CNIM Intraoperative Final Exam and
All Correct Answers Graded A+ 2026
Updated.
For preoperative posterior tibial SSEPs, which of the following would be the best ipsilateral
location for the ground electrode? - Answer Calf
If nasion to inion measures 40 cm, the distance between Fpz and Cz is what? - Answer 16 cm
To avoid a false positive, the baseline is best taken - Answer pre-incision.
During a discussion with the anesthesiologist prior to starting IONM on a spinal correction
surgery, you are informed the MDA plans to use volatile anesthetics. Rank the volatile
anesthetic agents per their MAC values (highest to lowest). - Answer Desflurane >
Sevoflurane > Isoflurane
According to ACNS guidelines, baseline data should be established: - Answer Following
positioning, but prior to surgical manipulation of nervous system
Nitrous Oxide - Answer Decreases waveform amplitude and increases the latency of cortical
responses
The highest percentage of EEG changes seen after cross clamping during CEA happen within
______ of the cross clamp being placed. - Answer two minutes
Which of the following can increase SSEP amplitudes? - Answer Etomidate
During the monitoring of a selective dorsal rhizotomy, what muscle is critical to monitor? -
Answer Anal Sphincter
If there is a 60 Hz interference in all channels when recording preoperative median nerve SSEPs,
which of the following electrodes should be adjusted first? - Answer Ground electrode
Median nerve peripheral conduction between the brachial plexus and cervical cord is the time
measured from: - Answer EP-N13
Which structure is at risk during an XLIF procedure? - Answer Lumbar plexus
,In recording electrocochleograms, it is best to stimulate using - Answer rarefaction or
condensation clicks.
Which of the following is most likely to cause electrical interference for evoked potential
waveforms in the operating room? - Answer Electrocautery
Which of the following would most likely be normal in the lower extremity SSEP of a patient
with a dorsal column lesion? - Answer Popliteal Fossa Response
1 MAC of Desflurane is equivalent to a concentration of: - Answer 0.06
During a median nerve preoperative study, a patient has discomfort at the wrist. Stimulating
electrodes are 10mm gold disk, stimulus intensity is 20 mA, and stimulus duration is 100
microseconds. Which of the following would most likely reduce the patients discomfort while
maintaining adequate stimulation? - Answer Decrease the stimulus intensity to motor
threshold
To4 is used to determine which of the following values? - Answer level of neuromuscular
blockage present
Which of the following is a common complication of microvascular decompression of cranial
nerve VIII? - Answer Hearing loss
Ischemic injury of the anterior spinal artery will affect which modality first? - Answer tcMEPs
Extreme cerebellar retraction during CPA tumor surgery likely results in: - Answer Loss of all
waves due to vascular compromise
Wave I of the Brainstem Auditory Evoked Potential (BAEP) has a typical post-stimulus latency of -
Answer 2 ms
According to ACNS Guidelines, what is the recommended placement of the ground for a cervical
procedure? - Answer Forearm
If the brachial plexus is at risk for compression due to patient positioning, the technologist,
surgeon and neurophysiologist should discuss adding which SSEP modality to the surgical plan?
- Answer Ulnar Nerve
Which of the following is most likely an anesthetic change seen in spine cases? - Answer
Changes in cortical responses in bilateral UE and LE SSEPs
, Which BAER click polarity eliminates the cochlear microphonic? - Answer Alternating
In identification of phase reversal for sensory-motor localization, which response is pre-central
and which is post-central? - Answer P22, N20
Between which contacts on this 2 x 4 grid is a phase reversal apparent? - Answer Between
contacts G3 and G4.
Which of the following is a critical surgical event? - Answer Resecting of tumor fragments
during acoustic neuroma resection
What is the response indicated by the line marked "X"? - Answer P31
When deciding between an 8ft and 20ft connector cable for a 32-channel system, why is the 8ft
cable preferred? - Answer Decreased electrical interference
Depolarizing agent: - Answer Succinylcholine
Which of the following improves the signal-to-noise ratio by the square root of the number of
responses added? - Answer Signal averaging
While monitoring SSEP and EEG, in what timeframe would you expect vascular clamp-related
EEG changes to occur during a carotid endarterectomy? - Answer 1 minute
Changes in Wave III-V interpeak interval of the Brainstem Auditory Evoked Potential (BAEP) is
used to identify changes in - Answer Brainstem function
Recording of median nerve SSEPs during carotid endarterectomy is a useful adjunct to EEG for
detecting - Answer ischemia from the middle cerebral artery.
You are monitoring a right Carotid Endarterectomy (CEA). If the patient does not have adequate
collateral flow, what changes will you see when the surgeon clamps the artery? - Answer
Right EEG slowing and Left Upper cortical SSEP decrease in amplitude
Which TcMEP montage may be beneficial during a posterior fossa procedure when the patient is
in the sitting position and intracranial air over the hemispheric convexities can interfere with
coronal transcranial electrial stimulation? - Answer CZ-FZ
All Correct Answers Graded A+ 2026
Updated.
