Why can’t little Bobby sit still in his chair? Why is Mark constantly in motion? Why is Betty so slow when she copies from the blackboard? Why does John constantly trip over his own feet and bump into everything? To answer these questions, we need to understand the sensory system.
We are all familiar with our five senses, taste, touch smell, hearing and sight. However there are two very important senses that give our brains sensory information that is necessary for us to feel calm and regulated and to perform intentional and coordinated actions. They are the proprioceptive sense and the vestibular sense. These two sensory systems play a significant role in our awareness of the world and in our ability to understand and learn (Hannaford, Pg 38).
Proprioception
In all our tendons and muscles are tiny little receptors called proprioceptors. The word comes from the Latin proprius meaning “one’s own.” Every time we pull or stretch or compress our joints, every time we contract our muscles, our proprioceptors send messages to our brains, telling our brains what part of our body has moved and how much force has been exerted. Our proprioceptors continually give our brains information as to what is going on in our bodies, giving us a sense of our bodies from the inside. The proprioceptors in our fingers tell our brains what letter our fingers are making, so that we don’t have to look at our fingers to see what we are writing, we can look at the blackboard as we write, and keep up with the rest of the class.
Vestibular
Our vestibular sensory system tells us if our head or our body is moving. For example, if we begin to walk across a room, our vestibular system tells our brains our head is moving through space (because it is sitting on top of our body). Our proprioceptors from our legs also send messages to our brains that our legs are moving, thus our brain “concludes” that our whole body is in motion. If we just turn our heads because we hear our name being called, our vestibular system tells our brains that our head is in motion, but since our brains are not getting information from our legs, our brain “concludes” that only our head, and not our whole body is in motion. If we watch someone else moving across the room, our vestibular system tells our brain that we aren’t moving, that we are still. The vestibular system is housed in the semi-circular canals in the inner ear. The same nerve that brings what we hear to the brain also brings our sense of movement.
Our vestibular system is so important it is the first sensory system to fully develop (five months after conception). It is the sensory system considered to have the most important influence on our everyday functioning. The vestibular system is the unifying system that directly influences nearly everything we do. It even impacts how awake and alert we are (Hannaford, Pg 38).
There is an area in our brainstem known as the Reticular Activating System (RAS). The job of RAS is to “wake us up,” getting us ready to take in and respond to our surroundings, and to learn. The vestibular system sends sensory information directly to the RAS. Sometimes, the reason why Bobby can’t sit still in his chair is that he is trying to keep himself awake and alert through providing his RAS with vestibular input (Ayers, Pg 74).
One of the jobs of the proprioceptive sensory system is to help modulate the vestibular system. Muscle and joint sensations enable the brain to use vestibular sensory input more efficiently. Therapists will often recommend to parents and teachers to have their child do, “heavy work;” i.e. push the wall, carry heavy items, jump up and down, rough house play with dad; these heavy work activities contract a lot of muscles and compress many joints in the body. This helps the brain inhibit some of the excessive vestibular activity that is problematic (Ayers, Pg 75).
Body Scheme
In order to create any successful movement, whether writing letters legibly, or walking to the front of the class without bumping into a desk, or another classmate, sensory input from the body must be organized into a clear “picture” or map of the body. The brain must have an accurate internal sensory map if it wants to accurately move the body. This internal sensory map is often referred to as body scheme (Ayers, Pg 98).
Proprioceptive input from our muscles and joints contributes to our body scheme. Without this information we would not know where the parts of our body are or how they are moving. As we move our bodies, proprioception updates our body scheme so that our brains can plan the next movement correctly, and contract the muscles at just the right time so we are successful. Children who have challenges processing and integrating proprioceptive information have a vague or hazy proprioceptive sense and their brains don’t have an accurate body scheme. They often have to overly rely on vision to know exactly where their fingers, hands, legs and feet are. These are the children who take longer to copy from the blackboard then their classmates. They have difficulty sensing how much muscle effort they need to use and so they push too hard, they don’t try hard enough, and they break things. They stumble over their own feet and bump into everything (Ayers, Pg 98).
Movement information from our vestibular sense also adds to our body scheme. Vestibular information helps orient our bodies to the space around us. The vestibular system sends information down the spinal cord to modulate information from our muscles and joints. If the vestibular system is not working well, then the other senses are less efficient. Impulses from the vestibular system also travel to the muscles, keeping them firm and ready to respond, this is called muscle tone. Many children who have challenges processing and integrating vestibular information also have low muscle tone. This reduces the amount of proprioceptive feedback the muscles send to the nervous system. As we can see, the proprioceptive and vestibular systems have a profound effect on each other and how the body functions as a whole (Ayers, Pg 99).
How We Can Help
Another way we can help children who have challenges processing and integrating proprioceptive and vestibular information is through how we interact with them. Sensation is “food” to the nervous system. Providing our children who have challenges processing and integrating proprioceptive and vestibular sensory input throughout the course of their day will help “feed” their nervous systems what they need. Simply, vestibular is “movement” and proprioception is “heavy work.” If these can be incorporated seamlessly into the child’s everyday routine, over time, it will help organize his nervous system. Can you do ten or twenty jumps in the morning while he is getting dressed? Can you do push-ups or push a wall? Can you do simple yoga postures as in downward facing dog? Before he gets out of bed can you arm wrestle? Can you begin to look at your child’s daily routine, and create simple games that allow his body to move and his muscles to work?
Our emotions also play a large role in how we interact with ourselves and with others. CAT scans show that children process information through their emotions first, and information that is most emotionally relevant to them, is what they process first (Hannaford, Pg 62). So; if you are used to getting into a battle of wills with your child over their handwriting, or having to sit still, what they are learning is how to fight authority figures. I always tell parents, when I am working with any child, one of my goals is to always keep their emotions and their thinking (cognition) in alignment. So, whatever they are interested in is what I am interested in. No matter how long or how short of a time. The goal is to keep their emotions and cognition in alignment. When I interact with them, and respond to their interests with my genuine emotion, what happens is they naturally pay more attention to whatever they are interested in for a little longer. This is a gentle and efficient way to help them develop a longer attention span. Over time, this will also help them develop a more calm and tempered approach to the world.
References:
Ayers, A. Jean, Ph.D: “Sensory Integration and the Child;” 1979: Western Psychological Services, Los Angeles, CA
Hannaford, Carla, Ph.D.: “Smart Moves: Why Learning Is Not All In Your Head;” 2005: great River Books, Salt Lake City Utah
