Functioning
37
exceeds the total level of А-В noise. If the reproducibility criteria (“Reproducibility,
%”) is set in TEOAE settings, the reproducibility coefficient will be displayed in-
stead of the given criteria in percents. The reproducibility coefficient reveals the
correlation between odd and even curves of a signal.
Total residual noise level, in dB SPL is opposite the “A-B” label. The residual
noise level decreases in the process of the averaging. If OAE is not detected, i.e.
the “REFER” signature appears on the information panel after the test
termination, and the residual noise level exceeds 10 dB, it indicates highly
enough level of the external acoustic noises and means that the test should be
repeated in calmer conditions or after the probe resetting.
The bottom part of the information panel contains the table of OAE presence by
frequencies. The top line marked by “F” letter contains 1, 2, 3, 4 and 5 kHz
frequencies. The middle line marked as “SNR” displays the current signal-to-
noise ratio on the given frequency (in dB) detected with the use of the digital
bandpass filter. The OAE presence on the given frequency is marked by
““
”symbol. The criterion of its presence is the signal/noise ratio exceeding 4 dB.
The general criterion of test passing is the OAE emergence on three of five
frequencies. In this case the test is over and the “PASS” signature appears on the
information panel. If during the specified number of averaging (1000 by default),
OAE is not detected, the test is stopped and the “REFER” signature appears on
the information panel.
After the test termination, you can print the result on the wireless thermal printer by
pressing “Print” button. Before printing make sure that the printer is switched on and is
in the operating zone (up to 10 meters in the direct visibility conditions).
The exam can be closed by pressing “Close” button. At that the message box “Save
exam?” will appear on the screen. Press “Yes” button if you want to save the test
results or “No” button if you don’t. After that, you will return to the main menu.
Note: the “Close” button can be pressed at any moment of test performing. If the test is not
over, you will return to the main menu, at that, the test results are not saved.
5.7. DPOAE Test
After the selection of a patient in the list or entering new data about a patient, choose
the DPOAE technique and an ear for the exam performing (right or left) in the main
menu using the arrow buttons. If a patient is a newborn, it is desirable to perform it be-
fore the OAE probe insertion to the ear of a baby not to disturb her/him again. The
OAE probe installation should be performed according to the recommendations given
in the section 5.5 “Patient Preparation for OAE Test”.
Press “Select” button. Just after the test start, the device switches to the OAE probe
fitting control mode. The DPOAE test window appears on the display (Fig. 18). It is di-
vided into three parts. The stimulus shape is displayed in the left part of the window,
the information panel is in the right one and the stimulus spectrum displaying window
