An electroencephalogram (EEG) is a recording of brain activity. During this painless test, small sensors are attached to the scalp to pick up the electrical signals produced by the brain. These signals are recorded by a machine and are looked at by a doctor. The EEG procedure is usually carried out by a highly trained specialist, called a clinical neurophysiologist, during a short visit to hospital. An EEG can be used to help diagnose and monitor a number of conditions affecting the brain. It may help identify the cause of certain symptoms – such as seizures (fits) or memory problems – or find out more about a condition you've already been diagnosed with. The main use of an EEG is to detect and investigate epilepsy, a condition that causes repeated seizures. An EEG will help your doctor identify the type of epilepsy you have, what may be triggering your seizures and how best to treat you. Less often, an EEG may be used to investigate other problems, such as: dementia head injury and concussion brain tumours encephalitis (brain inflammation) sleep disorders, such as sleep apnoea. Your appointment letter will mention anything you need to do to prepare for the test. Unless told otherwise, you can usually eat and drink beforehand and continue to take all your normal medication. To help the sensors stick to your scalp more easily, you should make sure your hair is clean and dry before arriving for your appointment, and avoid using products such as hair gel and wax. You might want to bring a hairbrush or comb with you, as your hair may be a bit messy when the test is finished. Some people bring a hat to cover their hair until they can wash it at home afterwards. How an EEG is carried out There are several different ways an EEG recording can be taken. The clinical neurophysiologist will explain the procedure to you and can answer any questions you have. You'll also be asked whether you consent to treatment for the various parts of the test to be carried out. This may include video consent for some EEGs. Before the test starts, your scalp will be cleaned and about 20 small sensors called electrodes will be attached using a special glue or paste. These are connected by wires to an EEG recording machine. Routine EEG recordings usually take 20 to 40 minutes, although a typical appointment will last about an hour, including some preparation time at the beginning and some time at the end. Other types of EEG recording may take longer. Types of EEG Routine EEG A routine EEG recording lasts for about 20 to 40 minutes. During the test, you'll be asked to rest quietly. You will usually be asked to open or close your eyes from time to time. In most cases, you'll also be asked to breathe in and out deeply (called hyperventilation) for a few minutes.

1. Electroencephalography
(EEG)
By
Nadia hassan
Ph.D. in medical physics
Mohammed sameer
New-route Ph.d. in MEDICAL IMMUNOLOGY/
SPECIALITY IN clinical AUTOIMMUNity
& stem cell therapy
1st stg / Hammurabi college of Medcine
2024

2. What is an EEG ?
An electro-encephalo-gram (EEG) is a test used to evaluate the electrical activity in
the brain. It can help detect potential problems with brain cell communication.
- An EEG tracks and records brain wave patterns.
- Small flat metal discs called electrodes are attached to the scalp with wires.
- The electrodes analyze the electrical impulses in the brain and send signals
to a computer that records the results.
- EEG used extensively in neuroscience, cognitive science, cognitive psychology,
neurolinguistics, and psycho-physio-logical research, as well as to study human
functions

4. Continuous EEG recording

6. Comparison of EEG bands

8. Greek alphabet:
24

9. History of EEG
• 1875, Richard Caton observed the EEG from the exposed brains of rabbits
and monkeys.
• In 1912, Russian physiologist, Vladimir Vladimirovich Pravdich-Neminsky
published the first animal EEG and the evoked potential of the mammalian
(dog).
• In 1914, Napoleon Cybulski and Jelenska-Macieszyna photographed EEG-
recordings of experimentally induced seizures.
• In 1924, Hans Berger used his ordinary radio equipment to amplify the
brain's electrical activity measured on the scalp.
• In 1934, Adrian and Matthews verified concept of “human brain waves” and
identified regular oscillations around 10 to 12 Hz which they termed “alpha
rhythm”.

10. Why measure EEG
The greatest advantage of EEG is its temporal resolution.
EEG can determine the relative strengths and positions of electrical activity in
different brain regions.
According to R. Bickford (1987) research and clinical applications of the EEG in
humans and animals are used to:
(1) Monitor alertness, coma and brain death.
(2) Locate areas of damage following head injury, stroke, tumor, etc.
(3) Test afferent pathways (by evoked potentials).
(4) Monitor cognitive engagement (alpha rhythm).
(5) Produce biofeedback situations, alpha, etc.

11. (1) Monitor alertness, coma and brain death;
(2) Locate areas of damage following head injury, stroke, tumor, etc.;
(3) Test afferent pathways (by evoked potentials);
(4) Monitor cognitive engagement (alpha rhythm);
(5) Produce biofeedback situations, alpha, etc.;
(6) Control anesthesia depth (“servo anesthesia”).
(7) Investigate epilepsy and locate seizure origin.
(8) Test epilepsy drug effects.
(9) Assist in experimental cortical excision of epileptic focus.
(10) Monitor human and animal brain development.
(11) Test drugs for convulsive effects.
(12) Investigate sleep disorder and physiology.

12. Advantages of EEG
1- Low cost & readily repeatable.
2- Provides some spatial or localization information.
3- Though it is measure of brain function, it supplements neuroimaging
studies.
4- It provides direct evidence of epileptic abnormality.
EEG Pros & Cons

13. Disadvantages of EEG
1- Low spatial resolution on scalp.
2- Determines neural activity poorly below the upper layers of brain.
3- Long time to connect subject with the EEG machine (20-30 min).
4- It detects cortical dysfunction but rarely discloses its etiology.
5- Small or deep lesions might not produce EEG abnormality.
6- Influenced by state of alertness, hypo-glycaemia, drugs.

14. YT Ref Vids
1. 2-Minute Neuroscience: Electroencephalography (EEG)
https://www.youtube.com/watch?v=tZcKT4l_JZk
2. Electroencephalography (EEG) | How EEG test works? | What conditions can an EEG diagnose?
| Animated
https://www.youtube.com/watch?v=T7MKlPYiL48
3.What to Expect During Your Stay in the Epilepsy Monitoring Unit (EMU)
https://www.youtube.com/watch?v=bQqJPFVfMPY
4. Epilepsy With Normal EEG and MRI Brain?
https://www.youtube.com/watch?v=QR0y-JeWQAM
5. How does an MRI machine work?
https://www.youtube.com/watch?v=75_xWBwBB9g

15. Regards