Preparations Prior To The Assr Test; Preparations Prior To Testing; Preparation Of The Skin; Placement Of Electrodes - Interacoustics Eclipse Instructions For Use Manual

8.2

Preparations prior to the ASSR test

For obtaining reliable and valid test results it is most important that the patient is well prepared for the test.
8.3

Preparations prior to testing

8.3.1 Preparation of the Skin

Be sure not to apply the following procedure to patients for whom it is inappropriate.
NOTICE
The LBK15 unit is not valid for functional check of ASSR.
The electrode sites must be prepared and cleaned in order to obtain acceptably low skin impedance. For this
purpose, a large variety of electrode pastes can be purchased. Please note that two different types of electrode
paste exist: One which rubs off the outer thin layer of the skin, and another which is an electrically conductive
paste used to adhere reusable electrodes. Only the first type can be used for skin preparation (you can feel the
abrasive nature of this type of paste when rubbing it between your fingers).
A good and thorough job of rubbing the skin with the preparation paste might turn the skin a little red but will
ensure good impedance. Neonates generally do not require excessive abrasion.
Most clinicians prefer to clean off the paste with alcohol wipes. This will also ensure a very clean area well
suited for the adhesive part of the electrode.

8.3.2 Placement of electrodes

After having prepared the skin, place an electrode on each mastoid (blue electrode lead on left side, red on
right side) one at the vertex or hair-line (white electrode lead) and the ground connection (black) can be
placed on the low forehead or side of the forehead. The placement of the ground electrode is not very
critical.
Note that all four electrodes must be positioned.
The electrodes supplied with the unit are single use types, which are already prepared with electrically
conductive paste, so no further preparation is needed.
Note: Positioning of the white electrode at the true vertex will provide waveforms with higher wave
amplitudes. Special electrodes suitable are available for true vertex montage.
If the common and very stable hair-line position procedure is used, move the electrode as close to the hair-
line as possible for best results.

8.3.3 Impedance check

After having attached the electrodes to the patient it is crucial to check if the skin impedance is acceptable.
For best results, impedance at each electrode should be as balanced and as low as possible, preferably 5
kΩ or less.
To check the electrode impedances, click on the IMP button on the Preamplifier.
Turn the dial fully clockwise and then turn it slowly counter clockwise. Each LED will turn from
to as the impedance is found for that specific electrode. The impedance value can be read on the
Preamplifier and must be below 5kΩ and should preferably be approximately the same for all electrodes.
If the impedance of one or more electrodes is too high, you may want to wait for a minute or two, as the gel
on the electrode has a tendency to improve its impedance with the skin over the first couple of minutes.
D-0120578-C – 2019/11
Eclipse – Instructions for Use - US
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