Interacoustics AT235 - Transducer types and equipment requirements for calibration

AT235 Additional Information Page 24
3.3 Eustachian Tube Function – Non-Perforated Eardrum
Make sure that the test labeled as Non-perforated is selected from the list of tests on the left of the screen.
The Eustachian tube function test for the non-perforated eardrum, or ETF 1, or Williams procedure is setup
to measure three tympanograms. It keeps the pressure between the first and second tympanograms at Start
pressure and between the second and third tympanograms at the Stop pressure. After testing, the
pressure is brought back to 0daPa. In between all tympanograms, a message informs you as to which
instruction should be given to the patient. The original Williams procedure asks the patient to swallow in
between the different tympanograms. We advise to ask the patient to perform Valsalva maneuver after the
first tympanogram and to swallow after the second tympanogram, because the expected deviations of the
peak pressure will then be larger.
When rotating the wheel, the following settings can be selected and changed.
A
Auto run. Once enabled for a test auto run will cause this test to be automatically run as part of
the protocol.
B
While this instruction is selected, press the button to open a pop up in which you
can alter the instruction that is shown in between the first and second tympanograms. Connect a
pc keyboard to the USB port of the AT235 for easy typing optionsincluding the use of special
characters.
C
While this instruction is selected, press the button to open a pop up in which you
can alter the instruction that is shown in between the second and third tympanograms. Connect a
pc keyboard to the USB port of the AT235 for easy typing options including the use of special
characters.
D
Start pressure. The start pressure for the three automated tympanograms is set here. The start
pressure can vary between +400 and -600 daPa.