EEG (electroencephalogram)

a presentation about EEG

1. Electroencephalogram(EEG) Ahmed Nazar mustafa university of duhok/college of medicine

2. A n Introduction into EEG : - *EEG is a medical device for analyzing the electrical activity of the brain. * it can detect Epilepsy or Alzheimer’s diseases. . * used in humans by Hans Berger in 1924 *the general mechanism is picking up the charge of electrical potentials *the neurons are negative (-) when they are at rest and become positive (+) when they synapse   Ahmed Nazar mustafa university of duhok/college of medicine

3. *the EEG can record this change by electrodes *the signals are transferred from the electrodes to the amplifiers because the power of brain signal is very small *then processed signals are shown on a screen or printed on paper *the neurologist can compare them with normal EEG recording *it’s a safe procedure *instructions will be given to the patient before the procedure. Ahmed Nazar mustafa university of duhok /college of medicine

4. Component Of EEG :- 1- Electrodes : Small metal discs usually made of stainless steel, tin, gold or silver covered with a silver chloride coating . Placed on the scalp in special position these position is specified using the international 10/20 system . Each electrode site is labeled with a letter and a number , the letter refer to the area of brain underlying the electrode . Even numbers denote the right side of the head and odd numbers denote the left side of the head . Ahmed Nazar mustafa university of duhok /college of medicine

5. Types of electrode placement :- 1-EEG electrodes placed separately on scalp 2- EEG electrodes mounted as special band on head Ahmed Nazar mustafa university of duhok/college of medicine

6. Component Of EEG …… … . 2- Amplifier : It is an electronic device that increases the power of a signal. It does this by taking energy from a power supply and controlling the output to match the input signal shape but with a larger amplitude. Human brainwave activity is too subtle to read unless the signal is amplified. These units available now usually connect through a USB port and transmit signals to the therapist computer. Older units use a serial interface . Ahmed Nazar mustafa university of duhok/college of medicine

7. Component Of EEG ……. 3- Filters :- The use of filters in recording and displaying EEG data is an indispensable tool in producing interpretable EEG tracings. Without filters, many segments of EEG would be essentially unreadable [ figure at right side ]. The main benefit of filters is that they can appear to “clean up” the EEG tracing, making it easier to interpret and generally more pleasing to the eye. Ahmed Nazar mustafa university of duhok/college of medicine

8. Component Of EEG ……. 4- Writing unit :- The final link between the patient and a legible EEG tracing is the writer. A pen-ink-paper system is employed [ Figure at right ]. The speed of the paper mechanism should include 30 mm/s with at least the additional speeds of 15 mm and 60 mm/s selectable during operation. Note : - The writing unit may be replaced by a digital screen in modern EEG devices Ahmed Nazar mustafa university of duhok/college of medicine

9. Mechanism Of EEG The billions of nerve cells in The brain produce very small electrical signals that form patterns called brain waves. During an EEG , small electrodes and wires are attached to your head. The electrodes detect your brain waves and the EEG machine amplifies the signals and records them in a wave pattern on graph paper or a computer screen. Ahmed Nazar mustafa university of duhok/college of medicine

10. EEG Waveform EEG waveforms are generally classified according to their frequency, amplitude, and shape, as well as the sites on the scalp at which they are recorded. The most familiar classification uses EEG waveform frequency (e.g. alpha, beta, theta, and delta) [Figure below ] [Table below]. Ahmed Nazar mustafa university of duhok/college of medicine

11. EEG Waveform …. One way that scientists study EEG recordings is by looking at different waves in the EEG. These waves do not move across the body, but occur as changes in the signal at one place over time. They are studied using mathematical techniques for separating a signal into different frequencies (like the last figure) . The slowest waves are called delta, and they occur at 1 to 4 cycles per second. Delta occurs in sleep and during anesthesia. The next frequency is called theta, and it occurs at 4 to 8 cycles per second. Theta is seen when a person is trying to keep many different things, such as numbers or words, in memory. It is also seen when a person is drowsy. Ahmed Nazar mustafa university of duhok/college of medicine

12. EEG Waveform … . After theta comes alpha, a wave occurring at 8 to 12 cycles per second. Alpha is seen over the back of the head when a person has his or her eyes shut. It is also seen when a person is resting or meditating. Faster than alpha is beta, a wave that occurs at 12 to 30 cycles per second. It is seen when a person is getting ready to move or no longer resting. It is also seen when a person takes benzodiazepine drugs. Finally, gamma is the fastest wave seen in EEG, occurring at 30 to 100 cycles per second. It is seen when a person is thinking or paying attention to something Ahmed Nazar mustafa university of duhok/college of medicine

13. Normal Adult Brain Wave:- Ahmed Nazar mustafa university of duhok/college of medicine

14. Why is an EEG performed ( Advantages ) ?? In the Medical Field :- An EEG is used to detect problems in the electrical activity of the brain that may be associated with certain brain disorders. The measurements given by an EEG are used to confirm or rule out various conditions, including : ◾seizure disorders (such as epilepsy) ◾ head injury ◾ encephalitis (inflammation of the brain) ◾ brain tumor ◾ encephalopathy (disease that causes brain dysfunction) ◾ memory problems ◾ sleep disorders And also When someone is in a coma, an EEG may be performed to determine the level of brain activity. The test can also be used to monitor activity during brain surgery. Ahmed Nazar mustafa university of duhok/college of medicine

