Electrodiagnostic Studies Flashcards

1
Q

What 3 abnormal spontaneous activities seen on EMG arise from motor unit pathology

A
  1. Fasciculations
  2. Myokymic discharges
  3. Neuromyotonic discharge
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2
Q

What happens to SNAP in ALS

A

Normal

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3
Q

Amplitude of fibs and PSWs

A
Fibs = ~300 microvolts
PSWs = ~1000 microvolts
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4
Q

What is the initial deflection of myotonic discharge

A

Varies - can be positive deflection or biphasic or triphasic

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5
Q

What 2 muscles can you use for H-reflex

A

FCR and gastroc-soleus

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6
Q

what type of neuropathy is seen in diabetic neuropathy

A

axonal and demyelinating sensory motor neuropathy

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7
Q

Normal amplitude of a MUAP

A

1 mV

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8
Q

what is the correlation between firing frequency and recruitment pattern

A

increased firing frequency = decreased recruitment

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9
Q

Are large amplitude long duration MUAPs seen in myopathic or neuropathic processes

A

Neuropathic

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10
Q

Normal duration of a MUAP

A

5-15 ms

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11
Q

Are short duration small amplitude MUAPs seen in myopathic or neuropathic processes

A

Myopathic

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12
Q

in the newborn, nerve CV are what percentage of adult values

A

50%. 1 yo = 75% of adult values

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13
Q

What denervation potential sounds like dive bomber

A

Myotonic discharge

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14
Q

what type of neuropathy is seen in alcohol neuropathy

A

axonal sensory motor neuropathy

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15
Q

SSEPs only evaluates nerve fibers that sense _________ and __________

A

Vibration and proprioception

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16
Q

In a neuropathic process, what happens to recruitment pattern

A

Reduced recruitment

17
Q

What 4 abnormal spontaneous activities seen on EMG arise from muscle or nerve pathology

A
  1. Fibs
  2. PSWs
  3. Myotonic discharge
  4. Complex repetitive discharge
18
Q

What happens to MUAP amplitude, duration, and recruitment in myopathy?

A

Small amplitude, short duration, early recruitment

19
Q

What nerves are commonly used for testing in somatosensory evoked potentials

A

Median nerve for upper limb and tibial nerve for lower limb

20
Q

What denervation potential sounds like motor boat

A

CRDs

21
Q

What do somatosensory evoked potentials test?

A

Ascending sensory pathways to the somatosensory cortex

22
Q

In normal recruitment, what is the frequency of firing rate

A

Every 5 Hz another motor unit fires

23
Q

Which denervating potential sounds like marching soldiers

A

Myokymic discharge

24
Q

Miniature end plate potentials is also known as

A

Endplate noise

25
Q

side to side latency of H-reflex is significant if it is greater than what?

A

1.5 ms

26
Q

Are SSEPs done with submaximal or supramaximal stimulation?

A

Submaximal

27
Q

normal gain for sensory nerve study

A

20 microvolts/division

28
Q

What happens to conduction velocity if measured distance is falsely low

A

Conduction velocity will be falsely decreased. (Measured distance is 10cm, when it is actually 15cm will give you a slow conduction velocity when it is actually faster)

29
Q

Amplitude of miniature endplate potentials

A

10 to 50 microvolts

30
Q

Which denervating potential resembles a MUAP

A

Fasciculations

31
Q

What causes miniature end plate potentials

A

Release of individual quanta of ACh

32
Q

what happens to latency, CV and amplitude in a cold limb

A

latency increases
CV decreases
amplitude increases

33
Q

what type of neuropathy is seen in paraneoplastic syndrome

A

axonal sensory neuropathy

34
Q

What 3 main problems do SSEPs monitor for

A
  1. Peripheral nerve injuries
  2. Central nervous system lesions
  3. Intraoperative spinal surgery monitoring