Sensory Integration Treatment founder Jean Ayres, was one of the first people to articulate the idea that some children’s maladaptive behavior may be a result of a vestibular system that does not function properly. The vestibular system, housed in the inner ear, with myriad neural connections throughout the brain, is our body’s way of understanding our relationship to gravity and movement. As an occupational therapist, I rely upon an understanding of the vestibular system to guide treatment, especially when that child is hampered by excessive anxiety and fear.
The vestibular system has connections to the limbic system, the emotional center of our brain that feels anxiety and fear. If incoming information is potentially threatening, then our emotional circuits get involved to prepare us for a physical response. For a child, undependable vestibular input can sometimes result in unreasonable anxiety and fear. A 2010 study of mice who had experienced genetic manipulation of their vestibular system, found that those mice experienced more anxiety and stress during space-related tests, such as mazes and being hung by the tail, than did mice without alteration to their vestibular function. In essence, tasks that were only challenging to unaltered mice, stimulated anxious behavior in those mice without dependable vestibular input.
Imagine that you move to exit the room you’re in and stop directly on the threshold of the doorway. Think about the planning involved: locating the doorway (which involves being aware of your surroundings and having appropriate ocular-motor skills), estimating the steps remaining to get to the threshold (which can be done visually, based on the speed with which the doorway seems to be approaching), and knowing when you need to slow down to achieve stillness, just when you want to (which can be sensed proprioceptively – using your muscles and joints). As you stop, the muscles involved in halting your forward momentum have to coordinate with the associated muscles to keep you from using too much force to stop, and actually falling backward. These split-second reactions can only be processed and executed accurately by using vestibular information. In fact, it is a unique feature of the vestibular system to have such a quick response time-- the neurons that come from the vestibular centers in the brain are noticeably faster at transmitting their information than other sensorimotor neurons in the body.
For children who might not be receiving or processing vestibular information effectively, the delay in response and coordination may help explain why they use too much force for tasks, attempt to execute impossible motor plans, or have unreasonable anxieties. The vestibular system provides “a unique and complete description of head motion and orientation in three dimensions,” state Day and Fitzpatrick in their 2005 summation of the function of the vestibular system. They mention five capacities for navigating the world informed by vestibular input: “Self” versus “non-self” motion (are we moving, or are things moving around us?), spatial orientation, navigation in space, voluntary movement, and ocular-motor (eye-movement) control. If we consider each of functions separately, we may perceive a link between a child’s anxious behavior and the function that may be impaired. In my years in the clinic, I have encountered examples that illustrate how a child’s behavior can be explained in terms of these vestibular functions. While the link between vestibular function and resulting behavior is theoretical, the resolution of these behaviors after clinical vestibular treatment, led me to the conclusion that a vestibular cause for some anxieties is worth considering.
Self versus Non-self Motion
The vestibular system (made up of the vestibuli in both inner ears and the resulting neural connections with the brain and bodily muscles), in its most basic function, senses whether the body is still, or in motion. This function helps the brain unite the sensations coming from throughout our body, into one cohesive picture. Does the visual image in our eyes change as we move? Does sound rotate around or past our ears as we move? Do we feel the ground beneath our feet or our bottom, change as we move? These incoming sensations coordinate to form a picture that makes sense, because the vestibular system is playing a large role in orchestrating what our brains expect. When all this goes as expected, we feel secure and safe.
However, if body sensations are not coordinated with what the vestibular system feels, the disorientation can be disconcerting. I liken this to the common experience of pulling into a parking space at the moment the car next to you decides to pull out. Because your sensory systems do not agree (your eyes sense movement and your body senses stillness), there is a momentary panic in which you slam your foot into the brake harder. Is it possible that some children feel this moment of disquietude often, and it contributes to their overall anxiety?
This motion-sensing capability directly affects another function of the vestibular system, the ability to stay oriented in a space, and to objects around you. This provides us with perspective; both the visual perspective of objects around us, and the overall perspective of where we are within a space.
It is difficult to understand the world without the perspective provided through spatial orientation. It creates a lack of understanding of spatial relationships. My little friend Courtney suffered from great anxiety during bath time, because she was sure that her bath toys would travel down the drain with the water when the plug was pulled. No amount of showing her how they won’t fit could ease her anxiety. Only when she began to have a sense of her own movement through space, could she understand that things “seem larger” when they are near, but retain their size when they “seem smaller” because they are further away.
