How the Body’s Balance System works:
Balance relies on three distinct systems to come together: your eyes for sight, your inner ear for vestibular input, and then the bottom of your feet for proprioception. Your brain takes all the sensory input from these three areas of the body, and with that information tells your muscles how to keep your body upright and balanced. If one of these three sensory systems is disrupted, then your body weighs more heavily on the other two.
Balance & The Eyes:
First and foremost, your brain registers all the input it can receive from your vision. Have you ever wondered why it’s so much trickier to walk around in the dead of night? That’s because in order for your body to use all of its balance system, we need light to use our vision fully. Most of the time our visual input is very reliable but, sometimes your vision can play tricks on you. Have you ever been stopped in a car, and feel like suddenly you are going in reverse because you see the cars next to you moving forward? That is one example where your visual input tricks your body into thinking you are moving.
Balance & The Inner Ear:
Your inner ear is home to the vestibular system. This system is what many talk about as the “equilibrium”. It’s like a level between your two ears that makes sure you are upright and moving your body according to your visual and proprioceptive input in order to maintain balance. Sometimes, when you get ear infections you can feel dizzy or like the world is spinning. That is because your vestibular system is getting odd signals that prevent it from sending appropriate output. In these cases, the vestibular system is the culprit for bad balance. Many people also suffer from BPPV (extreme dizziness with position changes), where the vestibular system is getting inappropriate signals from a “screw loose” in the vestibular system.
Balance & Proprioception:
Last, but certainly not least is your feet! The bottom of your feet send information to your brain about the type of terrain (grass vs. concrete, flat vs. bumpy, soft, vs. hard etc), to help you balance as well. Just like your other two mechanisms, this is usually a reliable system, but it can be tricked too. Diabetics often have neuropathy in their feet which can make them lose some sensation in their feet. This can disrupt the proprioception signals to the brain from your feet, and in turn affect your balance.
How can we Influence Balance with these 3 mechanisms in the Clinic?
Balance can be challenged many ways in the clinical settings and everyday life. If you “knock out” one of the three systems, your body relies on the other ones more so. Therefore if you close your eyes, you knock out the visual system. Then, your body relies more heavily on your feet for proprioception, and your inner ear for vestibular input. This then allows you to target these systems, so your body can use them more efficiently for balance input.
You can also change the surface you stand on to alter proprioception input. If you stand on a soft or compliant surface, it alters your feet’s ability to provide proper input. Then, your body has to rely on its eyes and ears more heavily. I am sure as you can guess by this point, if you close your eyes and stand on a soft surface (like a balance pad) your body relies solely on vestibular input for balance.