**5.1 Continued EEG study**

The purpose of the study: to identify a possible pathological response to functional loads, if there is a suspicion of the likelihood of developing a seizure, but no pathology is detected on a routine examination, but there are suspicions of the development of such.

The main objective of the study is to exclude the possibility of developing a seizure in workers of complex industries.

The study is based on repeated functional stress tests for a long time (up to 3 hours)

#### **5.2 Study scenario**

Background recording 5 min

Opening eyes—1 min. Closing eyes – 1 min.

Background recording—3 min.

Test with photostimulation (rhythmic light flashes are presented with the help of a photostimulator):

• 1 Hz—10 sec.

◦ Break 5 sec

• 2 Hz—10 sec.

◦ Break 5 sec

	- Break 5 sec

◦ Break 5 sec

	- Break 5 sec

Background recording—3 min. Opening eyes—1 min. Closing eyes—1 min. Background recording 1 min. Hyperventilation—3 min. Background recording—5 min. Opening eyes—1 min. Closing eyes—1 min. Background recording 20 min. Study repetition (up to 6 times) Study Termination

*Practical Recommendations for Conducting an EEG Study in a Neurophysiological Laboratory DOI: http://dx.doi.org/10.5772/intechopen.108879*

#### **Important!**

When pathological activity appears in the record, the study is terminated as the main goal is achieved and the task is completed.

After the studies, the recording stops and the data are saved, which are transferred for analysis to the doctor, who forms the medical report.

#### **5.3 VideoEEG monitoring from 4 hours (in children) to 9–12 hours in adults)**

**Purpose of the study:** to evaluate changes in bioelectrical activity under conditions of a decrease in external stimuli and changes in the characteristics of the bioelectrical activity of the brain caused by a change in the phases of physiological sleep).

#### **5.4 Patient preparation**

The patient comes to the study in a calm state with a clean head. It is best that he does not attend work on the day of the study.

With him, the patient has pajamas or a tracksuit to change into.

Before the study, the patient is explained that he will be filmed by a video camera throughout the study and he will be in bed without a blanket.

#### **Important!**

The patient should not take sleeping pills for the onset of sleep, but the patient does not stop taking basic drugs (especially antiepileptic ones!)!

Conducting research

The patient is connected to the device as well as for routine examination; however, the use of electrically conductive gels is inappropriate for studies lasting more than 4 hours. When planning a long study, it is better to use a special conductive paste.

#### **Important!**

There is no need to require the subject to be in a state of sleep. A person can be in a state of passive relaxed wakefulness or perform normal activities. The main condition is constant video recording!

#### **Important!**

Functional stress tests, including opening-closing of the eyes, rhythmic photostimulation, and hyperventilation during sleep monitoring are NOT PERFORMED! Due to the possible disruption of the process of falling asleep.

All functional stress tests are carried out at the stage of a routine examination and an extended EEG examination!

#### **During night sleep monitoring, the following events are noted:**

1.Time of arrival of the patient in the ward

2.Bedtime

3.Light off time

4.Time of onset of sleep

5.Events (woke up, went to the toilet, etc.)

6.Main wake up time

7.Light on time

8.Time when the patient left the room.

After the studies, the recording stops and the data are saved, which are transferred for analysis to the doctor, who forms the medical report.

#### **5.5 Ambulatory EEG monitoring (not always present in EEG laboratories!)**

It is the longest version of the EEG—examination.

Purpose of the study: to establish how changes in the bioelectrical activity of the brain affect the daily life of the subject

The main task: to establish a direct relationship between the development of pathological bioelectrical activity and a violation of the quality of life of the subject.

Ambulatory EEG—monitoring is carried out using special mobile devices similar to ECG monitoring devices (Holter ECG).

The installation of electrodes should imply prolonged contact with the patient's skin; therefore, special electrically conductive collodion-based adhesives are used as a contact medium. The use of standard gels for outpatient EEG monitoring is not suitable, and the use of conductive pastes is possible only within the daily study.

The time of the study is from 1 day to a week.

After installing the electrodes, they are connected to the device. The operator checks the charge of the power sources of the device, checks the fullness of the information storage, and controls the impedance. After these manipulations, the device is fixed on the patient's body, eliminating tension and breakage of the conductors.

The subject is given a form of a diary of observations drawn up in a free form in which he must enter information about his current condition.

#### **Important!**

The main task of long-term EEG examinations is to PROVE THE DIRECT RELATIONSHIP of the functional disorders present in the subject with epileptic changes in bioelectrical activity or to prove the absence of this connection!

A successful examination is only one in which a functional disorder was recorded videographically, which forms the basis of the clinical picture of the disease and a clear connection was established between the fact of its occurrence and the registration of pathological paroxysmal activity on the electroencephalogram!!!

If there is no event registration or there is no direct connection between the clinical manifestations of the disease and changes in the electroencephalogram, the results of VideoEEG monitoring are not conclusive!

#### **5.6 EEG examination in patients with stroke**

Ischemic stroke is a disease that occurs as a result of cerebral infarction and is characterized by the development of persistent focal neurological syndromes of loss of functions, primarily motor.

Therefore, a functional study of the state of the bioelectrical activity of the brain under conditions of motor load is of great interest both in assessing the general condition and in developing rehabilitation measures.

*Practical Recommendations for Conducting an EEG Study in a Neurophysiological Laboratory DOI: http://dx.doi.org/10.5772/intechopen.108879*

**The purpose of the study** was to evaluate changes in the bioelectrical activity of the brain caused by violations of cerebral hemoperfusion and to identify the reactions of the microcirculatory vascular bed under conditions of physical exertion.

#### **5.7 Periodization of ischemic stroke**

1. the most acute period—the first 3 days (with regression of symptoms in the first 24 hours, a transient ischemic attack is diagnosed)

2.acute period—up to 21 days

3.early recovery period—up to 6 months

4.late recovery period—up to 2 years

5.period of residual effects—after 2 years
