Électronique du Mazet ECHODIA ELIOS, Руководство пользователя

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User guide
ELI O S
ECH001XN111-A4 – 07/2022
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Handheld mode measurement 4.6 Shift-OAE
4.6.2.1 OAE probe self calibration
When the measurement begins, a series of calibrations are performed automatically to determine if the measurement
conditions are optimal to obtain usable results. In this context, the system may asks the user to make choices in order to
adjust the measurement parameters as best as possible:
•
"Low signal . Check leak. Continue?" : The signals F1 and F2 and are too low compared to their set value (at
least 20dB too low). This may be due to the wrong positioning of the probe, more precisely a sealing problem
between the probe plug and the ear canal. It is advised to click on “No”, reposition the probe and restart the meas-
ure. However, if you are sure of the probe positioning, it is possible to continue by clicking “Yes”.
•
"Too much signal, Check eartip. Continue?" : The signals F1 and F2 and are too strong compared to their set
value (at least 20dB too strong). This may be due to the wrong positioning of the probe, more precisely a plug's
probe pushed too deep in the ear canal. Is is advised to click on “No”, reposition the probe and restart the meas-
ure. However, if you are sure of the probe’s positioning, it is possible to continue by clicking “Yes”.
•
"Too many rejection! Probe has moved or the patient is tense. Retry?" : The recorded signal has too many
fluctuations, this scenario can occur if the patient speaks, is too nervous or moves during the calibration phase.
You can restart this phase by clicking “Yes”.
•
"Too much noise! Probe gets out or noisy room. Continue?" : The average noise of the measure is too high,
the signal distortion product may not get out enough of the noise. Click on “No”, verify if the patient is not too
nervous and if the test environment is not too noisy. It is possible to continue by clicking “Yes”.
•
"Low Signal! Would you automatically adjust measurement parameters?" : The distortion product signal is
too low to be reliable. Click “Yes”, the system will change the measurement parameters (Power and / or number
of averages) to try to get a decent signal strength. Click on “No”, you will be redirected to the window configura-
tion.
•
"The signal is an artifact. Change the test frequency and retry." : The system detects that the distortion prod-
uct signal is an artifact, it is most often due to the resonance frequency of the ear canal cavity. To deal with this
issue, it is often sufficient to change the stimulation frequency of a few hertz to no longer be in frequencies reso-
nance of the patient's ear canal. Click “Ok”, you will be redirected to the configuration screen, change the fre-
quency of ten or twenty hertz then restart the measurement.
•
"Low signal! Artifact test is impossible. Continue?": To perform the artifact test, the device scan distortion
products at different frequencies, it is possible that for some patients, the products distortions do not exist at these
frequencies, in this case the artifact test could not be done. Nevertheless you can continue the measurement by
clicking on “Yes”. You can attempt to solve the problem by clicking on “No” and change the stimulation fre-
quency of a few hertz.
4.6.2.2 Mesure
A progression bar informs you of the state of progress of a point. When the progression bar ends, the system adds a
point to the graph. This graph contains several kind of information:
•
The phase curve represents the measured phase shift value included between ±180°. The color of each point on
the curve depends on the position of the patient.
1. The index given above a point is the phase shift value in degrees.
2. The index, indicated in white below a point, is the ratio between the effective signal and the average noise in
dB (S/N). To validate a point, this value must be greater than 6dB.
•
To help you to analyze a point, in the lower part of the graph, the system plots two solid curves.
Patient position
Rejection level setting
Rejection indicator
Phase curve
Progress bar
Min / Max signals