Dry Electrode Guide

Dry electrodes types

Mentalab currently offers three types of dry electrodes.

Flat electrodes

For electrode positions not covered by hair (e.g. on the forehead, mastoid…), our flat electrodes ensure optimal skin contact and comfort.

Brush electrodes

For areas covered in hair, we recommend using brush electrodes. Their flexible pins penetrate most hair types and establish good contact with the scalp.

XL brush electrodes

For very dense and curly hair types, we recommend using our XL brush electrodes for increased hair penetration.

Snap electrodes

Our clip cables also work well with disposable “stick ’n’ peel” (or, “snap”) electrodes. Snap electrodes are commonly used in EOG, ECG, and EMG paradigms, alongside dry EEG, or to ensure a stable reference electrode (for areas not covered in hair).

Summary table

These types of electrodes are interchangeable, but we recommend following these suggestions for maximum comfort and data quality:

Position	Electrode Type
No hair	Flat
Some hair	Brush
Very dense hair	Brush XL
EMG/ECG/EOG	Snap

Before attaching dry electrodes

If you are not using gel, but still want to ensure stable data transmission and lower impedances, choose a position free of hair for the unipolar reference. Common locations are: the mastoid behind the ear, tip of the nose, earlobe, forehead.

Before applying any electrodes to bare-skin, it is a good idea to clean the site with some abrasive gel. We also recommended spraying ethanol onto each dry electrode before putting them on the cap. Both steps help lower the impedance values and stabilize the signal, without leaving residues on the skin.

To reduce motion artifacts, it is best to thread the cables through the larger holes in the EEG cap. Do ensure that there is no tension on the cables when connecting the dry electrodes and the amplifier, as this can lead to the clips disconnecting. Try repositioning the amplifier to alleviate cable tension if needed.

Connecting cables to dry electrodes

We recommend fully preparing the cap before putting it on the participant. This saves the participant time and reduces discomfort.

After threading the cables through the cap holes, place a dry electrode on the inside of the cap at the chosen position. Push the electrode knob through the cap’s little hole. Connect the clip cable to the knob on the outside of the cap and tighten. Repeat for remaining electrodes.

Alternatively, you can connect the cables while the participant wears the cap. To do this, carefully lift the cap at the chosen position, and place the electrode directly underneath. The electrode knob should be sticking out, so that you can attach the clip cable to it on the outside. Repeat for the remaining electrodes.

Ensuring good skin contact

For flat reference electrodes, it can be a good idea to connect the electrode directly to the clip, and tuck it under the cap. This is particularly true if you choose to place the electrode at the mastoid.

For brush electrodes, be sure that the pins reach the scalp through the hair. Pinch the clip, and wiggle it around (side to side, or in circular motion) until the bristles have found their way through the hair and are touching the scalp. Participants should not feel discomfort at any point.

Dry electrode impedances

Achieving low impedances with dry electrodes can be challenging.

For more guidance on minimizing impedances, please have a read of our Improving Impedances page.

After recording with dry electrodes

1. Remove the cap from the participant’s head, before removing all electrodes from the cap.
2. Detach the electrode cable from the Explore amplifier carefully by pressing down on the connector’s click-lock. Do not pull on the cables themselves.
3. Wash the cap with regular soap and water. If needed, disinfect with alcohol. For more details, see our page on Cleaning, Disinfecting, and Storing Mentalab Hardware.
4. Clean the electrodes under running water. Use cotton pads or a soft brush to remove residue between pins if needed. Disinfect with Isopropanol. Be careful not to scratch the metal, and do not to get water on the cable connector.
5. Let cap and electrodes air dry.
6. Turn off and charge your Explore amplifier before your next recording.

Troubleshooting

If you have any trouble or questions while setting up your dry EEG equipment, please do not hesitate to contact our team. We are always happy to assist: support@mentalab.com and have a Troubleshooting page for reference.