CNIM ABRET 2023 QUESTIONS AND ANSWERS
WITH COMPLETE SOLUTION
in which of the following evoked potentials is the scalp position of recording electrodes
most critical?
Lower extremitity SSEP
if an evoked potential has a voltage of 10 uV and the associated noise has a voltage of
50uV, waht is the signal to noise ration after 100 averages responses?
2:1
To display median nerve SSEP response as an upward deflection, which of the
following must be known?
waveform polarity and polarity convention of the amplifier inputs
If an amplifier is rated as having 120dB common mode rejection ratio, which of the
following ratios of in-phase to out-of-phase signals would be expected?
1,000,000:1
which cranial nerves innervate the extraocular muscles?
abducens
which is a SSEP far-field subcortical potential
N34 (UE far-field subcortical)
what is the segmental motor innervation of the pernoeus longus?
L4, L5, S1
what opposes any change in current?
Inductance
the dorsal column pathways synapse at which loci on their way to the sensory cortex?
nucleus cuneatus and thalamus
With referential recording, maximal amplitude cortical evoked potentials following
stimulation of the left posterior tibial nerve usually would be found between
C3 and Cz
For preoperative posterior tibial SSEPs, which of the following would be the best
ipsilateral location for the ground electrode?
Calf
To record the afferent volley after posterior tibial nerve stimulation, an electrode should
be placed on the:
T5 spine
Which of the following would result in the best resolution in the analog-to-digital
converter process?
The maximal peak-to-peak signal amplitude should match the converter range
An increase in stimulation intensity causes a linear increase of which of the following
SSEP components?
P31
Epidural electrodes are made of platinum because:
Other metals may become toxic when currents are applied
During a median nerve preoperative study, a patient has discomfort at the wrist.
Stimulation electrodes are 10mm gold disk, stimulus intensity is 20mA, and stimulus
, duration is 100uSec. Which of the following would most likely reduce the patient's
discomfort while maintaining adequate stimulation?
Decrease number of repetitions
Which of the following improves the signal-to-noise ratio by the square root of the
number of responses added?
signal averaging
In BAEPs, wave I can most easily be differentiated from cochlear microphonics based
upon:
Click polarity
What is the interstimulus interval of a 50Hz click stimulus?
20.00 msec
SSEPs recording from the scalp after electrical stimulation of the peripheral nerve are
conducted through the:
Dorsal column on the side of the stimulation
Monitoring the posterior tibial nerve SSEPs is most appropriate in cerebrovascular
procedures involving which of the following arteries?
Anterior cerebral
Identification of wave V of the BAEP may require:
Decreasing stimulus intensity
In spinal surgery, the primary purpose of the popliteal fossa recording electrode is to:
Verify adequacy of stimulus
While performing a posterior tibial SSEP, hypothermia of the lower extremities is most
likely to cause:
Slowed peripheral conduction velocities
Which of the following peaks in tibial nerve SSEPs is most analogous to P14 of median
nerve SSEPs?
P31
During posterior fossa surgery, when BAEPs are used for monitoring brainstem
function, it is most important to:
Stimulate and record from the contralateral side
Which of the following cranial nerves is most appropriate to monitor during the resection
of a 4cm vestibular schwannoma?
Facial
During a carotid endarterectomy, what SSEP modality is recommended for monitoring
cerebral function?
Median
If the EEG is preserved during carotid endarterectomy surgery, it indicates:
Adequate cortical perfusion and oxygenation
Alternating current is used when checking electrode impedance to:
Avoid electrode polarization
Which of the following is most likely to cause 60hz contamination of EP waveforms in
the operating room?
Fluorescent lights
A postincision baseline recording is used to
Establish a standard for the patient
WITH COMPLETE SOLUTION
in which of the following evoked potentials is the scalp position of recording electrodes
most critical?
Lower extremitity SSEP
if an evoked potential has a voltage of 10 uV and the associated noise has a voltage of
50uV, waht is the signal to noise ration after 100 averages responses?
2:1
To display median nerve SSEP response as an upward deflection, which of the
following must be known?
waveform polarity and polarity convention of the amplifier inputs
If an amplifier is rated as having 120dB common mode rejection ratio, which of the
following ratios of in-phase to out-of-phase signals would be expected?
1,000,000:1
which cranial nerves innervate the extraocular muscles?
abducens
which is a SSEP far-field subcortical potential
N34 (UE far-field subcortical)
what is the segmental motor innervation of the pernoeus longus?
L4, L5, S1
what opposes any change in current?
Inductance
the dorsal column pathways synapse at which loci on their way to the sensory cortex?
nucleus cuneatus and thalamus
With referential recording, maximal amplitude cortical evoked potentials following
stimulation of the left posterior tibial nerve usually would be found between
C3 and Cz
For preoperative posterior tibial SSEPs, which of the following would be the best
ipsilateral location for the ground electrode?
Calf
To record the afferent volley after posterior tibial nerve stimulation, an electrode should
be placed on the:
T5 spine
Which of the following would result in the best resolution in the analog-to-digital
converter process?
The maximal peak-to-peak signal amplitude should match the converter range
An increase in stimulation intensity causes a linear increase of which of the following
SSEP components?
P31
Epidural electrodes are made of platinum because:
Other metals may become toxic when currents are applied
During a median nerve preoperative study, a patient has discomfort at the wrist.
Stimulation electrodes are 10mm gold disk, stimulus intensity is 20mA, and stimulus
, duration is 100uSec. Which of the following would most likely reduce the patient's
discomfort while maintaining adequate stimulation?
Decrease number of repetitions
Which of the following improves the signal-to-noise ratio by the square root of the
number of responses added?
signal averaging
In BAEPs, wave I can most easily be differentiated from cochlear microphonics based
upon:
Click polarity
What is the interstimulus interval of a 50Hz click stimulus?
20.00 msec
SSEPs recording from the scalp after electrical stimulation of the peripheral nerve are
conducted through the:
Dorsal column on the side of the stimulation
Monitoring the posterior tibial nerve SSEPs is most appropriate in cerebrovascular
procedures involving which of the following arteries?
Anterior cerebral
Identification of wave V of the BAEP may require:
Decreasing stimulus intensity
In spinal surgery, the primary purpose of the popliteal fossa recording electrode is to:
Verify adequacy of stimulus
While performing a posterior tibial SSEP, hypothermia of the lower extremities is most
likely to cause:
Slowed peripheral conduction velocities
Which of the following peaks in tibial nerve SSEPs is most analogous to P14 of median
nerve SSEPs?
P31
During posterior fossa surgery, when BAEPs are used for monitoring brainstem
function, it is most important to:
Stimulate and record from the contralateral side
Which of the following cranial nerves is most appropriate to monitor during the resection
of a 4cm vestibular schwannoma?
Facial
During a carotid endarterectomy, what SSEP modality is recommended for monitoring
cerebral function?
Median
If the EEG is preserved during carotid endarterectomy surgery, it indicates:
Adequate cortical perfusion and oxygenation
Alternating current is used when checking electrode impedance to:
Avoid electrode polarization
Which of the following is most likely to cause 60hz contamination of EP waveforms in
the operating room?
Fluorescent lights
A postincision baseline recording is used to
Establish a standard for the patient
