Eeg - Montages

Front 1

Derivation

Back 1

The paring of eletrodes in a differential amplifier

Front 2

Channel

Back 2

Displays the difference in electrical potential recorded between 2 electrodes of the derivation

Front 3

Montage

Back 3

Logically sequencing dervations by planes to systematically view the electrical energy of the brain

Front 4

What is the 10-10 system?

Back 4

Used in epilepsy and others- when electrodes are placed inbewteen the 10-20 electrodes for a more

Front 5

What are the two types of montages?

Back 5

Bipolar and referential

Front 6

What is a bipolar montage?

Back 6

Created when input 2 electrode is the input 1 electrode of the next channel

Front 7

Longitudinal Bipolar

Back 7

Anterior to posterior (front to back) - double banana

Front 8

Transverse Bipolar

Back 8

(left to right across the head)

Front 9

Circumferential Bipolar

Back 9

Around the head passing through 10% marks (hatband/halo)

Front 10

What channels make up the left parasagittal?

Back 10

Fp1 - F3; F3 - C3; C3 - P3- P3 - 01

Front 11

What channels make up the right parasagital?

Back 11

Fp2 - f4; F4 - C4; C4 - P4; P4 - O2

Front 12

What channels make up the left temporal?

Back 12

Fp1 - F7; F7 - T3; T3 - T5; T5 - O1

Front 13

What channels make up the right temporal?

Back 13

Fp2 - F8; F8 - T4; T4 - T6; T6 - O2

Front 14

What channels make up the sagittal?

Back 14

Fz - Cz; Cz - Pz

Front 15

What is an advantage of a longitudinal montage?

Back 15

Clear tracing due to noise cancelation- each group starts with an eye movement artifact and ends with alpha- phase reversals easy to identify- easy to view symmetry between hempispheres

Front 16

What is a Common Mode?

Back 16

The area between two electrodes that both electrodes pick up and is therefore canceled out

Front 17

What are the disadvantages of a longitudinal Montage?

Back 17

not a true representation of volatage due to cancelation - difficult to determine if activity that stands out is dominant in the parasagittal or temporal areas- end of chains are only partially localized

Front 18

Advantages of transvers bipolar montage

Back 18

clear tracing due to noise cancellation- left to right across midline helps distinguish if activity that stands out is dominant in the parasagittal or temporal areas

Front 19

Disadvantage of a transverse bipolar montage

Back 19

Symmetry between hemispheres not as well detected as LB

Front 20

Advantages of a circumferential Bipolar Montage?

Back 20

Further localize at the end of the chain - effects Fp1- Fp2- O1- O2

Front 21

Disadvantage of a circumfrential bipolar montage

Back 21

Can be confusing when looking at frontopolar and occipital areas

Front 22

Advantages of a referntial Montage?

Back 22

True representation of voltage (quiet reference)

Front 23

Disadvantages of referntial Montage?

Back 23

Contaminated reference- Reference electrode not really neutral.

Front 24

What are the arrangements of referential montage?

Back 24

Left/Right Military style- Vertex Style (referenced to Cz)

Front 25

What is an average reference montage?

Back 25

Mathematical calculation - adds the voltages of each electrode and divides the total number of electrodes. Usually omits electrodes with higher voltages and electrodes effected by a focus

Front 26

advantages of an average reference montage

Back 26

true representation of voltage (quiet reference)- localilize focal activity- if the same noise is present in all electrodes then the refernce elecrode will cancel all that out

Front 27

disadvantages of an average reference montage

Back 27

reference is not really neutral- hard to determine what electrodes to use in the reference- contamination of reference

Front 28

Laplacian reference montage

Back 28

The reference is a mathmatical average of four surrounding electrodes (example C3 - referenced to average (F3 + P3 + Cz + Tz)/4

Front 29

advantages of laplacian reference

Back 29

true representation of voltage- helps localize focal activity

Front 30

disadvantages of laplacian reference

Back 30

reference electrode not really neutral- hard to determine electrodes to include when 1 electrode is on the edge of the array- contamination of reference- different reference for each electrode

Front 31

Things to help us visually see an EEG

Back 31

Leave a gap between planes- change color of planes

Front 32

What is the system reference?

Back 32

incoming signal is recorded using a common reference electrode- the computer then cancels out what is common in all of the electrodes to get the true voltage of each input and cancel out the reference montage