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AUDIOGRAM
An audiogram is a test that shows the sounds a person can
hear at different frequencies and intensities. Both the right and left ears are
tested. The test results are displayed
in a graph. The frequencies are marked
along the horizontal axis from low frequency to high frequency. The sound intensity is marked on the vertical
axis from soft to loud on a decibel log scale.
The closer the marks are to the
top of the graph, the better the hearing.
The most important frequencies for hearing are located
between 250 to 2000 Hz. Sometimes a high frequency hearing loss may result in “ringing
in the ears” or tinnitus.
During a hearing test, sounds are presented to the ears in
different ways. Testing can be performed with insert earphones, headphones, or
loudspeakers. The sounds go into the ear
canal, through the middle ear to reach the inner ear. This is known as air
conduction testing. Air conduction
testing looks at how the whole hearing system responds to sound.
If there is a hearing loss detected on air conduction,
another device called a bone vibrator is placed behind the ear to send sounds
directly to the inner ear. Sounds are sent through the bones of the head and do
not pass through the eardrum or the middle ear. This is called bone conduction
testing.
The audiogram is often performed in an audio booth, which
is fabricated to reduce outside sound.
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