent certain where the ground is. Having something to lean on and tripoding can help by giving something to hold on to but having a heavy backpack deals with the feedback by directly increasing the pressure to the feet. This is also one theory why a large number of autistics ‘toe-walk’ – by reducing the area of the foot, they naturally increase the pressure feedback, in addition, the flex of the curved arch as you walk on your toes also increases feedback.

Other things that improve the sense of location: deep pressure hugs, weighted blankets, sleeping on the floor, body sox, hammocks (if they fold around to give a full body squeeze), compression vests/lycra wear one size too small, bean bag seats. Stimming can be done through ‘heavy work’ – doing weights, push-ups against the wall, carrying couch cushions, body slamming against a crash pad, full body squeezes or deep tissue massage.

While this list is extensive, it is not complete. That would take a full text book. However, these are the key players in our sensory profile. Working out which of these are high and which are low is crucial to understanding our environmental needs. It also enables us to correctly identify which senses need to be boosted and which stims to use to achieve this. As well as which senses need to be reduced and which sensory input needs to be minimised or avoided.

When we do work with our sensory profile, our background anxiety drops way down and our processing capacity increases because the brain is no longer trying to manage it all ‘behind the scenes’ and has much less imbalance to deal with.

When people don’t understand and just apply blanket terms of sensory-seeking or sensory-avoidant and just apply stims or encourage the use of sensory toys because they worked for another autistic child, it can make things worse. We can inadvertently push senses further off balance instead of bringing them closer to the middle.

Learning to balance our sensory profile, is, I would argue, an essential life skill for autistics that promotes mental well-being and reduces the risk of stress-related disease in the longer term. Even learning to do it as late as my fifties, it made a dramatic difference. A lifetime of severe anxiety and cycles of deep depression disappeared and neither has returned in the last five years. If I get the early warning signs of anxiety creeping back in, I do another check. Every time the anxiety has started to return it is because I have become lax in the self-care of profile balancing. Fifty years of not looking after myself is a hard habit to break.

This is what early intervention should be used for, so maintaining sensory balance is learnt and applied as the child develops and becomes second nature by the time they are an adult. OTs who properly understand the sensory profile working with parents to identify and educate, so a full, mutual understanding is developed.

Maybe then, we wouldn’t see the prevalence of ‘bad’ or violent ‘behaviour’ and severe mental health issues in autistic teenagers that we are currently seeing. Maybe then. autistics would then be free to fully function in the way that we were neurologically designed to.

This is why autistic adults are speaking up, why we are pushing for understanding and acceptance, why we are fighting to be heard. So the next generation will have access to the skills we did not.