Operating Instructions MA 50
Geba_MA50_Fe_11a.doc
9 851 406/2 11/11
4 Pure tone audiometry
4.1 Air Conduction (AC) Testing
In the hearing threshold test, the hearing threshold
of the patient is measured in comparison with the
normal hearing threshold for air conduction. The
test is started on the ear with better hearing.
-
The patient should sit at a distance of at least
1 m from the device.
-
Eliminate any obstructions which will
interfere with the placement of the earphone
cushions on the ear (i.e. hair, eyeglasses).
-
Ensure the headphones are put on correctly.
Red side on the right, blue side on the left. Adjust the headband of the
headphones
so
that
the
receivers are at the correct
height (the sound output grid
exactly facing the ear canal).
Start
with
the
“better”
indicated ear at 1 kHz. (After
switching on, the frequency is
automatically set to 1 kHz.) In
the following example we
assume that the right is the
“better” ear.
-
Set the receiver selector
to AC.
-
Set the left level control
knob
↕ to a value just below
expected hearing loss.
-
Explain to the patient
that he should press the button
of the patient response switch
if he just hears the test tone.
-
Press the STIM bar
↔ for a certain time to present the test tone. The
STIM LED
should light on.
-
If the patient hears the test tone, the patient response display
lights
red. In this case decrease the level with the level control knob
↕. Proceed
with presenting the test signal as described before.
-
If the patient doesn’t hear the test tone, increase the level with the
level control knob
. Proceed with presenting the test signal as described
before.
-
When you find a stable threshold value, note the level and frequency. If
the MA 50 is connected to a PC, the value was stored with your last STIM
presentation.
Picture 10 Headphone
Picture 11 MA 50 controls and display for
airconduction threshold test
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