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Each year more than people visit a doctor for dizziness,
and an untold number suffer with motion sickness, which is the
most common medical problem associated with travel.
Some people describe a balance problem by
saying they feel dizzy, lightheaded, unsteady, or giddy. This
feeling of imbalance or dysequilibrium, without a sensation
of turning or spinning, is sometimes due to an inner ear problem.
A few people describe their balance problem
by using the word vertigo, which comes from the Latin verb "to
turn".
They often say that they or their surroundings are turning
or spinning. Vertigo is frequently due to an inner ear problem.
Some people experience
nausea and even vomiting when riding in an airplane, automobile,
or amusement park ride, and this is called motion sickness.
Many people experience motion sickness when riding on a boat
or ship, and this is called seasickness even though it is the
same disorder.
Motion sickness or seasickness is usually just a minor annoyance
and does not signify any serious medical illness, but some travelers
are incapacitated by it, and a few even suffer symptoms for a
few days after the trip.
Dizziness, vertigo, and motion sickness
all relate to the sense of balance and equilibrium. Researchers
in space and aeronautical medicine call this sense spatial
orientation, because it tells the brain where the body is "in space:" what
direction it is pointing, what direction it is moving, and if
it is turning or standing still.
Your sense of balance is maintained by a complex interaction
of the following parts of the nervous system:
- The (also called the labyrinth), which monitor
the directions of motion, such as turning, or forward-backward,
side-to-side, and up-and-down motions.
- The , which monitor
where the body is in space (i.e. upside down, rightside up,
etc.) and also directions of motion.
- The such as in the joints and spine, which tell what part of
the body is down and touching the ground.
- The , which tell what parts of the body are
moving.
- The c (the brain and spinal cord),
which processes all the bits of information from the
four other systems to make some coordinated sense out of it
all.
The symptoms of
motion sickness and dizziness appear when the central nervous
system receives conflicting messages from the other four systems.
For example, suppose you are riding through a storm, and your
airplane is being tossed about by air turbulence. But your eyes
do not detect all this motion because all you see is the inside
of the airplane. Then your brain receives messages that do not
match with each other. You might become "air sick."
Or suppose you are sitting in the back seat of a moving car
reading a book. Your inner ears and skin receptors will detect
the motion of your travel, but your eyes see only the pages of
your book. You could become "car sick."
Or, to use a true medical condition as an example, suppose you
suffer inner ear damage on only one side from a head injury or
an infection. The damaged inner ear does not send the same signals
as the healthy ear. This gives conflicting signals to the brain
about the sensation of rotation, and you could suffer a sense
of spinning, vertigo, and nausea.
If your brain
does not get enough blood flow, you feel light headed. Almost
everyone has experienced this on occasion when standing up quickly
from a lying down position. But some people have light headedness
from poor circulation on a frequent or chronic basis. This could
be caused by arteriosclerosis or hardening of the arteries, and
it is commonly seen in patients who have high blood pressure,
diabetes, or high levels of blood fats (cholesterol). It is sometimes
seen in patients with inadequate cardiac (heart) function or
with anemia.
Certain drugs also decrease the blood flow to the brain, especially
stimulants such as nicotine and caffeine. Excess salt in the
diet also leads to poor circulation. Sometimes circulation is
impaired by spasms in the arteries caused by emotional stress,
anxiety, and tension.
If the inner ear fails to receive enough blood flow, the more
specific type of dizziness occurs-that is-vertigo. The inner
ear is very sensitive to minor alterations of blood flow and
all of the causes mentioned for poor circulation to the brain
also apply specifically to the inner ear.
A skull fracture that damages the inner ear produces
a profound and incapacitating vertigo with nausea and hearing
loss. The dizziness will last for several weeks, then slowly
improve as the normal (other) side takes over.
Viruses, such as those causing the common "cold" or "flu," can
attack the inner ear and its nerve connections to the brain.
This can result in severe vertigo, but hearing is usually spared.
However, a bacterial infection such as mastoiditis that extends
into the inner ear will completely destroy both the hearing and
the equilibrium function of that ear. The severity of dizziness
and recovery time will be similar to that of skull fracture.
Some people experience dizziness and/or vertigo attacks
when they are exposed to foods or airborne particles (such as
dust, molds, pollens, danders, etc.) to which they are allergic.
A number of diseases of the nerves can
affect balance, such as multiple sclerosis, syphilis, tumors,
etc. These are uncommon causes, but your physician will think
about them during the examination.
The doctor will
ask you to describe your dizziness, whether it is light headedness
or a sensation of motion, how long and how often the dizziness
has troubled you, how long a dizzy episode lasts, and whether
it is associated with hearing loss or nausea and vomiting.
You might be asked for circumstances that might bring on a dizzy
spell. You will need to answer questions about your general
health, any medicines, you are taking, head injuries, recent
infections, and other questions about your ear and neurological
system.
Your physician will examine your ears, nose, and throat and
do tests of nerve and balance function. Because the inner ear
controls both balance and hearing, disorders of balance often
affect hearing and vice versa. Therefore, your physician will
probably recommend hearing tests (audiograms). The physician
might order skull X-rays, a CT or MRI scan of your head, or special
tests of eye motion after warm or cold water is used to stimulate
the inner ear (ENG - electronystagmography). In some cases, blood
tests or a cardiology (heart) evaluation might be recommended.
Not every patient will require every test. The physician's judgement
will be based on each particular patient. Similarly, the treatments
recommended by your physician will depend on the diagnosis.
- ,
especially from lying down to standing up or turning around
from one side to the other.
- (especially
looking up) or rapid head motion (especially turning or twisting).
- , e.g.
nicotine, caffeine, and salt.
- , such as stress and anxiety
or substances to which you are allergic.
- when you are dizzy, such as driving an automobile or operating
dangerous equipment, or climbing a step ladder, etc.
Always ride where your eyes
will see the same motion that your body and inner ears feel,
e.g. sit in the front seat of the car and look at the distant
scenery; go up on the deck of the ship and watch the horizon;
sit by the window of the airplane and look outside. In an airplane
choose a seat over the wings where the motion is the least.
- if
you are subject to motion sickness, and do not sit in a seat
facing backward.
- immediately before and during your travel. Medical
research has not yet investigated the effectiveness of popular
folk remedies such as soda crackers and Seven Up® or
cola syrup over ice.
- before your travel begins, as recommended by
your physician.
Some of
these medications can be purchased without a prescription (i.e.,
Dramamine®, Bonine®, Marezine®, etc.) Stronger
medicines such as tranquilizers and nervous system depressants
will require a prescription from your physician. Some are used
in pill or suppository form.
Most cases of dizziness and motion sickness are mild
and self-treatable disorders. But, severe cases and those that
become progressively worse, deserve the attention of a physician
with specialized skills in diseases of the ear, nose, throat,
equilibrium, and neurological systems.
© 2004 AAO-HNS/AAO-HNSF
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