There has been a lot of talk lately about football and deflated balls. Only in the world of vestibular geekology could one find a connection between these events and vestibular compensation. But, you have to find your inspiration where you can, so here goes:
I will use the analogy of an old football injury and generalized deflation to discuss how aging can affect vestibular compensation. Think about that old football injury. You might have injured a knee back in high school, but with time, rehabilitation and luck, you recovered and got back out on the field in a few weeks. You haven’t thought about that knee injury in many years. Lately, though, it seems to be bothering you a bit more. You notice it aches when you are tired, and it feels a little less stable than the other knee. What’s going on? You haven’t reinjured the knee, why is it bothering you so many years later?
It is possible that as you age, the muscles surrounding the knee have gotten weaker (deflated), reducing stability. It is also possible that you weigh a bit more and the knee has to work harder at stabilizing you than it used to.
Let’s take the leap now to vestibular compensation. After an acute vestibular injury, the brain initially responds with “cerebellar clamp” to reduce the acute symptoms of vertigo and nausea. But, after several days the process of compensation begins as soon as you start moving around again. When you are young and otherwise healthy, you may recover well even without intervention and therapy. Your brain will automatically start using the parts of the balance system that it finds to be reliable. It may ideally use the healthy ear on the other side, and/or use residual function in the damaged ear. Your brain may determine that your visual or tactile feedback are now more reliable than your vestibular response and make you more dependent on these senses for balance and orientation. You may rely on strong muscles and quick reflexes to help you maintain balance in challenging situations. This may all work so well that you could go years without a diagnosis of a chronic vestibular disorder, because your balance function was satisfactory.
Jump twenty or thirty years ahead, and that vestibular injury might start showing itself even though nothing has changed in the ear in all those years. What has changed is that the parts of the body that worked overtime to compensate for the vestibular injury are now starting to fade with age. Your eyes aren’t as good as they once were. You reflexes are a little slower, your muscles a little weaker. They are no longer able to effectively “pick up the slack” for the vestibular weakness.
While it is true that some vestibular injuries heal over time, many are permanent and rely on alternatives to maintain balance, orientation and visual clarity during movement. It is not unusual for us to find a caloric weakness in a patient that describes an episode of severe vertigo thirty years earlier, but only recently started complaining of balance issues. The hypothesis is that they are experiencing gradual age related decompensation, and may need to begin a program of vestibular rehabilitation exercises to maintain or improve their equilibrium.