Audio Traveler AA222, Operation Manuals, Page: 27 / 141

AA222 Operation Manual Page 27
signal button shall be carried out: "You will now hear different
tones in the earphones with various intensities. Please push the
signal button when you hear the tone and release it when you do
not hear the tone".
Threshold Determination:
The test normally starts at 1000 Hz on the patient's best ear.
Familiarisation:
Present a tone of 40 dB to the test ear. Often this tone is
sufficient to evoke a clear response from the subject. Then
present a tone completely attenuated. If the subject does not
respond to a tone of 40 dB present tones that are successively
10 dB higher until a response occurs. Then reduce the tone
level by 20 dB.
In either case gradually increase the level until a response
occurs. Repeat the tone presentation at the same level. If the
responses are consistent, the familiarisation is completed. If not,
it should be repeated.
Threshold Determination using the Ascending Method:
1) Present a tone which is 10 dB lower than the threshold
obtained during the familiarisation procedure. If response
fails, increase in 5 dB steps until the subject responds.
2) Decrease the level by 10 dB and begin another ascending
level series. Continue until three responses out of a
maximum of five occur at the same level.
Almost the same results will be obtained, when two
responses out of three tone presentations occur at the same
level and frequency. If less than two responses out of three
(or less than three out of five) have been obtained at the
same level, present a tone 10 dB higher than the last
response and repeat the procedure.
3) Proceed to the next frequency. Decrease the level by 10 dB
and begin another ascending level series. Continue until
three responses out of a maximum of five occur at the same
level.