Ch 13 - Neurophysiology

Question 1

what is an EEG

Answer 1

summation of excitatory and inhibitory postsynaptic potentials of pyramid neurons.

Question 2

How many cm2 of cortex is needed to produce an EEG field

Answer 2

6cm2

EEG = PPP + 6

Question 3

How many frequencies on a delta wave? Theta? Alpha? Beta?

Answer 3

D = 0-4

T = 4-8

A = 8-13

B = >13

Dig That Awesome Beat

Question 4

Upward vs downward EEG deflections:

Answer 4

Each EEG channel is a comparison of two inputs

+ > - = downward deflection

• > + = upward

Question 5

Bipolar montage:

Answer 5

Input 1 and 2 are adjacent, and input 2 is input 1 in the next channel

Fp1 - F3

F3-C3

C3-P3

Question 6

Referential montage:

Answer 6

Input 2 is presumed inactive

Fp1 - Cz

F3 - Cz

C3 - Cz

All channels are in reference to Cz

Question 7

Hyperventilation during EEG is contraindicated in:

Answer 7

Stroke

Sickle Cell

Cystic Fibrosis

Congenital Heart Dz

Asthma

Moyamoya

Hyperventilation is a SSCCAM

Question 8

Normal finding on EEG during hyperventilation?

Answer 8

Generalized background slowing

Question 9

Prolonged slowing can be seen on hyperventilation on EEG if?

Answer 9

Patient is hypoxic or hypoglycemic

Question 10

Photic stimulation is performed after what age?

Answer 10

>6 months old

Question 11

photomyoclonic response to photic stim?

Answer 11

when muscle contractions, such as contraction of the eyelids occur during photic stim

Question 12

photoparoxysmal response to photic stim?

Answer 12

when photic stim results in epileptiform discharge. This is seen in patients with JME

Question 13

photoconvulsive response to photic stim?

Answer 13

When stim results in a seizure. (usually seen in primary generalized epilepsy)

Question 14

Background rhythm on EEG with age?

Answer 14

At 3 mo, the posterior background rhythm should be 3Hz, and at 5 mo it should be 5Hz.

By age 3 yo, the awake background rhythm should reach alpha frequency.

Question 15

Kappa waves?

Answer 15

low amplitude waves in the temporal regions of the alpha or theta frequency (4-13). They occur during cognitive tasks or thinking.

Phi Beta KAPPA members have complex thoughts.

Question 16

Lambda waves?

Answer 16

positive sharp transients in the occipital area seen during visual scanning.

You can have lambda waves if you look around at a bunch of lambs.

Question 17

Mu rhythm?

Answer 17

7-11 Hz activity seen best over the centroparietal regions. Attenuated by movement of the contralateral body.

Mu is attenuated by MUvement.

Question 18

Wicket spikes/waves?

Answer 18

seen during drowsiness or light sleep in adults

6-11 Hz activity in the temporal region

Most adults are wicked drowsy at 6:11am

Question 19

Posterior slow waves of youth?

Answer 19

delta activity with overriding alpha frequencies

Question 20

14 and 6 positive bursts

Answer 20

seen during drowsiness and light sleep commonly in adolescents

bursts of arciform activity at 14 or 6 hz over posterior temporal head regions lasting for less than 3 seconds

Question 21

Siz hertz spike and wave bursts/ phantom spike and wave

Answer 21

seen in teens and adults during wakefulness and drowsiness. Disappear in sleep

Bursts of diffuse 6 Hz very small spike and higher amplitude wave discharges lasting a couple seconds.

Question 22

small sharp spikes of sleep

Answer 22

seen in drowsiness and light sleep in adults

brief, low voltage spikes over the temporal regions

Question 23

Rhythmic temporal theta bursts of drowsiness/ psychomotor variant pattern?

Answer 23

seen in drowsiness in young adults

5-7 Hz sharply contoured theta activity that occurs in bursts in the temporal region

Question 24

eyeblink artifact?

Answer 24

cornea is positive and retina is negative

When the eye closes, a positive deflection is seen in Fp1 and Fp2

When the eye opens, a negative deflection is seen

I’m positive that I’d like to close my eyes and take a nap

NEO has nice PECs

(remember positive is downward and negative is upward on EEG)

Question 25

Lateral eye movement artifact?

Answer 25

usually produce an artifact on F7 and F8

Look Left = positive on F7 and neg F8

Look right = negative F7 and pos F8

You look in the direction of positivity

Question 26

2 Types of alpha coma?

Answer 26

1. posterior dominant alpha activity that is poorly reactive. (common in brainstem lesions)
2. diffuse or frontal alpha activity that is poorly reactive.

Seen in anoxia

Alpha comas are seen in Anoxia and Arrest

Question 27

Bancaud’s phenomenon?

Answer 27

When the alpha activity over one hemi does not attenuated with eye opening. The nonreactive hemi is abnormal

Question 28

Beta coma?

Answer 28

high amplitude generalized beta activity

Commonly seen in encephalopathy 2/2 medication, and some acute brainstem lesions.

Beta has a BETter prognosis than alpha coma.

Beta coma may be when youre Buzzed

Alpha is awful, Beta is better

Question 29

breach rhythm?

Answer 29

due to a skull defect, the EEG activity may be higher in amplitude and spiky looking.

Question 30

burst suppression?

Answer 30

can be induced with pentobarbital or midazolam gtt

carries a very poor prognosis in the setting of hypoxic injury

Question 31

delta activity on EEG?

Answer 31

if continuous and polymorphic, may be due to a structural lesion

Question 32

Types of epileptiform discharges: Spike vs sharp waves?

Answer 32

spike = <70 ms in duration

sharp wave is 70-200 ms in duration