15. Risks of EEG (Disadvantages) The EEG has been used for many years and is considered a safe procedure. The test causes no discomfort. The electrodes record activity. They do not produce any sensation. In addition, there is no risk of getting an electric shock . BUT In rare instances, an EEG can cause seizures in a person with a seizure disorder. This is due to the flashing lights or the deep breathing that may be involved during the test. AND ALSO Other risks may be present, Certain factors or conditions may interfere with the reading of an EEG test. These include: caused Low blood sugar (hypoglycemia by fasting. Body or eye movement during the tests. Lights, especially bright or flashing ones Drinks containing caffeine, such as coffee and cola Oily hair or the presence of hair spray Ahmed Nazar mustafa university of duhok/college of medicine

16. Preparation for EEG:- The patient should ask his healthcare provider to tell them what they should do before the test. A- The patient will be asked to sign a consent form that gives him/her permission to do the procedure. B- The patient must wash his/her hair with shampoo, but conditioner must not be used the night before the test . C- The patient must Tell his/her healthcare provider of all medicines (prescription and over-the-counter) and herbal supplements that they are taking. D- The patient must Discontinue using medicines that may interfere with the test if the healthcare provider has directed him/her to do so. E- The patient must Avoid consuming any food or drinks containing caffeine for 8 to 12 hours before the test. F- If the patient is having a sleep EEG, he or she may be asked to stay awake the night before the exam. G- The patient must Avoid fasting the night before or the day of the procedure. Low blood sugar may influence the results . Ahmed Nazar mustafa university of duhok/college of medicine

17. Preparation for EEG :- Ahmed Nazar mustafa university of duhok/college of medicine

18. During the EEG procedure:- A standard noninvasive EEG takes about 1 hour. The patient will be positioned on a padded bed or table. To measure the electrical activity in various parts of the brain, a nurse or EEG technician will attach 16 to 20 electrodes to the scalp. The brain generates electrical impulses that these electrodes will pick up . To improve the conduction of these impulses to the electrodes, a gel will be applied to them. The electrodes only gather the impulses given off by the brain and do not transmit any stimulus to the brain. The technician may tell the patient to breathe slowly or quickly and may use visual stimuli such as flashing lights to see what happens in the brain when the patient sees these things. The brain's electrical activity is recorded continuously throughout the exam on special EEG paper. Ahmed Nazar mustafa university of duhok/college of medicine

19. After EEG procedure:- After the test is complete, the technician will remove the electrodes. The patient will be instructed when to resume any medications. The patient generally will be ready to go home immediately following the test. No recovery time is required. Because the patient may be at risk for a seizure (especially if their medication has been withheld prior to the EEG ). The patient should avoid activities that may harm them if a seizure occurs, until they have resumed their seizure medication for an adequate length of time. These precautions do not necessarily apply to the person who was not on any seizure medication prior to the EEG. The doctor or technician will tell the patient when and how they will learn the results of their EEG. Ahmed Nazar mustafa university of duhok /college of medicine

20. EEG results: When the EEG is finished, the results are interpreted by a neurologist , The EEG records the brain waves from various locations in the brain. Each area produces a different brain wave strip for the neurologist to interpret. When examining the recordings, the neurologist looks for certain patterns that represent problems in a particular area of the brain. For example, certain types of seizures have specific brain wave patterns that the trained neurologist recognizes. Likewise, a normal brain has a specific brain wave pattern that the trained neurologist recognizes The neurologist must look at all recorded tracings, decide what is normal and what is not, and determine what the abnormal tracings represent. The neurologist forwards the EEG results to the doctor who ordered the test, and the patient is then notified as arranged. Ahmed Nazar mustafa university of duhok/college of medicine

21. CONCLUSION :- Although the diagnoses od disease through EEG may seem simple to the reader, but it is not as simple as it seems, because in many diseases such as seizure, it does not cause a typical pattern on EEG, it just causes a change in the EEG. This means that sometime the EEG is described as ‘abnormal’ but does not specify the abnormality or disease . In general EEG is the best method to diagnose a disease and it is better than its alternatives for many reasons, and there are almost no low-cost alternatives to EEG. Ahmed Nazar mustafa university of duhok/college of medicine

22. Prepared BY :- 1- Jaber Mahmud Abdulrahman 2- Ahmed Nazar Mustafa 3-Omed Xthr Habib 4-Azad Khalid Sulayman 5-Alla Abdulrazaq Mustafa 6- Ahmed Thati Hassan 7- Ayman Thsin Ibrahim 8- Payan Younes Mohammed 9- Aza Njiar Najeeb 10- Bizhar Ahmed Mohammed Ahmed Nazar mustafa university of duhok/college of medicine

23. Thank You For Your Attention Ahmed Nazar mustafa university of duhok/college of medicine