Falling can occur due to vestibular disease, but also happens in normal people. Humans stand on two feet, which is much less stable than the four-footed mobility of most animals. To master this, we had to develop a tight system of reflexes and feedback to our balance system. There are three critical areas:
1) The vestibular system of the inner ears and brain. This keeps your brain informed about any head movements that occur and sends out appropriate reflexes to the eyes and body.
2) Vision, including 3-D vision and visual tracking. Vision overlaps with the inner ear in keeping track of head movements. It also gives feedback if vision is blurred by movement that helps fine-tune the reflexes.
3) Sensation, strength and mobility in the legs and feet. The arms, hands and neck are also part of this system. These body parts need to be able to respond smoothly and quickly to the reflex information being sent to the balance system and give feedback about the ground or environment that is conveyed by touch and position sensors.
If all these areas are normal, you can still fall under certain circumstances. For example, if you tried to walk across a patch of ice on a dark night, you would not be surprised if you fell. Darkness prevents you from using vision and visual tracking to assist with balance, and ice is a challenging and unforgiving surface.
Preventing a fall becomes more difficult if one or more of the three key balance areas are impaired. For example, when a person is blind, they can easily trip and fall over an unexpected object on the ground. Using a cane to feel the environment just ahead of the feet while walking is one way to get around this problem. It is also important to have 3-D (binocular) vision. If you have clear vision in only one eye, balance is impaired a little.
People with numbness in the feet, or joint problems causing stiffness in the legs or feet also experience balance limitations. If you cannot feel the ground, you are more likely to trip with a change in texture of the floor, like moving from a smooth floor to carpet. This can be helped by using a cane or walker to allow you to feel the ground through information transmitted up the cane to the hand.
Finally, if you have a vestibular problem, you will not receive correct information about head movement and can have inappropriate reflex responses to movement. This can cause you to tilt your body in a way that makes you more likely to fall, as we discussed in the prior blog.
Another factor that makes a person more likely to fall is their approach to risk-taking. A person who skis or goes rock-climbing is more likely to have a fall than one who does not. Going up a flight of stairs carrying groceries in both hands is more likely to cause a fall than going up the stairs while holding the railing. If you have any visual impairment, loss of sensation or mobility in the legs, or a vestibular disorder, you should take extra care while walking and may want to consider a support aid such as a cane or walker. Avoid dark areas, unstable footing, and moving at high speeds.
There are other symptoms of vertigo disorders besides dizziness and imbalance. We’ll start off with a very distressing one in our next post: nausea.