EEG INTRODUCTION, EEG HISTORY, EEG PROCEDURE, BRAIN WAVES, EEG ARTIFACT, EEG INDICATION, LIMITATION AND STRENGTH

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3. Outline
 Introduction & history
 EEG component
 EEG procedure
 Basis of EEG
 Waves & activation
 Indication & artifact
 Strength Vs. limitation of the test
 developments
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4. EEG Introduction
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5.  EEGs are used to test the health & function of brain.
 Spontaneous electrical activity of the cortex is recorded.
 Brainwave can be collected by electrodes & they are monitored on a machine.
Introduction
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6. History
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7. History
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8. EEG component
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9. EEG
Electrodes
Filters
Amplifiers
Recording
unit
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10. Electrode
Cup shape or aciform
for collecting waves
Unipolar or bipolar connection (montage)
Filter
Reduce artifact
Amplifier
Modifying oscillation amplitude
Recording unit
8-24 apart channel
5-10 specific software
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11. EEG machine
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12. EEG procedure
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13. What’s happen during EEG test?
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14. Preparation & Procedure
 Washing the hair (if patient so desire)
 Avoid using hair spray or oily scalp
products 24hr before the test
 Avoid caffeinated drinks
 Eating a light meal within 4hr of test
 Sometimes may ask the patient to stay
awake for all or part of night before test
 measuring & marking places of electrode
 Using of a cleanser then attaching the disk
with gel or cream
 Technician may ask patient to open & close
eyes, or to do a breathing exercise
 It takes about 1hr
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15. Basis of EEG
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16.  Cortical pyramidal neurons produce most of the
EEG signals
 EEG reflects the summation of the synchronous
activity of many neurons with similar spatial
orientation
 Frequency spectrum of these signals has helpful
diagnostic information
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17. EEG Electrode
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18. Electrodes
 They receive brain electric waves, these waves are weak and should be amplified
 21 or 64 electrodes are used depend on electrodes system
 Electrodes appellation:
Even number: right. Odd : left.
C=central; F=frontal; P=parietal; T=temporal; O=occipital
 Electrodes allow undistorted recordings of a frequency range of 0.5 –70Hz. The electrodes is made up of
silver/silver chloride (Ag/AgCl) or gold cup
 Data acquisition involves : amplification, filtering, digitizing, storage
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19. Types & placement
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20. Electrode placement systems
Names reflect the fact that electrodes are placed at interval that are 10% or 20% of the distance between landmarks.
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21. Brain waves
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23. Type of studies
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27. Artifact
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29. Indication
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30. EEG Is used for …
 Study of epilepsy and similar disorders
 Unjustified attack of unconsciousness
 Headache & vertigo attack
 Abnormal body movement
 Psychological disorder (depression, dementia,…)
 Some of brain lesion
 Daze attacks & unresponsiveness in children
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31. Example
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32. Eye open
Eye close
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33. Advantage & Disadvantage
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35. Developments
(MEG, ECOG & QEEG)
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36. Similar tests
ElectroCorticoGraphy MagnetoEncephaloGraphyQuantitative EEG
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