Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

IONM Training + CNIM Board Prep > SSEPs > Flashcards

SSEPs Flashcards

(71 cards)

Start Studying
1
Q

Name the muscle activated with stim of the MN at the wrist

A

Thenar muscle group : Abductor Pollicis Brevis (APB)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Name the muscle activated with stim of the UN at the wrist

A

Hypothenar group : Abductor Digiti Minimi (ADM)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Define Orthodromic

A

The direction a signal normally travels

e.g. SSEPs afferent (up), tcMEPs efferent (down)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Define Antidromic

A

The direction opposite to which a signal normally travels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What happens when Stimulus Intensity is reduced?

A

Amplitude decreases

Most pronounced in Erb’s Point and Pop Fossa (peripheral responses)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What happens when Patient’s body temperature drops?

A

Latency increases, amplitude stays the same

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What happens to an the Erb’s Point response during ischemia (positional, BP cuff, weighting of the head, taping of the shoulders)?

A

Both latency and amplitude decrease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the function of Erb’s Point/Pop Fossa according to the guidelines?

A

To verify adequate stimulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What type of montage is best for recording subcortical or far field SSEP responses?

A

Referential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What type of montage is best for recording SSEP cortical responses?

A

Bipolar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which peak is most susceptible to anesthesia effects?

A

N20

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What time does EP to N20 define?

A

the conduction time between the brachial plexus and the primary sensory cortex

(aka central conduction)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What time does the EP latency define?

A

Peripheral conduction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does EP to P14 define?

A

The conduction time between the brachial plexus and the lower brainstem

(central conduction)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does P14 to N20 define?

A

The conduction time between the lower brainstem and the cortex

(central conduction)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Define Lumbar Potential

A

Stationary/non-propagated potential reflecting mainly postsynaptic activity in the lumbar cord from internuncial neurons (relay neurons)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What metal is best for Epidural Spine electrodes?

A

Platinum iridium-guards against neurotoxicity

Alternate electrodes are stainless steel or platinum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the most common technical problem with epidural electrodes?

A

Shunting from fluid over the electrode

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What type of stimulation is best for SSEPs?

A

Constant current

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What does an increase in stimulus intensity do to the SSEP?

A

Does not change latency, increases amplitude to a maximum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is asynchronous stimulation?

A

Stimulation with delay

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Define false positive data

A

significant changes in data, but no deficits post-operatively

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Define false negative data

A

No changes in data, but patient has post-operative deficits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

During upper extremity SSEP recording, the Erb’s Point electrode records data from where?

