EEG CAP SKIN
EEG CAP PROFESSIONAL

At this step, the priorities are to obtain measurements with a large number of EEG channels, with high coverture of the brain (high density), and with very high resolution and accuracy.

Phase 1 - Exploratory research phase: use in-lab research technologies (wet-EEG caps) to understand human behavior in controlled situations.

EEG CAP PROFESSIONAL

The main purpose of dry technology is to address real-world environments or professional products or services while the semidry EEG capР’В is developed for more exploratory research settings.Р”Р„n easy way to fit both wet and dry-based electrodes EEGР’В in a general research pipeline is: They usually have an electrode system with a higher number of electrode locations, higher head coverage, and better signal quality. Wet EEG electrodes, on the other hand, can be used to record EEG signals in most situations, but they are more research-oriented than dry electrodes. In both cases, the advantage is a quick setup, self-application, up to an 8-hour usage window, and cleanliness for the user ( Dey et al, 2019). Others use a similar concept to create humidity by using highly absorbable porous sponges that are dampened with regular tap water.

EEG CAP SKIN

Some semi-dry electrodes release a small amount of saline solution with the assistance of capillary force through porous ceramic pillars, eliminating the need of skin preparation and gel application (Hua et al.

2019 Wang et al., 2016 Nijholt, 2019), also known as water-based EEG caps, are a novel subgroup of wet-EEG headsets that aim to overcome the drawbacks of current wet and dry electrodes by using tap water within an absorbent material to fill the gap between the sensor and the skin. Semi-dry EEG capsР’В ( Dey et al, 2019 Hua et al. They need instruments like syringes to place the substance between the electrode and the skin, increasing the maintenance cost. They need a substance to be placed between the electrode and the skin which requires some hair cleaning and stronger hygienic procedures for the equipment.Р”Р„brasion of the skin is sometimes required, which is an uncomfortable process for the participant. The advantage of wet electrodes is that they have a better signal to noise ratio than dry electrodes, and therefore require simpler layers in the amplifier devices (easy to design and less expensive). Useful for long recordings or protocols that require movement. Gel viscosity allows it to be used in more dense electrode configurations, but the gel dries over time and it is not recommended for long recordings (i.e.

Liquid: These substances reach the skin easily, but they can spread and create unwanted bridges between electrodes.

Components of the solution (Saline or Non-saline): The saline solution in the gel improves the conductivity, reducing the skin-electrode impedance, but can cause discomfort if the skin has been abraded before gel application.

The main features of the solution are components and viscosity. Gel is then applied with a syringe, usually via a hole in the electrode. After that, an EEG electrode cap with electrodesР’В (small metal discs)Р’В is placed on the head or the electrodes are pasted with collodion to the scalp. Sometimes before using these electrodes, the skin is degreased and abraded to improve the contact quality. They require the application of a highly conductive electrolytic substance (electro gel or EEG gel) between the scalp and the electrode to obtain good contact and reduce the impedance of the skin-electrode interface. Gel and saline electrodes have been the most frequently used sensors for measuring EEG signals in the recent past. The fact that they require an electrolytic substance to improve the conductivity between the sensor and the scalp has a very important impact on the headset usability and comfort, and thus, on the final user experience and possible applications.

Gel, semi-dry, and saline EEG systems are usually referred to as wet-EEG. Semi-dry EEG or Water-based EEG: tap water humidity / adaptable disposal.Get more info about dry EEG systems here. Dry electrodes EEG systems: no substance.The main difference between EEG systems is the type of electrolytic substance used to improve the conductivity between the surface electrodes attached and the scalp ( Liao 2012), part of the EEG sensory layer or EEG cap ( more info here):

Eeg cap