D-0103906-D – 2019/03 Page 1 of 5
Quick Guide
Some hints to improve ABR / ABRIS / ASSR
recordings
Several things can influence the results obtained during ABR / ABRIS / ASSR testing. In this guide, some hints
for improved recordings will be described. All the suggestions listed below can be applied to the ABR, ABRIS and
ASSR module.
Skin Preparation and Electrodes
1. Preparing the skin
Always use an abrasive preparation gel (e.g., NuPrep) to ensure that the top layer of skin (epidermis) is cleaned
and oil is removed. The skin may become a little red after an appropriate preparation, and you should aim to get
impedances below 3kOhm.
Note Be careful not to damage the skin.
Neonates Some clinicians use only alcohol wipes/pads to remove vernix prior to ABR recording on neonates
(age 0-3 months). A disinfectant agent such as alcohol can also be used for preparing the skin of neonates.
Preparation instructions: Remove any oil/lotion/vernix from the contact point on patient’s head. Wipe all
preparation gel off with an alcohol wipe/pad or a soft dry non-stick cloth (e.g., gauze).
- For sensitive/allergic skin, it may be best to use only a soft dry cloth since alcohol can dry out the skin.
If the patient suffers from any known allergies e.g., perfume, pay extra attention to the use of disinfectant
agents
- Since alcohol may take time to dry, impedances may be slightly higher when using alcohol. Make sure
that the alcohol is completely dry before applying conductive gel and electrodes
- Some clinicians prefer not to use alcohol pads/disinfectant agents, but remove the preparation gel with a
dry non-stick cloth (e.g., gauze)
- If the patient’s skin is dry or you are obtaining high impedances, apply a small amount of conductive
gel/paste to the skin prior to connecting the surface electrode. This will help to rehydrate the skin and to
lower impedances
2. Mounting the electrodes
Always prepare the skin prior to mounting either disposable or reusable electrodes.
Some disposable electrodes are pre-gelled (e.g., PEG15), and no further gel is required.
Note When mounting pre-gelled disposable electrodes (e.g., PEG15), do not press in the middle of the electrode
as gel to be dispersed to the adhesive outer edge causing the electrode to loosen from the skin, causing very
high impedances during testing.
- Mount the disposable electrode by pressing down around the adhesive outer edge
- If you gently pull on the electrode a few seconds after application, the electrode should remain tightly
adhered to the skin. This should ensure very low impedances (≤ 1kOhm)
- Recommended impedance are below or equal to 3kOhms and balanced (e.g., all electrodes should
have similar impedance values within 2kOhms)
Reusable electrodes are expected to have higher impedance than the disposable electrodes.
- For reusable electrodes, it should be possible to achieve impedances in the range of 1-5kOhms
- Always apply a conductive electrode gel/paste (e.g., 10-20 paste) to all reusable electrodes before
mounting
- Use medical tape (e.g., micropore) to hold the reusable electrode cups in place on the skin
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