User guide
ELI
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ECH001XN111-A4 – 07/2022
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Measurement on ECHOSOFT
6.1 Evoked potential modul (ABR, ECochG et VEMP)
6.1.9
cVEMP muscular contraction level
The cVEMP rejection is based on the contraction of the sternocleidomastoid muscle (SCM) and is therefore dependent
on the patient. It is necessary to adjust it at each measurement.
The gauge at the bottom left of the screen shows the pa-
tient's muscle contraction level. The contraction zone
(in green) indicates the range of muscle contraction
(µV) considered correct for data acquisition. If the con-
traction level is outside this range, the signal is rejected.
When the patient is at rest, the gauge should be red and
should not move significantly from 0 µVolt.
When the patient goes into contraction, the gauge
should increase and turn green when it reaches the con-
traction zone. This zone can be adjusted manually (by
placing the mouse cursor over it) or determined by the
automatic calibration process.
The automatic method allows, in a first phase, to measure the muscular activity of the patient at rest. In a second
phase, the patient must position himself in dorsal decubitus, his activity, when he contracts the SCM muscle, is then
evaluated. This determines the ideal contraction level for good quality measurements. Even if the operator wishes to make
the settings manually, it is advisable to perform an automatic calibration first
Automatic calibration process:
1 – Select the ear on which you will start the measure-
ment
2 – Check if impedances are good
3 – Click on the button « Automatic calibration »
4 – The software starts with « rest calibration », ask the patient to relax and then click on « Start »
5 – When it reaches 100%, the software will wait for a « Contracted calibration», ask the patient to position himself
in supine position and then click on « Start »
6 - When the advance reaches 100%, you can tell the patient to release the contraction.
If the software does not display any errors, you can proceed with the measurements
If the software indicates "The contraction is too low",
this means that the difference in muscle activity be-
tween the resting position and the supine position is not
sufficient to perform the measurements correctly.
Make sure that the patient is seated and positioned correctly in the supine position. Restart the calibration procedure
from the beginning.
Valid contraction area
Valid contraction area