Navigation in Space
The skill of spatial orientation also provides an ability to place ourselves on the “Marauder’s Map” in our minds, which encompasses the physical space within a building or room. Without this You-Are-Here sense, we can become disoriented when the visual scene before us changes, as we move through space. We might develop an anxiety related to finding our way back to a place of familiarity.
The lack of perspective is a potential explanation of unusual behavior of my friend’s son, who has autism. Every time he visited a friend’s house, he went straight to the freezer. Every house had one, and this might have been his way of orienting to a space that was, in all other ways, incomprehensible to him. He oriented to the freezer. As long as he knew where that was in the house, he knew where he was in relation to it.
The vestibular system helps us understand how we move through the world, but it also helps us plan to move from stillness. To initiate movement from a standstill, we must first know what direction we want to move in, then understand the corresponding muscle contractions necessary to move us in that direction. This skill can be exercised by visually interacting with the world. We see the bathroom across the hall, and we move in that direction. But, without the inherent understanding of what causes the body to move through space, a child may have difficulty staying oriented. It might be best to illustrate this through two clinical examples.
Kevin was a sweet nine-year-old who tried his best, but was failing in school, could not draw a coherent picture of himself, and was unable to tell me what street he lived on, or town he was in. While not the primary focus of treatment, his mother was pleasantly surprised that his life-long fear of bridges had improved greatly during treatment. In particular, we were able to cross a pedestrian bridge that used to cause him excessive anxiety. Before treatment, Kevin navigated in his immediate space by seeing an object, and proceeding there. In the case of seeing the edge of the bridge, he became obsessed with not heading there-- he wanted to stay safe. But because he was not used to navigating via an inherent understanding of where he was and how to choose his direction, he did not feel that he could avoid the edge of the bridge.
Seven-year-old Bradley suffered from a fear that was equally difficult to understand. Some nights before bed, he would make his mother promise not to jump out the window during the night. No amount of discussion could allay his fear. Like Kevin, Bradley did not understand the physical, muscular and mental coordination that initiate moving in a particular direction. He felt things in the physical world happen randomly. Because he didn’t understand how he controlled the direction of his own body, he assumed his mother lacked this control as well. How could he keep her safe? These two examples are sad, as the anxiety for these boys was impacting their happiness and that of their family. I’m happy that both of these issues were resolved after vestibular treatment.
The final capacity closely linked to the vestibular system as outlined by Fitzpatrick and Day, is ocular-motor control. There are direct neural links from the vestibular system to the six muscles that control the direction of each eyeball within the eye socket. These connections help keep our vision stationary, as we move and keep our head stable as we move our eyes around our visual field, giving us better coordination with objects in the world around us.
Very often, a child with poor ocular-motor control will visually “lock on” to objects around them to stay oriented. This dependence on vision over internal, vestibularly-provided awareness, does not always present a problem itself. The problem may become obvious when a child has trouble controlling their eye movement through a space, such as when reading or searching the environment for a specific object. This lack of ability to scan can create nervousness regarding misplacing or losing treasured objects. As a result, a child may carry objects from place to place, obsessively check on objects or people, or have excessive tantrums related to leaving objects at home, when they wouldn’t be appropriate to take along. The underlying fear for the child is that they will not be able to locate those things again.
A Different Way to Approach Anxiety
If you have an anxious child in your house, there may be a variety of reasons for their apprehension. They may have auditory processing issues, not touched on in this article. Some foreboding, stems from real fears related to lived experiences, such as abuse or neglect. Those fears may not be part of a child’s memory, as the trauma may have occurred at an age before memory fully forms. Some fears are a normal part of childhood; fear of the dark, fear of dogs, fear of storms. Not every anxiety has a root in a dysfunctional vestibular system. But, helping a child have a more accurate sense of their place in the world and a more coordinated way to move through it, can positively impact anxiety. As a caregiver, it is always a good idea to have multiple lenses through which to observe a child’s behavior, so that the root cause can be addressed in the most comfortable, and comforting way for the child. To that end, an occupational or physical therapist trained in vestibular treatment, and possibly in Ayres Sensory Integration Therapy, may be a good starting point.
ABOUT THE AUTHOR:
Robin Abbott, MS, OTR is a pediatric occupational therapist and author of the book Sound Advice: Helping Your Child with SPD, Autism and ADHD From the Inside Out, from which this article is adapted. She can be contacted through www.booksoundadvice.com
Read the article here.