In this article, we will discuss how to choose the right conductive gel for your EEG experiment.
EEG gels are important
Electroencephalography (EEG) is a non-invasive neuroimaging technique that measures the electrical activity of the brain. EEG is widely used in research, clinical settings, and brain-computer interface technology.
To acquire high-quality EEG signals, researchers need to apply a conductive gel to the scalp to reduce impedance and improve signal quality.
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The conductive gel enhances the electrical connection between the electrodes and the scalp and prevents ambient noise from contaminating the EEG signal.
Not all gels are alike
Some people believe that all EEG gels are the same product housed in different packages. This is not true.
Each conductive gel has its own viscosity, drying time, and composition, amongst other things. Choosing the wrong gel can lead to poor signal quality, artifacts, and discomfort for the subject.
If you’re struggling with EEG artifacts, have a look at ways to reduce noise in EEG.
When selecting a gel, be sure to consider these properties.
Viscosity
Viscosity can affect the electrode-skin contact and the drying time.
A highly viscous gel can be challenging to spread evenly over the scalp and can lead to electrode displacement. A gel with low viscosity can be too watery and may dry out too quickly, reducing the quality of the EEG signal.
Therefore, we recommend a conductive EEG gel that has moderate viscosity. It should be easy to apply, spread evenly, and not dry out too quickly.
Composition
EEG gel composition is also important. The most commonly used conductive gels for EEG experiments are water-based and contain a small amount of salt. The salt concentration can affect the conductivity of the gel.
A higher salt concentration in the gel may result in a better quality signal. However, higher salt concentrations can also cause discomfort for the subject. Therefore, try to balance conductivity with comfort.
Availability and dispensing type
There are two more critical factors to consider when choosing your EEG gel: availability and the type of dispenser.
You need a supplier who can provide your gel quickly and efficiently. In short, it needs to be available. Shipping overseas can be costly and time-consuming, so it is better to find a local provider if possible.
Conductive gels come in all kinds of dispensers, including tubes, jars, and syringes. Be sure to choose the dispenser that best suits your experiment.
For instance, with mobile experiments (outside the lab) you may want smaller tubes that you can fit in your pocket. This makes transporting the gel an easy task and ensures that you can apply it quickly without the need for additional equipment.
For lab-based experiments, choose larger jars and syringes. These larger dispensers are more cost-effective and you can use them for longer.
Selecting an EEG gel is a balancing act
Choosing the right conductive gel for EEG experiments is critical if you want to obtain high-quality EEG signals.
Conductive gels have unique characteristics. Be sure to consider availability, type, viscosity, and composition when selecting your EEG gel.
Find a local supplier, choose moderate viscosity with a suitable salt concentration, and ensure that the dispenser type is appropriate for your experimental set-up.
