EEG Basics

Question 1

What does an EEG record ?

Answer 1

Post-synaptic potentials (majority), action potentials and chronic neuronal depolarization but most likely the voltage of the EC matrix.

Question 2

Two types of Post-synaptic potentials

Answer 2

Inhibitory and Excitatory

Question 3

What is the PDR

Answer 3

posterior dominant rhythm is the basic rhythmic frequency of the normal awake adult brain.

Question 4

What leads to rhythmic cortical activation

Answer 4

thalamic pacemaker cells.

Question 5

Potential fields are ___ in shape and have a ____ effect.

Answer 5

oval/ripple.

Question 6

Bipolar Recording: If input 1 is negative with respect to input 2 the deflection is

Answer 6

upward

Question 7

If input 2 is negative with respect to input 1 the deflection is ?

Answer 7

downward

Question 8

Bipolar recording

Answer 8

two successive electrodes are compared

Question 9

Three types of montages

Answer 9

double bannana, transverse, circumferential

Question 10

Multifocal definition

Answer 10

discharge in more than 3 non-contiguous leads and two different hemispheres

Question 11

Impedence should not exceed

Answer 11

5 kohms

Question 12

Standard sensitivity and brain death criteria

Answer 12

7 microvolts should be turned down to 2 for brain death criteria.

Question 13

Purpose of notch filter

Answer 13

set at 60hz to block out electronic devices.

Question 14

Gamma, beta, alpha, theta and delta frequencies

Answer 14

> 30, 13-30, 8.5-13, 4-8.5, and 0-4

Question 15

Acceptable asymmetry of PDR

Answer 15

2:1

Question 16

Stage 1 sleep: 2 features

Answer 16

vertex waves and POSTs

Question 17

Stage 2 sleep: 2 features

Answer 17

sleep spindles and k-complexes

Question 18

Def of a slow PDR

Answer 18

<8.5 hz

Question 19

Def sleep spindles

Answer 19

sinusoidal, synchronous and at 12-14 hz

Question 20

Def of k-complexes

Answer 20

bi/triphasic waves >500ms

Question 21

4 normal variants

Answer 21

alpha, mu, lambda, 14/6

Question 22

Define alpha variants

Answer 22

half to double the PDR is okay

Question 23

define mu rhythm

Answer 23

se over c3/c4 (motor strip, attenuates with movement of the opposite limb

Question 24

define lambdas

Answer 24

electropositive transients in occipital regions

Question 25

define 14/6

Answer 25

14 hz and 6hz spikes singular and in clusters usually in posterior quadrants.

Question 26

three levels of slowing

Answer 26

0-4 severe
4-7 hz moderate
7-8 hz - mild

Question 27

Duration of spike

Answer 27

20-70ms

Question 28

Duration of sharp

Answer 28

70-200ms

Question 29

GPEDS are seen in what clinical states

Answer 29

diffuse injury (toxic-metabolic,hypoxic ischemic)

Question 30

PLDs are seen in what clinical states

Answer 30

focal lateralized lesions (brain abscess etc)

Question 31

Define evolution

Answer 31

2 unequivocal, sequential changes in frequency morphology and location.

Question 32

Principle of localization in bipolar montage ?

Answer 32

Phase reversal

Question 33

Principle of localization in referential montage ?

Answer 33

Amplitude