EEG electrode adhesives

EEG testing over several days involves glueing electrodes to the scalp. Due to the strength and odours of common electrode adhesives, individuals often describe the experience of attaching and removing electrodes as unpleasant.

Up until recently, collodion glue was considered the universal standard adhesive used by hospitals around the world for long-term or multi-day EEG testing.

Today, new technologies that directly address the poor patient experiences associated with collodion exist. Seer Medical’s WaterTabs®, for example, are a gel-composition adhesive that is both strong and easily removed under running water. You can learn more about them further down on this page.

What is collodion?

Collodion is an extremely strong and durable glue used by many hospitals for long-term EEG testing . Its strength is intentional — for long-term EEGs, electrodes must be stuck on tight enough to withstand many kinds of movements, especially movement during sleep. Collodion also has a high resistance to moisture, so it is water-resistant and sweat will not affect collodion’s grip on the scalp.

How do you remove collodion glue?

Collodion is an ether-based glue, which means that it can only be removed with a solvent like acetone. Removal can take some time and some people find it very uncomfortable both physically and because of the smell of the acetone. If not removed properly, the glue will remain on the scalp, causing additional irritation. Even after proper removal, some small amounts may remain in strands of hair.

Are there alternatives to collodion?

The standard glue hospitals and other services around the world use is collodion. Since 2021, WaterTabs* have existed through Seer Medical as an alternative EEG electrode adhesive.

WaterTabs are an odourless gel-like glue that Seer Medical uses to secure electrodes to the scalp for multi-day EEG testing. They were designed to minimise the irritation and discomfort typically associated with collodion whilst maintaining strong signal quality for accurate EEG reporting.

While WaterTabs are used for the majority of people who are monitored by Seer Medical, WaterTabs are not appropriate for all. For people with excessive sweating, some people with intellectual disabilities, and people with baldness, collodion may be advised.

• [Download] WaterTabs removal process and aftercare recommendations.

How do WaterTabs compare with collodion glue?

Collodion (ether-based glue)	WaterTabs (water-based composition)
Adhere for 7 to 10 days.
Vapours from collodion may cause respiratory irritation.	Bacteriostatic and odourless gel minimises irritation and discomfort.
Electrode removal can take up to an hour in clinic.	Patients can remove electrodes at home in as little as 15 minutes.
Can only be removed with strong solvents that are harsh on the skin and may also cause respiratory irritation.	WaterTabs dissolve in warm water enabling a more comfortable electrode removal in the shower at the study’s conclusion.
Can remain within the hair for weeks after removal, sometimes causing irritation and skin abrasions.