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A balance disorder is a
disturbance that causes an individual to feel unsteady, giddy, woozy, or
have a sensation of movement, spinning, or floating. An organ in our
ear, the labyrinth, is an important
part of our vestibular (balance) system. The labyrinth interacts with
other systems in the body, such as the visual (eyes) and skeletal (bones
and joints) systems, to maintain the body's position. These systems, along
with the brain and the nervous system, can be the source of balance
Three structures of the labyrinth, the semicircular canals, let us know
when we are in a rotary (circular) motion. The semicircular canals, the
superior, posterior, and horizontal, are fluid-filled. Motion of the
tells us if we are moving. The semicircular canals and the visual and
skeletal systems have specific functions that determine an individual's
orientation. The vestibule is the region
of the inner ear where the semicircular canals converge, close to the cochlea (the
hearing organ). The vestibular system works
with the visual system to keep objects in focus when the head is moving.
Joint and muscle receptors also are important in maintaining balance. The
brain receives, interprets, and processes the information from these
systems that control our balance.
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Movement of fluid in the semicircular canals signals the brain about
the direction and speed of rotation of the head--for example, whether
are nodding our head up and down or looking from right to left. Each
semicircular canal has a bulbed end, or enlarged portion, that contains
hair cells. Rotation of
the head causes a flow of fluid, which in turn causes displacement of the
top portion of the hair cells that are embedded in the jelly-like cupula.
Two other organs that are part of the vestibular system are the utricle
and saccule. These are called the otolithic organs and are responsible for
detecting linear acceleration, or movement in a straight line. The hair
cells of the otolithic organs are blanketed with a jelly-like layer
studded with tiny calcium stones called otoconia. When the head is tilted
or the body position is changed with respect to gravity, the displacement
of the stones causes the hair cells to bend.
The balance system works with the visual and skeletal systems (the
muscles and joints and their sensors) to maintain orientation or balance.
For example, visual signals are sent to the brain about the body's
position in relation to its surroundings. These signals are processed by
the brain, and compared to information from the vestibular and the
skeletal systems. An example of interaction between the visual and
vestibular systems is called the vestibular-ocular reflex. The nystagmus
(an involuntary rhythmic eye movement) that occurs when a person is spun
around and then suddenly stops is an example of a vestibular-ocular
flow in the horizontal semicircular canals: AC--anterior canal,
PC--posterior canal, HC--horizontal
canal." llustration C
This figure shows nerve activity associated
with rotational-induced physiologic nystagmus and spontaneous
nystagmus resulting from a lesion of one labyrinth. Thin straight
arrows--direction of slow components; thick straight
arrows--direction of fast components; curved arrows--direction of
endolymph flow in the horizontal semicircular canals: AC--anterior
canal, PC--posterior canal, HC--horizontal
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When balance is impaired, an individual has difficulty maintaining
orientation. For example, an individual may experience the "room spinning"
and may not be able to walk without staggering, or may not even be able to
arise. Some of the symptoms a person with a balance disorder may
- A sensation of dizziness or vertigo
- Falling or a feeling of falling.
- Lightheadedness or feeling woozy.
- Visual blurring.
Some individuals may also experience nausea and vomiting, diarrhea,
faintness, changes in heart rate and blood pressure, fear, anxiety, or
panic. Some reactions to the symptoms are fatigue, depression, and
decreased concentration. The symptoms may appear and disappear over short
time periods or may last for a longer period of time.
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Infections (viral or bacterial), head injury, disorders of blood
circulation affecting the inner ear or brain, certain medications, and
aging may change our balance system and result in a balance problem.
Individuals who have illnesses, brain disorders, or injuries of the visual
or skeletal systems, such as eye muscle imbalance and arthritis, may also
experience balance difficulties. A conflict of signals to the brain about
the sensation of movement can cause motion sickness (for instance, when an
individual tries to read while riding in a car). Some symptoms of motion
sickness are dizziness, sweating, nausea, vomiting, and generalized
discomfort. Balance disorders can be due to problems in any of four areas:
- Peripheral vestibular disorder, a disturbance in the
- Central vestibular disorder, a problem in the brain or its
- Systemic disorder, a problem of the body other than the head and
- Vascular disorder, or blood flow problems.
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Some of the more common balance disorders are:
Positional Vertigo (BPPV)--a brief, intense sensation of vertigo
that occurs because of a specific positional change of the head. An
individual may experience BPPV when rolling over to the left or right upon
getting out of bed in the morning, or when looking up for an object on a
high shelf. The cause of BPPV is not known, although it may be caused by
an inner ear infection, head injury, or aging.
infection or inflammation of the inner ear causing dizziness and loss of
disease--an inner ear fluid balance disorder that causes episodes
of vertigo, fluctuating
hearing loss, tinnitus (a ringing or
roaring in the ears), and the sensation of fullness in the ear. The cause
of Ménière's disease is unknown.
neuronitis--an infection of the vestibular nerve, generally viral.
fistula--a leakage of inner ear fluid to the middle ear. It can
occur after head injury, physical exertion or, rarely, without a known
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Diagnosis of a balance disorder is complicated because there are many
kinds of balance disorders and because other medical conditions--including
ear infections, blood
pressure changes, and some vision problems--and some medications may
contribute to a balance disorder. A person experiencing dizziness should
see a physician for an evaluation.
