Q:
I am an instructor with a
student experiencing some
equalization difficulty. He
is in his mid 20s and had tubes in
his ears as a child. Though he has
completed most sessions and dives
without a problem, once while in
the pool and once after an ocean dive he came to the surface
and reported feeling dizzy. Both times I had him rest for a
few minutes, and he seemed fine after that. Do you have any
ideas about what might be causing this?
A:
What you are describing is not at all uncommon.
Some people are very sensitive to changes in
barometric pressure, and these changes can trigger
dizziness. Although the cause of your student’s symptoms is
difficult to determine without additional information, it may be
related to asymmetrical stimulation of his inner ears.
Whenever we equalize our ears, the middle ear receives
small amounts of air through the Eustachian tubes to
compensate for the barometric pressure on the outside of the
eardrum. The middle-ear space lies adjacent to the inner ear,
and changes in middle-ear pressure may influence adjacent
inner-ear structures. The inner ear serves not only as an
auditory organ, but also provides our brains with information
about body position, movement and acceleration. When inner-
ear stimuli are asymmetrical between the right and left ears,
this can cause dizziness or even vertigo (sensation of spinning).
When these symptoms result from a pressure differential
between the ears, this is known as alternobaric vertigo.
A medical history of ear tubes is not necessarily a problem
for divers, but it is possible your student may need additional
time to equalize and may be at a higher risk for ear barotrauma
(although his dizziness is not related to this risk).
Advise your student to consult an ear, nose and throat
physician (ENT). It is not necessary to seek out a physician
trained in dive medicine, as any ENT should be perfectly able
to understand the stresses divers undergo. A consultation
with an ENT may provide options that make equalization
easier and may help prevent injuries. Should the ENT have
any dive-specific concerns, encourage him or her to contact
DAN.
AD
— Matias Nochetto, M.D., DAN director of operations and
outreach, and John U. Lee
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RESEARCH, EDUCATION & MEDICINE
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F R O M T H E M E D I C A L L I N E
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