It is likely that, as an elementary schooler, you learned about the “five senses” of the body. Perhaps you did simple experiments exploring your body’s receptors for touch, taste, hearing, smell, and sight. Then, when you learned about sensory processing challenges, your child’s OT may have filled you in about some of the more “hidden” senses, such as your ability to process information about where your body is in space and the force and direction of your muscle movements, also called the vestibular and proprioceptive senses. Understanding how information is received and interpreted by all these senses can be very helpful in understanding your child’s—and your own!—ability to function in the multi-sensory environments of our day-to-day lives. But, it isn’t the whole picture.
Within the last decade there has been an increasing amount of scientific interest in the relatively unknown interoceptive (sometimes spelled enteroceptive) sense. Interoception is unique in that it allows us to understand not what is happening in the world around us, but what is going on inside our own bodies. Interoception is how we know that we are hungry, that we need to use the bathroom, that the movie UP made us feel sad, or that we are feeling sick and under the weather today. It appears to be related not only to specific receptors within our body’s organs, such as stretch receptors that can judge how much the stomach has expanded after eating a tasty meal, but also with a certain area of our brain called the insula which is responsible for interpreting these signals. Every person seems to fall on a continuum of ability to accurately judge and understand interoceptive signals, from the most seasoned meditation expert who can not only judge the rate of his heartbeat but actually work to control it, to the potty training toddler who is surprised to find that his diaper is suddenly wet.
Although the research helping to define and categorize these internal signals is new, we can tell by the way we talk about our feelings that humans are aware of internal state changes and the way they are tied to our emotions. When we are nervous before a performance we might speak of “butterflies in our stomach”; in a new romance, we might notice our “heart skipping a beat”. Trouble making meaningful use of the signals coming from within your body can lead to a variety of difficulties in daily functioning. Some are high-impact but not necessarily surprising, such as the finding that people with low interoceptive awareness may not seek medical treatment right away for conditions such as a heart attack, or are more susceptible to drug and alcohol abuse as they are less aware of the impact these substances have on their body’s functioning. Other findings are more surprising: adults with high interoceptive awareness seem to be better gamblers, as they are more sensitive to “risk conditions.” On the other hand, children with autism spectrum disorders seem to have a higher level of “internal attention” to interoceptive signals that may compete with their ability to attend to and understand their environment. More subtle difficulties making sense of emotions and internal states can lead to trouble feeling empathy, telling stories, and enjoying emotional touch expressions such as hugs and kisses.
It is certain that we will learn more about the complex, interconnected, and little-known systems that underlie our enteroceptive sense in the coming years. It is increasingly an avenue of interest for academic occupational therapists and even for laypeople, as evidenced by a number of upcoming “pop science” books about the topic, such as The Interoceptive Mind: From Homeostasis to Awareness, available in December 2018. In the meantime, professionals in the sensory integration field are working to devise methods to help increase our clients’ awareness of, and ability to respond to, these signals. One big takeaway from the literature? Start small! Practice noticing with your child the sensations from one specific body part at a time: how do my eyes feel today? My hands? My stomach? When your child is able to tell you that his eyelids feel heavy, his head fuzzy, and his feet are moving slow, you can help him move into recognizing that these signals are probably his body’s way of telling him that it’s time to go to bed!