The primary physician may request the opinion of an otolaryngologist
to help evaluate a balance problem. An otolaryngologist is a
physician/surgeon who specializes in diseases and disorders of the ear,
nose, throat, head, and neck, with expertise in balance disorders. He or
she will usually obtain a detailed medical history and perform a physical
examination to start to sort out possible causes of the balance disorder.
The physician may require tests to assess the cause and extent of the
disruption of balance. The kinds of tests needed will vary based on the
patient's symptoms and health status. Because there are so many variables,
not all patients will require every test.
Some examples of diagnostic tests the otolaryngologist may request are
a hearing examination, blood tests, an electronystagmogram (ENG--a test of
the vestibular system), or imaging studies of the head and brain.
The caloric test may be performed as part of the ENG. In this test,
each ear is flushed with warm and then cool water, usually one ear at a
time; the amount of nystagmus resulting is measured. Weak nystagmus or the
absence of nystagmus may indicate an inner ear disorder.
Another test of the vestibular system, posturography, requires the
individual to stand on a special platform capable of movement within a
controlled visual environment; body sway is recorded in response to
movement of the platform and/or the visual environment.
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There are various options for treating balance disorders. One option includes
treatment for a disease or disorder that may be contributing to the balance
problem, such as ear infection, stroke, or multiple sclerosis. Individual treatment
will vary and will be based upon symptoms, medical history, general health,
examination by a physician, and the results of medical tests.
Another treatment option includes balance retraining exercises
(vestibular rehabilitation). The exercises include movements of the head
and body specifically developed for the patient. This form of therapy is
thought to promote compensation for the disorder. Vestibular retraining
programs are administered by professionals with knowledge and
understanding of the vestibular system and its relationship with other
systems in the body.
For people diagnosed with Ménière's disease, dietary changes such as
reducing intake of sodium may help. For some people, reducing alcohol,
caffeine, and/or avoiding nicotine may be helpful. Some aminoglycoside
antibiotics, such as gentamicin and streptomycin, are used to treat
Ménière's disease. Systemic streptomycin (given by injection) and topical
gentamicin (given directly to the inner ear) are useful for their ability
to affect the hair cells of the balance system. Gentamicin also can affect
the hair cells of the cochlea,
though, and cause hearing loss. In cases that do not respond to medical
management, surgery may be indicated.
A program of talk therapy and/or physical rehabilitation may be recommended
for people with anxiety.
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You can take the following steps that may be helpful to your physician
in determining a diagnosis and treatment plan.
- Bring a written list of symptoms to your doctor.
- Bring a list of medications currently being used for balance
disorders to your doctor.
- Be specific when you describe the nature of your symptoms to your
doctor. For example, describe how, when, and where you experience
Lastly, remember to write down any instructions or tips your doctor
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Scientists are working to understand the various balance disorders and
the complex interactions between the labyrinth, other balance-sensing
organs, and the brain. Scientists are studying eye movement to understand
the changes that occur in aging, disease, and injury. Scientists are
collecting data about eye movement and posture to improve diagnosis and
treatment of balance disorders. Scientists are also studying the
effectiveness of certain exercises as a treatment option.
Recent findings from studies supported by the National Institute on
Deafness and Other Communication Disorders (NIDCD) suggest that the
vestibular system plays an important role in modulating blood pressure.
The information from these studies has potential clinical relevance in
understanding and managing orthostatic hypotension (lowered blood pressure
related to a change in body posture). Other studies of the otolithic
organs, the detectors of linear movement, are exploring how these organs
differentiate between downward (gravitational) motion from linear
(forward-to-aft, side-to-side) motion.
Other projects supported by NIDCD include studies of the genes
essential to normal development and function in the vestibular system.
Scientists are also studying inherited syndromes of the brain that affect
balance and coordination.
The Institute supports research to develop new tests and refine current
tests of balance and vestibular function. For example, scientists have
developed computer-controlled systems to measure eye movement and body
position by stimulating specific parts of the vestibular and nervous
systems. Other tests to determine disability, as well as new physical
rehabilitation strategies, are under investigation in clinical and
NIDCD, along with other Institutes at the National Institutes of
Health, joined the National Aeronautics and Space Administration (NASA)
for Neurolab, a research mission dedicated to the study of life sciences.
Neurolab focused on the most complex and least understood part of the
human body, the nervous system (including the balance system).
Exposure to the weightlessness of space is known to temporarily disrupt
balance on return to Earth and to gravity. A team of NIDCD and NASA
investigators had previously studied the effects of microgravity exposure
on balance control in astronauts who had returned from short-duration
space flight missions, but these studies did not include an aged
individual. During the October 29-November 7, 1998, Space Shuttle
Discovery mission, NIDCD and NASA collaborated in another study of
postflight balance control. For the first time, a previously experienced,
but now elderly astronaut, Senator John Glenn, participated. Data
collected during this mission, which are still being analyzed, may help to
explain the mechanisms of recovery from balance disorders experienced on
Earth as well as in the space environment. Scientists also hope that this
data will help to develop strategies to prevent injury from falls, a
common occurrence among people with balance disorders, particularly as
they grow older.
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American Academy of Otolaryngology-Head and Neck Surgery
EAR Foundation (EF)
Vestibular Disorders Association (VEDA)
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