36
Select the ear to be tested with the RIGHT or LEFT button. Next,
select the desired screening intensity by rotating the dB HL knob to the
appropriate position. The American Speech Language and Hearing Asso-
ciation recommends 20 dB HL as the screening level for school-aged
children. Select the desired frequency at which to start the test by pressing
the Hz or Hz button. Present the selected tone via the present
bar. If the individual fails to respond, increase the intensity by 10 dB and try
again. Press the SAVE button at the intensity level where the individual
responded. Continue the procedure for all the desired frequencies.
These results can be printed in an audiogram or tabular format. Check
the Program mode to determine which setting has been selected.
3.10.2 Threshold Audiometry
1) Carefully position the earphones as described above, and select
the ear to be tested first.
2) Familiarize the individual with the test protocol by presenting a
tone of 40 dB HL at 1000 Hz.
3) Set HL control to -10 dB.
4) Practice: Beginning with the tone continuously on (Present Bar
held down) gradually increase the intensity by turning the HL con-
trol until a response occurs. Switch the tone off for at least two
seconds and present the tone again at the same level. If there is
a second positive response, proceed to threshold measurement.
If a second response does not occur, repeat this step. Practice is
preliminary to threshold measurement determination and is to be
completed at each new frequency setting.
5) The level of the first presentation shall be 10 dB below the level at
which the subject responded during the familiarization procedure.
Present the tone for a period of one or two seconds. Time between
tones can be varied, but not shorter than the duration of the test tone
itself. After each failure to respond to a signal, the level is increased
by 5 dB until the first response occurs. After the response, the inten-
sity is decreased 10 dB and another ascending series is begun.
NOTE
Descend in 10 dB steps and ascend in 5 dB steps.
6) The threshold is considered to be the minimum dial setting at
which a response has occurred two times on an ascending scale.
7) Press the SAVE button to store the threshold level for a par-
ticular frequency. Note that the appropriate symbol (
O
= right,
X
= left) appears at the correct intensity level where the threshold
was determined.
8) Repeat this test sequence for each frequency to be tested, typi-
cally 1000, 2000, 3000, 4000, 6000, 8000. Retest 1000 followed by
500 and 250. If there is a difference of 20 dB or more between two
successive octaves, test the inter-octave responses, i.e. 750, 1500.
9) Once thresholds have been obtained for all the desired frequencies,
select the other ear and repeat the sequence. Note that the dis-
play changes to a new screen for storing the second ear’s results.
R
L
M+
M+
