Welch Allyn REF 29400 User Manual

Page 27

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Welch Allyn OAE Hearing Screener Directions for Use 705353 Rev E

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After 10 tests have been performed, the next test (test 11) will overwrite the first test. This
proceeds in a continuous loop so that only the last 10 tests performed are saved and accessible in
memory. Once overwritten, a test cannot be retrieved. If you wish to record or print the details of
a test, it is important that you do so before it is overwritten.

Increase Artifact Reject Level:

During a test you can increase the artifact rejection threshold in small increments by pressing and
holding down the DX SELECT button until the message PLEASE RELEASE BUTTON! flashes on
the LCD. It may take a few seconds to see the change on the LCD since the display only updates
every few seconds. The default artifact rejection threshold is 30 mPa. Each press of the DX
SELECT button increases the artifact rejection level by 20 mPa and this will be displayed on the
LCD. This feature can be used when a high percentage of data samples are being rejected from
averaging caused by a noisy environment or patient, resulting in prolonged test time. However,
increasing the artifact rejection threshold allows more noise into the average and that may
confound interpretation of the data. If possible, try to control the environmental or patient noise
instead of increasing the artifact rejection threshold. However, newborns and infants often
produce high levels of internal noise just due to breathing and the artifact rejection threshold may
have to be increased in order to collect any data successfully. This procedure will have to be
repeated for each test frequency in the DPOAE test.

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