Maico MB 11 BERAphone Operation Manual page 54

Figure 34
The impedance values measured for Vertex / GND) and Mastoid / GND lines are
shown in the status line in the lower left corner at the screen.
In the case of a red light, the impedance must be corrected. This can be done by
repeating the preparation with the electrode gel to lower the impedance of the skin.
In some cases, it may take a few minutes for the electrode gel to soak into the skin
and take effect.
The impedance can sometimes be improved by shifting the position of the electrode at that site
slightly, making sure to be in contact with area of the skin which was prepared with the electrode.
If these measures have been attempted and impedance remains poor, then use of a
more abrasive skin preparation product, such as Nuprep
pad, may be needed. Poor impedance can occur if lotion has been applied to the
baby's skin.
The impedance test is passed when all three electrodes show green or yellow for seven
seconds. After passing the impedance test, the measurement starts and the
impedance indicator lights change into the signal quality light or EEG view.
The Signal Quality Control
The signal quality in the screening mode is determined by the ratio of artifact and
accepted signals. Artifacts are big potentials caused by electrical noise, muscle activity
or muscle tension. Signal quality depends strongly on the correct position of the
electrodes and on electrical noise in the surrounding environment. Excessive periods
of artifact can prolong the test time and may increase the chance of a REFER result.
Figure 36
8100496 Rev. 6
Operation Manual MB 11 BERAphone
Figure 35
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Figure 37
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or an electrode skin prep
23/10/2019