Part 1: The Sense of Balance

We all learn about our 5 senses as children: smell, touch, see, hear and taste. Our sensory systems are so important to how we experience each day. We smell the delicious food that is cooking, hear the sizzle from the pan and can’t wait to get a taste. Our sensory systems also underlie our attention, focus and motor control. An important sense that may not be part of our daily consciousness, but is integral to our ability to move, play and learn, is our sense of balance.

The Sensory Systems

Our balance system is composed of a team of sensory systems outside of the commonly known 5 senses. These include the vestibular, somatosensory and visual systems. This sensory team gives us the ability to stay upright and to keep our eyes focused as we move our heads.

The Vestibular System

The vestibular system includes a tiny but complex apparatus encased in bone in the inner ear and connects to the eyes and the brain. The vestibular system connects reflexively to the eyes to keep our eyes stable while the head moves. The vestibular nerves also travel down the spine to activate the muscles in patterns necessary to keep the body upright.

The Somatosensory System

The somatosensory system includes light touch on the skin, proprioception/body sense from the muscles and joints, temperature, pain and vibration. Information from this system provides the brain important input as to where the body is in space in order to keep your balance.

The Visual System

The visual system is composed of focal vision, which is detail-oriented and ambient vision, which is big picture oriented. Focal vision develops over time over the foundation of ambient vision that is present at birth. During the first 5 years or so of life, children develop fusion of focal and ambient vision, giving the child the ability to be aware of their entire environment visually, while attending to specifics at the same time. As stated above, vision is reflexively connected to the vestibular system, so a deficit in one system will always affect the other.

Sensory Organization

Every component of the balance team helps us to stay upright. When we are younger vision is dominant and as we get older vision plays a less dominant role. If there is a problem in one sensory area, another area will try to pick up the slack. For example, if Johnny has vestibular dysfunction, his vision and somatosensory systems can help him to keep his balance. However, what happens to Johnny in the dark? His balance might not be very good in that situation and for a young child this would likely be expressed as fear of the dark.

The Modified Sensory Organization Test (SOT) is a tool to differentiate between these 3 sensory systems to identify which system may be weaker than the others. In this test the patient performs balance tasks under different conditions:  1) standing, eyes open 2) standing, eyes closed 3) standing on a foam surface, eyes open 4) standing on a foam surface, eyes closed.  This test can help identify which member of the sensory team isn’t holding its own weight. Once this is determined, exercises to strengthen the weakened team member and reorganize the overall system can be performed to improve balance. Stay tuned for information on childhood vestibular disorders and treatment.