For preoperative posterior tibial SSEPs, which of the following would be the best ipsilateral
location for the ground electrode? - Answer Calf
If nasion to inion measures 40 cm, the distance between Fpz and Cz is what? - Answer 16 cm
To avoid a false positive, the baseline is best taken - Answer pre-incision.
During a discussion with the anesthesiologist prior to starting IONM on a spinal correction
surgery, you are informed the MDA plans to use volatile anesthetics. Rank the volatile
anesthetic agents per their MAC values (highest to lowest). - Answer Desflurane >
Sevoflurane > Isoflurane
According to ACNS guidelines, baseline data should be established: - Answer Following
positioning, but prior to surgical manipulation of nervous system
Nitrous Oxide - Answer Decreases waveform amplitude and increases the latency of cortical
responses
The highest percentage of EEG changes seen after cross clamping during CEA happen within
______ of the cross clamp being placed. - Answer two minutes
Which of the following can increase SSEP amplitudes? - Answer Etomidate
During the monitoring of a selective dorsal rhizotomy, what muscle is critical to monitor? -
Answer Anal Sphincter
If there is a 60 Hz interference in all channels when recording preoperative median nerve SSEPs,
which of the following electrodes should be adjusted first? - Answer Ground electrode
Median nerve peripheral conduction between the brachial plexus and cervical cord is the time
measured from: - Answer EP-N13
Which structure is at risk during an XLIF procedure? - Answer Lumbar plexus
,In recording electrocochleograms, it is best to stimulate using - Answer rarefaction or
condensation clicks.
Which of the following is most likely to cause electrical interference for evoked potential
waveforms in the operating room? - Answer Electrocautery
Which of the following would most likely be normal in the lower extremity SSEP of a patient
with a dorsal column lesion? - Answer Popliteal Fossa Response
1 MAC of Desflurane is equivalent to a concentration of: - Answer 0.06
During a median nerve preoperative study, a patient has discomfort at the wrist. Stimulating
electrodes are 10mm gold disk, stimulus intensity is 20 mA, and stimulus duration is 100
microseconds. Which of the following would most likely reduce the patients discomfort while
maintaining adequate stimulation? - Answer Decrease the stimulus intensity to motor
threshold
To4 is used to determine which of the following values? - Answer level of neuromuscular
blockage present
Which of the following is a common complication of microvascular decompression of cranial
nerve VIII? - Answer Hearing loss
Ischemic injury of the anterior spinal artery will affect which modality first? - Answer tcMEPs
Extreme cerebellar retraction during CPA tumor surgery likely results in: - Answer Loss of all
waves due to vascular compromise
Wave I of the Brainstem Auditory Evoked Potential (BAEP) has a typical post-stimulus latency of -
Answer 2 ms
According to ACNS Guidelines, what is the recommended placement of the ground for a cervical
procedure? - Answer Forearm
If the brachial plexus is at risk for compression due to patient positioning, the technologist,
surgeon and neurophysiologist should discuss adding which SSEP modality to the surgical plan?
- Answer Ulnar Nerve
Which of the following is most likely an anesthetic change seen in spine cases? - Answer
Changes in cortical responses in bilateral UE and LE SSEPs
, Which BAER click polarity eliminates the cochlear microphonic? - Answer Alternating
In identification of phase reversal for sensory-motor localization, which response is pre-central
and which is post-central? - Answer P22, N20
Between which contacts on this 2 x 4 grid is a phase reversal apparent? - Answer Between
contacts G3 and G4.
Which of the following is a critical surgical event? - Answer Resecting of tumor fragments
during acoustic neuroma resection
What is the response indicated by the line marked "X"? - Answer P31
When deciding between an 8ft and 20ft connector cable for a 32-channel system, why is the 8ft
cable preferred? - Answer Decreased electrical interference
Depolarizing agent: - Answer Succinylcholine
Which of the following improves the signal-to-noise ratio by the square root of the number of
responses added? - Answer Signal averaging
While monitoring SSEP and EEG, in what timeframe would you expect vascular clamp-related
EEG changes to occur during a carotid endarterectomy? - Answer 1 minute
Changes in Wave III-V interpeak interval of the Brainstem Auditory Evoked Potential (BAEP) is
used to identify changes in - Answer Brainstem function
Recording of median nerve SSEPs during carotid endarterectomy is a useful adjunct to EEG for
detecting - Answer ischemia from the middle cerebral artery.
You are monitoring a right Carotid Endarterectomy (CEA). If the patient does not have adequate
collateral flow, what changes will you see when the surgeon clamps the artery? - Answer
Right EEG slowing and Left Upper cortical SSEP decrease in amplitude
Which TcMEP montage may be beneficial during a posterior fossa procedure when the patient is
in the sitting position and intracranial air over the hemispheric convexities can interfere with
coronal transcranial electrial stimulation? - Answer CZ-FZ
