Eeg from a to z

In the Name of God

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EEG(electroencephalography)

Seyedeh Shokoofeh Mousavi GazafroudiSeyedeh Shabnam Mousavi Gazafroudi

05/02/2023Isfahan university of m

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05/02/2023Isfahan university of medical sciences

3Outline

Introduction & history EEG component EEG procedure Basis of EEG Waves & activation Indication & artifact Strength Vs. limitation of the

test developments


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EEG Introduction

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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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History

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7History

Isfahan university of medical sciences


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EEG component


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EEG

Electrodes

Filters

Amplifiers

Recording unit


10ElectrodeCup shape or aciform for collecting waves Unipolar or bipolar connection (montage)

FilterReduce artifact

AmplifierModifying oscillation amplitude

Recording unit8-24 apart channel5-10 specific software


11EEG machine

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EEG procedure


13What’s happen during EEG test?

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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Basis of EEG


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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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EEG Electrode

18Electrodes

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, storage05/02/2023Isfahan university of medical sciences


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Types & placement

20Electrode 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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Brain waves


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Type of studies


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Artifact


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Indication


30EEG 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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Example

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Eye open

Eye close



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Advantage & Disadvantage


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Developments(MEG, ECOG & QEEG)

36Similar tests

ElectroCorticoGraphy MagnetoEncephaloGraphyQuantitative EEG



Thank you

Eeg from a to z

Health & Medicine

Transcript of Eeg from a to z