Vertigo
Which Way Is Up?
It feels exactly like way too many beers, and often leads to the same nausea. Unfortunately, this case of the “whirlies” probably won’t be gone in the morning.
Vertigo, the sense that the world is spinning around you, is a common symptom of middle-ear or inner-ear injury. That’s because your balance mechanisms, called the vestibular canals, are located adjacent to both ear spaces. In fact, they’re considered part of your inner ears, and separated from the cochlea (the hearing structures) by the thinnest membranes in your body—two cells thick.
If vertigo happens under water, you may not be able to tell which way is up and panic. (Emergency tip: watch the water in your mask to judge your orientation and follow your bubbles, slowly, to the surface.)
Damage to your vestibular canals, whether by DCS or by pressure shock, is usually permanent. Vertigo may go away in two to six weeks because your brain learns to compensate and ignores the side that’s damaged, but the canal will not heal. Damage the vestibular canals on the other side too, and you could be unable to drive a car, much less dive.
Vertigo can also occur from stimulation of one side and not the other—the pressure difference if only one ear equalizes or the temperature difference if cold water enters one ear but not the other. In both cases, your brain interprets unequal stimulation of your vestibular systems as movement. This type of vertigo disappears with the unequal stimulation, fortunately, and leaves no after-effects.