Eeg (electroencephalo

cns

1. EEG (ELECTROENCEPHALO GRAM) Muhammad Zulfiqar Bin Ramlan 082015100031 Nur Farra Najwa Binti Abdul Azim 082015100035

2. OBJECTIVES At the end of seminar students should be able to What is EEG Indication Contraindication Risk of EEG Preparations Procedure Result interpretation

3. INTRODUCTION Recording of surface electrical activity of brain @ cerebral cortex A test that detects electrical activity in your brain using small , flat metal discs (electrodes) attached to your scalp. Brain cells communicate via electrical impulses and are active all the time, even when sleeping. This activity shows up as wavy lines on an EEG recording. An EEG is one of the main diagnostic tests for epilepsy . An EEG may also play a role in diagnosing other brain disorders.

4. INDICATIONS Can determine changes in brain activity that may be useful in diagnosing brain disorders, especially epilepsy. An eeg can't measure intelligence or detect mental illness. Used to confirm brain death in someone in a persistent coma. A continuous eeg is used to help find the right level of anesthesia for someone in a medically induced coma. An eeg may be helpful for diagnosing or treating the following disorders: Epilepsy or other seizure disorder Brain tumor Head injury Brain dysfunction that may have a variety of causes (encephalopathy) Stroke Inflammation of the brain (encephalitis) Sleep disorders Dementia

5. CONTRAINDICATIONS Only relative contraindications Raised intracranial pressure Recent MRI (<3 month) >6 month not a contraindications Retinal detachment Pheochromocytoma Anesthetic risk Cardiac pacemaker is not a contraindications Thyroid dysfunction should be corrected

6. RISK EEGs are safe and painless. Sometimes seizures are intentionally triggered in people with epilepsy during the test, but appropriate medical care is provided if needed

7. PREPARATIONS To prepare for an EEG: Wash hair the night before or the day of the test. Hair products can make it harder for the sticky patches that hold the electrodes to adhere to your scalp. Avoid anything with caffeine on the day of the test, because caffeine can affect the test results. Take the usual medications unless instructed otherwise. If asked to sleep during the EEG test, the doctor may ask to sleep less or even avoid sleep entirely the night before the EEG.

8. PROCEDURE You’ll be asked to lie down on your back in a reclining chair or on a bed. The technician will measure your head and mark where the electrodes will be placed. These spots are then scrubbed with a special cream that helps the electrodes get a high-quality reading. The technician will put a sticky gel adhesive on 16 to 25 electrodes. They will then be attached to various spots on your scalp .

9. Once the test begins, the electrodes send electrical impulse data from your brain to the recording machine. This machine converts the electrical impulses into visual patterns that can be seen on a screen. These patterns are saved to a computer. The technician may instruct you to do certain things while the test is in progress. They may ask you to lie still, close your eyes, breathe deeply, or look at stimuli (such as a flashing light or a picture). After the test is complete, the technician will remove the electrodes from your scalp.

10. 10-20 SYSTEM The 10-20 System of Electrode Placement is a method used to describe the location of scalp electrodes . Based on the relationship between the location of an electrode and the underlying area of cerebral cortex . Each site has a letter (to identify the lobe) and a number or another letter to identify the hemisphere location. The letters F, T, C, P, and O stand for Frontal, Temporal, Central, Parietal and Occipital. (Note that there is no "central lobe", but this is just used for identification purposes .)

11. Even numbers (2,4,6,8) refer to the right hemisphere and odd numbers (1,3,5,7) refer to the left hemisphere. The z refers to an electrode placed on the midline. Also note that the smaller the number, the closer the position is to the midline. Nasion  - point between the forehead and nose. Inion  - Bump at back of skull. The "10" and "20" refer to the 10% or 20% interelectrode distance

12. RESULT INTERPRETATIONS Gamma Waves These are involved in higher processing tasks as well as cognitive functioning. Frequency range: > 40 Hz Too much: Anxiety, high arousal, stress Too little: depression , learning disabilities Optimal: Binding senses, cognition, information processing, learning, perception, REM sleep Increase gamma waves: Meditation Location : Somatosensory cortex

13. Beta Waves These are known as high frequency low amplitude brain waves that are commonly observed while awake. They are involved in conscious thought, logical thinking, and tend to have a stimulating affect Frequency range: 12 Hz to 40 Hz Too much: Adrenaline, anxiety, high arousal, inability to relax, stress Too little: daydreaming , depression, poor cognition Optimal: Conscious focus, memory, problem solving Increase beta waves: Coffee, energy drinks, various stimulants Location : o n both sides in symmetrical distribution and is most evident frontally

14. Alpha waves This frequency range bridges the gap between our conscious thinking and subconscious mind. It helps us calm down when necessary and promotes feelings of deep relaxation Frequency range: 8 Hz to 12 Hz Too much: Daydreaming, inability to focus, too relaxed Too little: Anxiety, high stress, insomnia Optimal: Relaxation Increase alpha waves: Alcohol, marijuana, relaxants, some antidepressants Location : posterior regions of head, both sides, higher in amplitude on dominant side

15. ALPHA BLOCK When the subject's eyes are closed, the alpha rhythm is generated. As soon as the eyes are open, alpha disappears and is replaced with the beta rhythm. This is called alpha block and may be elicited also by mental activity

16. Theta Waves This particular frequency range is involved in daydreaming and sleep. Theta waves are connected to us experiencing and feeling deep and raw emotions Frequency range: 4 Hz to 8 Hz Too much: depression , hyperactivity, impulsivity, inattentiveness Too little: Anxiety, poor emotional awareness, stress Optimal: Creativity, emotional connection, intuition, relaxation Increase theta waves: Depressants

17. Delta Waves These are the slowest recorded brain waves in human beings. They are found most often in infants as well as young children. As we age, we tend to produce less delta even during deep sleep Frequency range: 0 Hz to 4 Hz Too much: Brain injuries, learning problems, inability to think Too little: Inability to rejuvenate body, inability to revitalize the brain, poor sleep Optimal: Immune system, natural healing, restorative / deep sleep Increase delta waves: Depressants, sleep Location : frontally in adults, posteriorly in children

18. SUMMARY At the end of seminar students should be able to What is EEG Indication Contraindication Risk of EEG Preparations Procedure Result interpretation

19. REFERENCES http://www.mayoclinic.org/tests-procedures/eeg/basics/risks/prc-20014093 http:// www.healthline.com/health/eeg#Procedure5