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Description
Sudden Sensorineural Hearing Loss (SSHL), or sudden
deafness, is a rapid loss of hearing. SSHL can happen
to a person all at once or over a period of up to 3
days. It should be considered a medical emergency. A
person who experiences SSHL should visit a doctor immediately.
A doctor can determine whether a person has experienced
SSHL by conducting a normal hearing test. If a loss
of at least 30 decibels in three connected frequencies
is discovered, it is diagnosed as SSHL. A decibel is
a measure of sound. A decibel level of 30 is half as
loud as a normal conversation. A frequency is another
way of measuring sound. Frequencies measure sound waves
and help to determine what makes one sound different
from another sound.
Hearing loss affects only one ear in 9 out of 10 people
who experience SSHL. Many people notice it when they
wake up in the morning. Others first notice it when
they try to use the deafened ear, such as when they
make a phone call. Still others notice a loud, alarming
"pop" just before their hearing disappears.
People with SSHL often experience dizziness or a ringing
in their ears (tinnitus),
or both.
Some patients recover completely without medical intervention,
often within the first 3 days. This is called a spontaneous
recovery. Others get better slowly over a 1 or 2 week
period. Although a good to excellent recovery is likely,
15 percent of those with SSHL experience a hearing loss
that gets worse over time.
Approximately 4,000 new cases of SSHL occur each year
in the United States. It can affect anyone, but for
unknown reasons it happens most often to people between
the ages of 30 and 60.
Causes/Diagnosis
Though there are more than 100 possible causes of sudden
deafness, it is rare for a specific cause to be precisely
identified. Only 10 to 15 percent of patients with SSHL
know what caused their loss. Normally, diagnosis is
based on the patient's medical history. Possible causes
include the following:
- Infectious diseases,
- Trauma, such as a head injury,
- Abnormal tissue growth,
- Immunologic diseases such as Cogan's syndrome,
- Toxic causes, such as snakebites,
- Ototoxic drugs (drugs that harm the ear),
- Circulatory problems,
- Neurologic causes such as multiple sclerosis,
- Relation to disorders such as Ménière's
disease.
Treatment
People who experience SSHL should see a physician immediately.
Doctors believe that finding medical help fast increases
the chances for recovery. Several treatments are used
for SSHL, but researchers are not yet certain which
is the best for any one cause. If a specific cause is
identified, a doctor may prescribe antibiotics for the
patient. Or, a doctor may advise a patient to stop taking
any medicine that can irritate or damage the ear.
The most common therapy for SSHL, especially in cases
with an unknown cause, is treatment with steroids. Steroids
are used to treat many different disorders and usually
work to reduce inflammation, decrease swelling, and
help the body fight illness. Steroid treatment helps
some SSHL patients who also have conditions that affect
the immune system, which is the body's defense against
disease.
Another common method that may help some patients
is a diet low in salt. Researchers believe that this
method aids people with SSHL who also have Ménière's
disease, a hearing and balance disorder.
Research
Two factors that help hearing function
properly are good air and blood flow inside the ear.
Many researchers now think that SSHL happens when important
parts of the inner ear do not receive enough oxygen.
A common treatment for this possible cause is called
carbogen inhalation. Carbogen is a mixture of oxygen
and carbon dioxide that seems to help air and blood
flow better inside the ear. Like steroid therapy, carbogen
inhalation does not help every patient, but some SSHL
patients taking carbogen have recovered over a period
of time.
Source: National Institute on Deafness & Other
Communication Disorders, 2000.
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