As with most things, getting the basics right can make all the difference to the success of your testing. When it comes to electrophysiological testing, ensuring that the electrodes are secure and have low impedances is crucial to effective and efficient testing.
- Use an abrasive preparation gel to ensure that the top layer of skin is cleaned.
- Use an alcohol-wipe or similar cleaning agent to clean newborn skin, especially if the skin is greasy or oily.
- If the skin is dry or sensitive, it may be best to use a soft dry cloth since alcohol can dry out the skin.
- After cleaning with alcohol wipes, ensure that the skin is completely dry before applying conductive gel and electrodes.Otherwise, electrode impedances may be slightly higher.
- Use a small amount of conductive electrode gel to improve impedances, if required.
Mounting the electrodes:
- Mount the disposable electrode by pressing down to ensure maximum adhesion. Note: some disposable electrodes are pre-gelled. Do not press in the middle of these as the gel will then spread to the adhesive outer edge, resulting in poor adhesion to the skin.
- 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 (≤ 1 kOhm). Recommended impedance levels are ≤3 kOhms and balanced.
- For reusable electrodes, always apply a conductive electrode gel or paste before mounting.
- Medical tape can be used to hold the reusable electrode in place.
- If the impedance remains too high, you can always remove the electrode and rub/abrade the site again.
Find more hints on how to best prepare the skin and mount electrodes for ABR, automated ABR and ASSR in our guick guide, Some hints to improve ABR/ABRIS/ASSR recordings