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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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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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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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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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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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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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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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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