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CU Child Neuro Epilepsy > EEG Basics > Flashcards

Flashcards in EEG Basics Deck (33)
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1
Q

What does an EEG record ?

A

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

2
Q

Two types of Post-synaptic potentials

A

Inhibitory and Excitatory

3
Q

What is the PDR

A

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

4
Q

What leads to rhythmic cortical activation

A

thalamic pacemaker cells.

5
Q

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

A

oval/ripple.

6
Q

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

A

upward

7
Q

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

A

downward

8
Q

Bipolar recording

A

two successive electrodes are compared

9
Q

Three types of montages

A

double bannana, transverse, circumferential

10
Q

Multifocal definition

A

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

11
Q

Impedence should not exceed

A

5 kohms

12
Q

Standard sensitivity and brain death criteria

A

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

13
Q

Purpose of notch filter

A

set at 60hz to block out electronic devices.

14
Q

Gamma, beta, alpha, theta and delta frequencies

A

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

15
Q

Acceptable asymmetry of PDR

A

2:1

16
Q

Stage 1 sleep: 2 features

A

vertex waves and POSTs

17
Q

Stage 2 sleep: 2 features

A

sleep spindles and k-complexes

18
Q

Def of a slow PDR

A

<8.5 hz

19
Q

Def sleep spindles

A

sinusoidal, synchronous and at 12-14 hz

20
Q

Def of k-complexes

A

bi/triphasic waves >500ms

21
Q

4 normal variants

A

alpha, mu, lambda, 14/6

22
Q

Define alpha variants

A

half to double the PDR is okay

23
Q

define mu rhythm

A

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

24
Q

define lambdas

A

electropositive transients in occipital regions

25
Q

define 14/6

A

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

26
Q

three levels of slowing

A

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

27
Q

Duration of spike

A

20-70ms

28
Q

Duration of sharp

A

70-200ms

29
Q

GPEDS are seen in what clinical states

A

diffuse injury (toxic-metabolic,hypoxic ischemic)

30
Q

PLDs are seen in what clinical states

A

focal lateralized lesions (brain abscess etc)

31
Q

Define evolution

A

2 unequivocal, sequential changes in frequency morphology and location.

32
Q

Principle of localization in bipolar montage ?

A

Phase reversal

33
Q

Principle of localization in referential montage ?

A

Amplitude