MIDIMATE 602 & 622 Diagnostic Audiometers
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2.
If possible, select the better ear to test first by toggling
L/R Shift
.
3.
Read from the list while you turn the
Hearing Level
wheel to find the lowest
level at which the patient can still repeat each word correctly.
4.
Turn the
Hearing Level
wheel counterclockwise to reduce the
L.Micr
level
shown above
Softkey 3
by 5 dB.
5.
Continue the test to determine the percentage of words, which the patient repeats
correctly at this level.
6.
Repeat steps 3 and 4 until the percentage of at least 20 words, which the patient
repeats correctly, falls below 50%. Make a note of both the level and the corre-
sponding percentage in each case. Normally the first few words are sufficient to
establish the patient’s score, and the remaining words serve to confirm it.
7.
Determine the patient’s hearing loss, by interpolation if necessary, from the level
corresponding to a 50% score.
8.
Toggle
L/R Shift
and repeat steps 2 to 6 for the other ear.
If necessary, repeat the procedure with progressively increasing levels.
5.1.3
Testing speech discrimination
To test a patient’s speech discrimination, do as follows:
1.
Prepare for the test as described in §5.1.1. Each of the words used for discrimina-
tion testing must be phonetically balanced. Because of the relatively high levels
used in discrimination testing, masking is usually recommended to prevent an
unwanted response from the ear not being tested.
2.
Record the score of correctly repeated words for a test conducted at a level of
40 dB above the patient’s speech threshold. At this level a patient with normal
hearing would score 100%. Patients with hearing loss resulting in reduced dis-
crimination may score as little as 40% to 50%, and for certain kinds of hearing
loss their score may be reduced at increased hearing levels.
3.
Repeat the test at other levels to determine if the score varies with level.
4.
Toggle
L/R Shift
and repeat the test on the other ear.
5.2
Testing with recorded speech
The setup for testing the patient using pre-recorded word lists is similar to the pro-
cedure described in §5.1.1, with the following differences:
1.
Connect the output of a tape recorder or CD player to
Tape 1
, and in the case of a
two-channel or stereo signal to
Tape 2
as well.
2.
Placing the patient in a sound cabin is not necessary, as there is no direct path for
the sound.
