F.A.Q

Instruction and requirements for the EEG specialist technician

The person who conducts the recording must absolutely be a trained technician, educated in EEG and EEG recording techniques.

For technically optimum recording quality is necessary to meet the following requirements:

1. It is imperative to choose the correct size of the COMBY EEG CAP by measuring the circumference of the patient's head cap with attached measuring tape.
2. Before starting the recording, make sure that the cap is completely clean and dry. DO NOT USE the cap immediately after washing it, but allow the cap to dry completely. We recommend leaving the cap to dry overnight.
3. Visually inspect the cap for the following issues: check the cap for any physical damages or changes, such as broken rubbers, broken electrodes, broken wires, re-positioned electrodes from previous recordings; check if the cap is clean and if the electrodes are clean and free from any residual gel; check the cap for any other physical damages.
4. Before the first recording or after a long break, the electrodes must be cleaned with cotton wool soaked in clean distilled water or physiologic saline. It is also necessary to regularly maintain the cap clean according our maintenance instruction.
5. Before fitting the cap onto the head conduct the “check impedance” procedure.
6. Insure that the electrodes are on the right positions according to 10-20 or 10-10 International system, depending on the number of electrodes on the cap.

The International 10-20 system is the standard method used for electrode placement on the scalp during EEG recordings. The system ensures consistent and reproducible electrode positioning across all patients and sessions.

Procedure for correct electrode placement:

1. Measure the distance from the nasion (bridge of the nose) to the inion (bump at the back of the skull) along the midline of the head.
2. Measure the distance between the left and right pre-auricular points (just in front of each ear) across the top of the head.
3. The intersection of these two measurements determines the Cz (vertex) position.
4. Electrode positions are placed at intervals of 10% and 20% of these measured distances, hence the name "10-20 system."
5. COMBY EEG CAPs are pre-configured with color-coded electrode positions according to the 10-20 system, which greatly simplifies the placement process.
6. Each electrode position label identifies its location: the letter indicates the brain region (F=Frontal, C=Central, P=Parietal, O=Occipital, T=Temporal), and odd numbers indicate the left hemisphere while even numbers indicate the right.

By choosing the correct COMBY EEG CAP size (see FAQ #3), the electrodes will automatically be positioned according to the 10-20 International System, ensuring accurate and consistent recordings.

Choosing the correct cap size is critical for accurate EEG recordings. An improperly sized cap will result in misaligned electrode positions, poor electrode contact, and unreliable data.

Available sizes for Adults:

• Size S (Small) — Head circumference: 50–54 cm
• Size M (Medium) — Head circumference: 54–58 cm
• Size L (Large) — Head circumference: 58–62 cm

Available sizes for Children:

• Child S — Head circumference: 44–48 cm
• Child M — Head circumference: 48–52 cm
• Child L — Head circumference: 52–56 cm

How to measure: Use the measuring tape included with the COMBY EEG CAP. Wrap it around the head at the widest point, passing just above the eyebrows at the front and over the most prominent part of the occiput at the back. Note the circumference in centimeters and select the corresponding cap size.

Important: Always measure the patient's head before each session. Do not assume a size based on appearance. A proper fit ensures that all electrode positions align correctly with the International 10-20 system.

1. Wash the hair with shampoo.
2. Do not use hair preparation: gel, hair spray, hair oil, foam...
3. Do not come to EEG with wet hair.
4. Do eat before EEG (possibility of hypoglycemia).

COMBY EEG CAP is supplied non-sterile, and is intended for re-usage.

After completing the recording, wash the COMBY EEG CAP in warm water with a light solution of liquid disinfectant detergent (such as Ivory or similar).

With a cotton stick sodden in the distilled water, clean any residual layer of gel on each electrode. If absolutely necessary you can use a soft toothbrush to clean the residual gel.

Rinse and dry the cap with the towel (cotton or paper) and leave to dry for the next recording, or if necessary to use immediately, dry the cap with a low heat hair dryer on a distance of min. 20 cm.

Pay attention to the residual layer of gel which could dry in the electrodes, because it creates high resistance layer that prevents the recording.

In the procedure of disinfection please use alcohol based medical disinfectant. Do not use disinfectants containing any chloride or sulphor. Disinfection process should be carried out according to disinfectant's manufacturer instructions.

Please consult the video IFU as well. https://youtu.be/-e6yP_POUQE

WARNING: It is not allowed to use abrasive or sharp objects to clean the electrodes as this may result in permanent destruction of the electrodes! Usage of strong disinfectant significantly shortens the COMBY EEG CAP lifetime! Contact gel should be applied with standard medical syringe and plastic tip applicator! Contact paste should be applied with flat plastic spatula.