**2. Registration of bioelectrical activity in a routine study**

#### **Important!**

EEG registration begins with the procedure for checking the device for electrical safety!

Make sure that the instrument is connected to the network (control computer). Wires (especially mains power wires) do not have visible damage, which are not located near water or heat sources.

Carrying out functional stress tests may be associated with the risk of developing an epileptic seizure or other paroxysmal condition. Therefore, the specialist conducting the study must have the skills to provide resuscitation and also be able to call the resuscitation team.

#### **2.1 Patient preparation**

The patient comes to the study in a calm state with a clean head. Best of all, in the first half of the day, in order to avoid the consequences of psycho-emotional impact.

#### **2.2 Start of the study**

The patient is connected using an electrode interface (cap). It is necessary to make sure that the cap is clean and dry, and the helmet material and wires do not have visible damage.

Installation of electrodes is carried out by means of the international layout of electrodes "10-20."

Installation of reference (ear) electrodes is carried out on the earlobes A1—left lobe and A2—right lobe using electrodes—clothespins.

If it is impossible to install ear electrodes (there are no clothespins in the packing or otherwise), reference electrodes are installed on the mastoid processes A1—left mastoid process and A2—right mastoid process.

After connecting the patient to the device, the photostimulator is installed at a distance of 20 cm from the eyes and the direction of the light flux is checked.

#### **2.3 Next, we move on to working with the program**

1.Fill out the patient card

We enter data into the card, including full name, age, and gender

2.Checking the installation of the current installation

Most often, the current editing of the recording is set automatically, but before examining, you need to make sure that the program settings have not changed.

3.Check the write speed

Write speed should be set to 30 mm per 1 second

4.Checking the amplitude sweep

Amplitude sweep set to 7 μV

5.Checking the settings of filtering values

The low-frequency limit is set to 0.5 Hz

The high end is set to 35 for normal exploration and 70 for advanced.

After checking the recording parameters, we start monitoring—a mode in which the device is turned on, but no data are written to the disk.

In monitoring mode, we check the characteristics of the curves and proceed to the impedance test.

#### 6. Impedance test

The subelectrode resistance (impedance) shows the correct installation of the electrode and characterizes the contact of the electrode with the scalp. The impedance value must not exceed 10 kOm. At high impedance values, it is necessary to check the contact of the electrodes with the scalp, if necessary, remove the hair that has fallen under the electrode, add an electrically conductive gel, or thoroughly degrease the skin with an alcohol-containing solution and a cotton swab.

After stabilization of the impedance values (should be equal under all electrodes), we start recording with research.

7.Study recording

The study recording mode differs from monitoring in that the data are saved to the computer's hard drive. Recording is the main survey mode!

During the study, the patient is presented with various functional tests, which, for ease of understanding, are combined into a single-study scenario.
