more hyperactive. It was my assumption that he was using his muscles and joints to stay "grounded" and feel safe, but because he had no sense of where he was in space, the movement made him more disoriented as time went on. Sitting with his device allowed him to orient to that one point in space, the screen, but did not allow him the opportunity to "reset" and orient to his surroundings.

For both Steve and Gerald, their vestibular system wasn't giving them information that allows the accurate development of a brain process all of us use every day, all day, called "feedforward". Not only does the vestibular system fact-check the physical experiences we are having, it also helps us predict that will happen in the physical world. In their 2005 summary of the functions of the vestibular system, researchers Brian Day and Richard Fitzpatrick state that the vestibular system "provides our brains with a deep and special understanding of how the force of gravity moves things, from the fall of our body as we lift our foot to take a step, to the fall of a ball during a game of cricket. In all of these situations, the brain predicts the trajectory of fall with startling accuracy." That is feedforward. We learn how things move when affected by gravity, because we first understand how gravity affects our own bodies; from the increased muscle action needed to control our head balanced on top of our neck, to the feel of horizontal movement when we're being carried versus vertical movement as we are set down, to the coordination of our eyes and ears around our center as we rotate left and right. All these sensations must match up accurately and consistently, to build a database of vestibular sensory experiences that allows us to translate our experiences into guesses about how gravity affects other people and things.

Without the ability to build a feedforward paradigm that allows a child to begin to predict physical interactions, the world remains an unpredictable and unsettling place. A child doesn't come to learn how much force it takes to hug, versus tackle, someone. Or when

an object will fall, versus when it is stable on a surface. Or when an object moving in a particular direction, such as a car, will continue to move in that direction. These predictions about what is likely to happen play a big role in the development of emotional stability, the ability to learn new information, and the development of connections with others through play and physical contact (e.g. learning the force it takes to roll a ball to another person, or building a block tower that will stay put). The vestibular system is what allows for the development of feedforward, and feedforward allows a child to correctly predict actions and consequences, giving them emotional and physical stability in the world.

Having fun is the work of childhood. And it can happen more easily and more often if a child has a functioning vestibular system that makes them feel secure, effective and successful. •

ABOUT THE AUTHOR:

Robin Abbott, MS, OTR/L is an occupational therapist with 12 years' experience working with families and children with autism, ADHD, SPD and Down Syndrome. Her practice is a theoretically-based, structured framework of auditory and vestibular activities to promote better sensory integration. She is currently works as a Rehab Liaison in Davenport, IA. She can be reached through her website, rabbottwriter.com

References

1. Dora E. Angelaki and Kathleen E. Cullen. "Vestibular System: The Many Facets of a Multimodal Sense." Annu. Rev. Neurosci. 31 (2008): 125-150.
2. Brian L. Day and Richard C. Fitzpatrick. "The Vestibular System." Current Biology 15, no. 15 (2005): R583-R586.
3. Antoine, Michelle W., Sarath Vijayakumar, Nicholas McKeehan, Sherri M. Jones, and Jean M. Hébert. "The severity of vestibular dysfunction in deafness as a determinant of comorbid hyperactivity or anxiety." Journal of Neuroscience 37, no. 20 (2017): 5144-5154.

VESTIBULARLY-FOCUSED THERAPY : RULES OF THUMB

So, if the vestibular system is not functioning appropriately for some children with autism, what can be done about it? Your child may already be getting some vestibular-focused therapy, especially if they receive outpatient, clinical occupational therapy, as this type of treatment tends to be the purview of OT. But there are some rules of thumb that my time in the clinic with children has proven to be more often true than not.

1. Vestibular treatment should begin by NOT actively asking the child for a response. Imagine if you had not been able to see for a long period of time, and suddenly your sight was restored. Wouldn't you spend some time just looking around, feeling what it is to see, before you start interacting with your world using vision? When a child feels a vestibular sensation strong enough to register it, after a long time NOT feeling those sensations, they need a moment to get used to it. Also, when we ask for them to participate, such as by keeping their balance while playing a game, they will most likely use their "back-up systems," vison or proprioception, to complete the task, instead of learning to use these new vestibular sensations. Passive movement, on a swing or rotary board is almost always where I begin. 50 April 2022 • EP Magazine | epmagazine.com
2. There is a large part of bodily coordination that is built around our understanding of what direction "straight down" is, especially straight through the center of our bodies. This sensation is highly dependent on a part of our vestibular system called the saccule. The saccule is noticeably activated when you feel "heavier" as an elevator suddenly moves to take you up. So, any up-and-down movement that activates this sensation should be part of therapy. Passive bouncing on a big ball and large swinging arcs are my go-to's.
3. Once I'm sure the child is sensing vestibular input, then it's time to put it into practice with balance skills and games. Some of these activities should be seated or stationary, like standing on a stepstool without losing balance, or sitting on the floor in cross-legged to play a quiet game, without using one's arms to support oneself. Being in control while still is a challenge for those children who use their proprioception excessively, and physical control when on the move is a challenge for those children who anchor themselves visually. I know I'm making good progress with a child and helping their vestibular sense when they can do a task that was difficult or uncomfortable for them, and have fun doing it.