A

Brachial Plexus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Hypothermia of the lower extremities will result in
prolonged peripheral conduction time
26
What's the most common injury during an ALIF?
left iliac artery injury
27
What are the dorsal column tracts for Lower Extremity SSEPs?
Fasciculus Gracilis, Nucleus Gracilis Think "G" for Ground (Which is LOW)
28
What are the dorsal column tracts for Upper Extremity SSEPs?
Fasciculus Cuneatus, Nucleus Cuneatus Think "C" for Clouds (which are UP)
29
What is the lumbar potential and which artery supplies the area?
Lower Extremity SSEP Obligate Waveform (not commonly recorded in OR) Stationary, post-synaptic potential generated by the Spinal Cord, Near Field Potential Supplied by the Artery of Adamkiewicz
30
What is N34 and which artery supplies the area?
Lower Extremity SSEP Obligate Waveform Subcortical Response, generated by the Brainstem/Thalamus, Far Field Potential Supplied by Basilar Artery
31
What is the P37 and which artery supplies the area?
Lower Extremity SSEP Obligate Waveform Cortical Response generated by the Somatosensory Cortex Supplied by Anterior Cerebral Artery (ACA)
32
What is the N9 and which artery supplies the area?
Upper Extremity SSEP Obligate Waveform Peripheral Response generated by Brachial Plexus, Near Field Response Supplied by Subclavian Artery
33
What is the N13 and which artery supplies the area?
Upper Extremity SSEP Obligate Waveform Stationary, post-synaptic potential generated by Upper Cervical Spinal Cord Recorded from dorsal neck, Near Field Potential Supplied by Posterior Spinal Arteries
34
What is the N18 and which artery supplies the area?
Upper Extremity SSEP Obligate Waveform Subcortical Response, Far Field response generated by Brainstem/Thalamus Supplied by Basilar Artery
35
What is the N20 and which artery supplies the area?
Upper Extremity SSEP Obligate Waveform Cortical response, Near Field Potential generated by the Somatosensory Cortex Supplied by Middle Cerebral Artery (MCA)
36
What does "subcortical" mean?
SSEP response generated by the brainstem/thalamus think "below cortical" N18 Upper Extremity SSEP N34 Lower Extremity SSEP
37
N20 response recorded from CPc-Fpz Is it a near field or far field potential?
Near field
38
**N34** Near field or far field?
**Far field** brainstem response
39
Dermatomal SSEPs follow what pathway?
Dorsal column / Medial Lemniscus pathway
40
Name the generator for the N18 waveform
Upper Brainstem/Thalamus
41
Stimulation of what nerve(s) provides the most effective somatosensory monitoring of upper limb positioning during prone spine surgery?
Ulnar & Median Nerve SSEP combined
42
What is the anatomical generator of the P20 response recorded directly over the cortex during phase reversal mapping?
somatosensory cortex
43
Most appropriate nerve to stimulate for recording robust UE SSEPs during cerebrovascular procedures?
Median nerve
44
Which nucleus is the termination of the first order of the SSEP pathway for the upper extremities?
Nucleus Cuneatus
45
The termination of the second order of the SSEP pathway is in the
Thalamus
46
Cortical ischemia caused by the Middle cerebral artery (MCA) would cause what SSEP data changes?
Decrease (attenuation) of a unilateral _cortical_ SSEP responses along with _stable_ subcortical waveforms (median nerve stimulation)
47
If the surgeons clamps the left Internal Carotid Artery (ICA), which waveform is most likely to attenuate if the patient does not have adequate collateral perfusion?
Right upper extremity (RUE) SSEP
48
Injury to the SSEP pathway causes what symptoms?
Numbness, Loss of Vibration Sense, Loss of Conscious Proprioception
49
Occlusion of which vessel is most likely to correlate with a decrease in left lower extremity cortical SSEPs?
Right Anterior Cerebral Artery (ACA)
50
Somatosensory evoked potentials would most likely be analyzed in the clinical diagnosis of which condition? * Myasthenia Gravis * Multiple Sclerosis * Alzheimer's Disease * Hydrocephalus
**Multiple Sclerosis** *Why? MS is a demyelinating disease. Demyelination causes a decrease (slowing) in the conduction velocity which would result in an INCREASE in the LATENCY of SSEP responses*
51
Generator for N9 Response
Peripheral Nerve
52
Is the P37 a positive or negative response?
Positive
53
Generator for N13
Spinal cord
54
SSEP recordings of P37 and N45 waveforms are likely the result of stimulation to what nerve?
Posterior Tibial Nerve (PTN)
55
SSEP recordings of N20 and P23 waveforms are likely the result of stimulation to what nerve?
Median or Ulnar Nerves
56
During a posterior thoracic fusion, the spinal cord is injured and causes swelling. What SSEP response will remain stable despite injury to the cord?
The pop fossa (peripheral) response will remain unchanged following a spinal cord injury
57
During a posterior thoracic fusion, the spinal cord is injured and causes swelling. What SSEP responses do you expect to observe changes from?
Decrease or loss of subcortical and cortical waveforms.
58
Alert criteria for SSEP
50% decrease in amplitude 10% increase in latency
59
65% nitrous oxide will cause the _greatest_ amplitude decrease to what SSEP response? * N20 * N13 * N9
**N20**
60
Ulnar nerve SSEPs can be used to detect ischemia (loss of perfusion) to what structures? (Name 3)
* Limb ischemia * Spinal Cord ischemia * Cortical ischemia
61
What would explain why cortical SSEP amplitudes are often smaller or less robust compared to subcortical SSEP amplitudes?
The thalamocortical projection adds an _additional synapse_ before the signal reaches the cortex, making the cortical signal more susceptible to anesthesia effects
62
Following **left** ulnar nerve stimulation, which **_active electrode_** will produce an upward deflection at approximately 20 milliseconds, when applied to the negative input of the amplifier?
63
When stimulating a peripheral nerve to elicit an afferent response, the anode should be placed ___ to the cathode
Anode should be placed **_distal_** to the cathode
64
Erb's point is valuable in monitoring. Give three reasons.
* verify adequate stimulus * helps in detection of limb ischemia * aid in detection of brachial plexus injury
65
You are obtaining baseline data from a patient with diabetic peripheral neuropathy. Your PTN SSEPs are unreliable. What efforts should you take to try obtaining reliable data?
* Increase pulse width * Decrease the rep rate below 3Hz * Stimulate at the pop fossa location
66
The Surgeon requests relaxant be given during your procedure. What effect will paralytics have on your SSEPs?
May improve artifact, otherwise no effect
67
During a posterior thoracolumbar fusion, you observe a total loss of bilateral lower extremity SSEP waveforms. tcMEP CMAPs are robust and show no changes. Could a spinal cord injury be present?
Yes, with the posterior approach these SSEP changes may represent **spinal cord injury**, despite the unchanged tcMEP data. *Think about the approach of surgery and what structures are at risk. In this case, a _posterior_ approach puts the _dorsal column_ at most risk. Dorsal column is where the SSEP pathway is located. It is possible to have a partial spinal cord injury, leaving the anterior portion of the cord intact and fully functional.*
68
The first synapse in the dorsal column/medial lemniscus pathway takes place where?
Medulla
69
A sensory response recorded at 9ms after ulnar nerve stimulation represents
A peripheral nerve action potential
70
Increasing number of averages (trials) can help reduce what in the SSEP?
Electrical artifact/noise
71
1. In which type of evoked potential is the scalp position of recording electrodes _most_ critical? * Electrocochleogram * BAEPs * Cognitive evoked potentials * Lower extremity SSEPs
Lower extremity SSEPs *Think of the homunculus and where lower extremities are located (midline). They have less cortical representation - thus its very important electrode placement is placed correctly.*

IONM Training + CNIM Board Prep (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions