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Flashcards in neurophysiology Deck (16):
1

what neurological disorders are nerve conduction studies useful in?

MND, radiculopathy, brachial neuritis, peripheral neuropathy, entrapment neuropathy, myasthenia gravis, Lambert Eaton Syndrome.

2

what is the latency ?

time between stimulus and potential

3

what are the normal conductance speeeds for an adult?

arm> 48ms leg >38ms

4

what happens to the action potential in demyelinating pathology?

it is delayed

5

what happens to the action potential in degeneration?

reduction in amplitude because there are fewer axonc contributing to the impluse.

6

what is a normal sensory amplitude?

> or = to 5 micro volts

7

what is an F wave?

conduction the opposite way up the nerve resulting in a second delayed wave

8

what is decrement?

when the nerve is repeatedly stimulated, the amplitude of the action potential diminishes with each impulse.

9

in what conditions would you find decrement?

lambert eaton, and myasthenia gravis

10

in which condition would you see increment and decrement?

lambert eaton myasthenic syndrome

11

what is increment?

initial excessive amplitude, followed by decrement.

12

what evoked potential tests can be done?

somatosensory EPs upper and lower limbs

VEPs/ERGs ( electroretinograms)

Auditory

MEP

13

what can SSEPs be used for?

test when suspected demyelination and myelopathy

IE ms
spinal cord lesions

14

what can VEP readings tell us

normal VEP: visual pathway intact

absent VEP: atrophy

unilateral latency: slowing of conduction ie demyelination

reduced amplitude: ischaemic disease of the eye and optic nerve

15

BAEPs can be used to

screen hearing in infants

evaluation of possible acoustic neuroma

evaluate peripheral and central auditory pathways in sedated and anethatised patients

16

what uses does Motor Evoked potential have?

diagnostic, assess connections between primary motor cotrex and various muscles

functional disorder