The 3 basic hearing tests are:
Test / Immitance Testing
We will now explain each of these tests in more detail with the
use of easy understandable terms
Tone tests provide information
about how softly a person can hear tones of different frequencies (pitches). Most sounds are between the
frequencies of 125HZ and 8000Hz. Low frequencies are lower numbers and high frequencies the higher
numbers. Tone tests have 2 parts, air conduction
and bone conduction.
tests evaluate all parts of the hearing mechanism (the outer, middle and
inner ear areas and also the hearing nerve). A person wears a
headphone in a soundproof booth and
the acoustician then presents the sounds using an instrument called an audiometer.
The patient is asked to respond whenever a tone is heard and the tester
finds the softest level that a tone is heard at least 50% of the time at
tests evaluate only the inner ear and the hearing nerve and are done if the
air conduction tests revealed a hearing loss. The patient has a small
bone-conduction vibrator placed on the bone directly behind the ear and the
sound from the audiometer is sent through the bone vibrator instead of the
headphones. The patient is tested for threshold at each of the frequencies
again. By testing the whole hearing system (air conduction) and then just
part of the system (bone-conduction), acousticians can discover which part of the
hearing mechanism is not working properly.
Speech tests are done to 'double
check' that the pure tone tests results were accurate and also to give even more information
about how we hear. A
person may be able to HEAR speech (threshold), but not UNDERSTAND speech (discrimination). Speech
testing includes both Speech threshold and speech discrimination tests. During these tests,
the patient wears headphones just like the test for air conducted tones.
Speech threshold test
done to find out how SOFTLY a person can hear and understand speech. The
patient may be tested to find out how softly he can hear speech, how softly
they can understand speech, or they may be tested for both hearing and
understanding speech. Words are presented through the audiometer at
decreasing levels. Again the threshold is determined by the softest that can
be correctly identified at least 50% of the time.
done to find out how well a person can discriminate or distinguish words
presented at comfortable levels. A list of words are presented and the
patient is asked to repeat the words back. The words are at a volume
level that the patient finds both comfortable and loud enough to provide the
best possible results. The list of words that are used reflect the sounds of
the language of the patient. Speech testing may be done via recorded voices
(male or female), or via monitored live voice. In this case the individual
giving the test watches a meter to make sure that their voice is being
presented at the proper intensity.
COMPLIANCE TEST / IMMITANCE TEST
The purpose of this test
is to evaluate how well the middle ear is working. The tester will place a small probe into the patient's ear
that will seal the air in the canal. A small pump will then take some air out of the canal and then put extra
air back into the canal to see how well the eardrum moves in and out. There is usually no
pain at all, just
a slight feeling of pressure in the ear.