This vertigo is a common problem among divers. During the descent and more often during the ascent, especially in the vertical position, the pressure variation in the middle ear may not take place simultaneously in both ears. This may result in a transient feeling of dizziness, disorientation and nausea. It is usually a feeling that lasts only a few minutes but that, occurring in depth, can have serious consequences.
IF THE DIVER IS CONFRONTED WITH THIS SITUATION, STOP AND GRASP THE SAFETY CORD OR LEAN ON THE COMPANION UNTIL THE BALANCE IS RESTORED ON THE TWO EARS AND THE SENSATION OF VERTIGO DISAPPEARS
The temperature difference can also give rise to a feeling of vertigo ( caloric vertigo ). When the diver enters the head into the water, there is usually a flood of the two ears (external ear canal) almost simultaneously. Thus, the vestibular apparatus responsible for our balance, in the inner ear, cools at a speed more or less identical in each ear.
If one of the ears is partially or completely blocked (too tight hood or wax) the water inlet and the consequent cooling are made at different speeds in both ears, resulting in a strong feeling of vertigo. A similar sensation occurs when there is perforation of the eardrum.
Like alternating vertigo, vertigo of thermal origin is usually a transient sensation. This vertigo persists until the water heats up at body temperature. These symptoms are more intense in the upright position upside down. In the upside-up position these symptoms are relieved.