MA 25 Operating Manual
11
Threshold Determination:
The test normally starts at 1000 Hz on the patient's better ear with the L/R switch adjusted accordingly. A
procedure of “down 10dB, up 5dB” is typically utilized to establish a threshold at each frequency.
Screening:
A hearing screening produces a “pass” or “refer” result and is used to determine if a patient should receive further
evaluation to determine if a hearing problem exists. Patients are typically screened at a level of 20dB HL at 500,
1000, 2000, and 4000HZ in each ear. If a patient hears all the tones in each ear, the result would be considered a
“pass.” Failure to hear any of the tones in either ear would result in a “refer”. This is an example of one screening
protocol. Each state may have their own screening protocol. Please contact your state health department for
guidelines in your area.
Attention: Background noise can produce false test results, especially at lower frequencies.
For hygienic reasons, it is important to clean the headphone ear cushions after testing.
4.1.
Auto Threshold:
In addition to traditional manual testing, the MA25e incorporates a
Hughson-Westlake patient controlled automatic threshold test complying
with ISO 8253. When the test is completed the results are easily recalled
from the internal memory of the MA25e.
Hughson-Westlake is a procedure used to determine puretone thresholds. The MA 25e utilizes this procedure to perform an
automatic pure tone test procedure. Threshold is defined as 2 out of 3 (or 3 out of 5) correct responses obtained at a certain
level in a 10 db decrease and 5 dB increase procedure.
