Interoception – the hidden sense.

“Intero what…?!” That’s what people often say when they hear the word interoception. Most people have never heard of it. But it’s one of our 8 senses, the one I feel is known about the least. The five everyone knows about are vision, hearing, taste, smell and touch, but the other three less known senses are proprioception (how we know where our body is in space), vestibular (helps us balance, know which direction we’re moving in) and interoception. I’m going to talk about interoception and consider it in relation to clients who have had an acquired brain injury.

Interoception is how we perceive internal sensations. For example, this sense helps us to recognise if we are hungry, thirsty, need the toilet, are unwell (these are considered our homeostatic emotions) and how we are feeling emotionally. For example, when we are happy, angry, excited (these are affective emotions).

We have receptors everywhere inside our body which help us identify these different internal states. For some people, they have no difficulty with their interoceptive awareness whereas others might struggle to notice the internal cues at all or may feel sensations without knowing which emotion they’re connected to. Some individuals experience feelings intensely. Some people may never feel full even if they have eaten a substantial amount of food or always feel hungry, others may not feel thirsty until the end of the day and some might not know they need the toilet until they are desperate.

Body signals and emotions

Thinking about our affective emotions, our body gives us clues for how we are feeling, for example, if worried or anxious our heart beats faster and our muscles tighten. Or if we are happy, our muscles may be relaxed, and our heart may beat at its normal rate. But if there are differences with knowing how your body is feeling then it can affect recognising these different emotional states or confusing them. Having butterflies in your stomach because of feeling nervous could be mistaken for being unwell. To make it more complicated, some emotions may be recognised with ease whereas others could be harder to identify within the same individual, depending on which receptors, and which parts of the body are involved.

Interoception in OT practice

Learning about interoception as an OT has definitely helped me as a parent too. I attended the Kelly Mahler interoception curriculum course in person in 2024 which was really valuable for my work and helping with raising my own children. I try not to tell them they are hungry or sad but say what I’m observing to try and help them link their body signals to their emotions and develop their interoceptive awareness.

Interoception is talked about a lot with regards to certain neurodiverse diagnoses, including autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD), where there are often sensory differences experienced, which can affect how the individual participates in their everyday life. I work with clients who are neurodiverse and I also work with children and adults who have acquired brain injuries, and sensory differences can be a common change following this, including interoception differences.

Assessment and intervention after brain injury

When working with a client with a brain injury and interoception is flagged as a possible difficulty, I would assess their interoceptive awareness to gain a baseline and determine whether it does seem to be a difference with interoception or more of a cognitive and/or physical issue. Gaining this information would be through direct communication with the client and with people who know them well, for example family or support staff.

If it does seem to be an interoceptive awareness difficulty, treatment can try and increase their awareness of their body to help them link the sensations to the feelings. In basic terms, it’s body mindfulness focusing on one body part and expanding this to more body parts depending on the individual. Kelly Mahler’s Interoception Curriculum can be adapted and used as needed for different clients which makes it very accessible.

A brain injury could be in an area that directly has an impact on a homeostatic emotion, for example temperature regulation is controlled in the hypothalamus so if this area is damaged, the individual will very likely have temperature regulation difficulties. The extent of the damage will determine if the difficulty will improve through neuroplasticity, and this will help form the treatment recommendations – whether a compensatory approach, rehabilitation approach or a mixture of both. Increasing interoceptive awareness can take a long time and it needs to have a regular and consistent approach to increase the chances of it helping. Modelling your own behaviour is also a big part of it, for instance saying my stomach is rumbling and I have no energy, so I must be hungry.

Having knowledge of this hidden sense is invaluable, especially for individuals who have interoceptive awareness differences and people that are close to them, as it helps to understand why certain behaviours may be happening and the reason for it.

Learning about sensory integration and interoception has helped me as an OT, parent and reflecting on my own sensory profile and making sense of it. I’ve always been quite an emotional person and I feel things strongly. I would struggle to hide how I’m feeling, which now I am an adult, I see as a positive! We are all different, including our level of interoceptive awareness, the hidden sense.