Electrophysiology

Question 1

ECG

Answer 1

electro-cardiogram; heart; spontaneous

Question 2

ERG

Answer 2

electroretinogram; retina, light induced

Question 3

EOG

Answer 3

electro-oculogram; eye; standing potential

Question 4

EEG

Answer 4

Electro-encephalogram; brain; spontaneous

Question 5

VEP

Answer 5

Visual evoked potential;

Question 6

AEP

Answer 6

Auditory evoked potential;

Question 7

SEP

Answer 7

Somatosensory evoked potential;

Question 8

ERP

Answer 8

Event related potential

Question 9

Full-field flash ERG

Answer 9

recording of the electrical field generated by the retina in response to abrupt changes in light; electrical field changes when light alters the dark current and induces changes in neural activity within the IPL and OPL

Question 10

A-wave

Answer 10

flash interrupts the dark current (generated by photoreceptors)
-initial dip in graph-

Question 11

B-wave

Answer 11

neural activity within the IPL and OPL (may primarily reflect bipolar cell activity)
-steep climb in graph-

Question 12

Oscillatory potentials

Answer 12

lateral interactions between cells

- steps in steep climb/b-wave-

Question 13

Extinguished

Answer 13

No ERG to any stimulus

Question 14

Diminished

Answer 14

dama

Question 15

pan-retinal photocoagulation

Answer 15

found in diabetic retinophaty

Question 16

normal dark-adapted, absent light-adapted ERG

Answer 16

no cone function (monochromacy)

Question 17

normal A-wave, abnormal B-wave

Answer 17

dysfunctional bipolar cells “negative ERG”

ex. congenital stationary night blindness, X-linked retinoschesis

Question 18

progressive abnormalities

Answer 18

ERG loss may precede functional loss - gradual reduction in ERG response.
ex. retinitis pigmentosa, retinal dystrophies, melanoma associated retinopathy, carcinoma associated retinopathy

Question 19

outer retinal function

Answer 19

a-wave

Question 20

middle retinal function

Answer 20

b-wave

Question 21

PERG

Answer 21

pattern electroretinogram

the electric field generated by the retina to a pattern - no average luminance

Question 22

glaucoma test

Answer 22

PERG

Question 23

PERG testing which cells

Answer 23

amacrine and ganglion

Question 24

standard PERG clinical steps

Answer 24

checkerboard, no dilation, let patient blink, average of 150+ readings

Question 25

mfERG

Answer 25

multifocal ERG: identifies and/or monitors regional dysfunction in the retina,

Question 26

m-sequence

Answer 26

pseudorandom, checking different portions of retina

Question 27

electro-oculogram physiological basis

Answer 27

tight junctions | RPE and outer photoreceptor

Question 28

standing potential of eye (EOG)

Answer 28

measured by eye movement

Question 29

standard EOG

Answer 29

alternate fixation +/- 15 degrees, record 10 saccades each minute

Question 30

arden ratio

Answer 30

light peak/dark trough | normal range 1.4 - 3.0

Question 31

is EOG sine wave or square wave

Answer 31

square wave, ignoring titers (inaccurate fixation/overshoots and blinks)

Question 32

EOG more shallow/but faster

Answer 32

Best's disease

Question 33

VEP

Answer 33

visual evoked potential - part of the electroencephalogram from the visual cortex that is associated with vision

Question 34

physiological basis of VEP

Answer 34

visual responses can be recorded because they are time-locked to a visual stimulus - ion

Question 35

VEP represents....

Answer 35

macula/acuity

Question 36

ERG represents....

Answer 36

widespread retinal loss

Question 37

percent of retinal area is the macula

Answer 37

5 percent

Question 38

percent of visual cortex that processes macular function

Answer 38

80 percent

Question 39

pattern VEP

Answer 39

more sensitive, less variable, require fixation and resolution

Question 40

VEP maturation

Answer 40

transmission time (stimulus to processing stimulus) reduces between birth and 4 months

Question 41

optimal VEP pattern at birth

Answer 41

bright flash or large pattern

Question 42

optimal VEP pattern for adults

Answer 42

small checker

Question 43

Delays in VEP amplitudes

Answer 43

indicate dysfunction of macular pathway

Question 44

Smaller checks

Answer 44

longer peak latenciy

Question 45

lower contrast

Answer 45

longer peak latency

Question 46

standard VEP set-up

Answer 46

active electrode on occipital scalp and reference electrode on frontal scalp

Question 47

clinical application of VEP

Answer 47

evaluation of macular pathways, assessments of visual pathway routing,

Question 48

albinism

Answer 48

visual route defects due to melanin defect

Question 49

can binocular detect monocular defects in VEP?

Answer 49

no - can only detect after monocular