CNIM APPARENTLY ON THE ACTUAL
TEST QUESTIONS AND ANSWERS WITH
SOLUTIONS 2024
An increase in stimulation intensity causes a linear increase of which of the following SSEP components?
1. N20
2. N45
3. P31
4. P37 - ANSWER 3. P31
Epidural electrodes are made of platinum because
1. It is the most durable metal
2. It is the lowest impedance metal
3. The chance of allergic reaction is eliminated
4. Other metals may become toxic when currents are applied - ANSWER 4. 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 10 mm gold disk, stimulus intensity is 20 mA, and stimulus duration is 100 usec. Which of the
following would most likely reduce the patients discomfort while maintaining adequate stimulation?
1. Increase stimulus duration
2. Use larger stimulating electrode
3. Use smaller stimulating electrode
4. Decrease stimulus intensity below motor threshold - ANSWER 2. Use larger stimulating electrode
Which of the following would enhance wave I of the BAEP?
1. Increase the rate
2. Increase the intensity
3. Decrease the analysis time
4. Decrease the number of repetitions - ANSWER 2. Increase the intensity
,In BAEPs, wave I can most easily be differentiated from cochlear microphonics based upon
1. Amplitude
2. Morphology
3. Click polarity
4. Absence in contralateral recording - ANSWER 3. Click polarity
What is the interstimulus interval of a 50 Hz click stimulus?
1. 0.02 msec
2. 0.20 msec
3. 0.50 msec
4. 20.00 msec - ANSWER 4. 20.00 msec
Contralateral masking should be used during BAEPs to
1. Help the patient relax
2. Enhance wave I amplitude
3. Separate the IV/V complex
4. Prevent crossover responses - ANSWER 4. Prevent crossover responses
The complete absence of a BAEP is most likely the result of
1. Sedation
2. Multiple sclerosis
3. Severe hearing loss
4. A normal age variant - ANSWER 3. Severe hearing loss
Identification of wave V of the BAEP may require
1. Tympanic electrodes
2. Bilateral stimulation
3. Decreasing stimulus intensity
,4. Use of a noncephalic reference - ANSWER 3. Decreasing stimulus intensity
In spinal surgery, the primary purpose of the popliteal fossa recording electrode is to
1. Verify adequacy of stimulus
2. Limit current spread
3. Confirm amplifier integrity
4. Provide evidence of a muscle twitch - ANSWER 1. Verify adequacy of stimulus
while performing a posterior tibial SSEP, hypothermia of the lower extremities is most likely to cause
1. Increased L3-P37 latency
2. Increased T12-P37 latency
3. Slowed peripheral conduction velocity
4. Abnormal prolongation of the P37-N45 complex - ANSWER 3. Slowed peripheral conduction velocity
Which of the following peaks in tibial nerve SSEPs is most analogous to P14 of median nerve SSEP?
1. N20
2. N34
3. P31
4. P37 - ANSWER 3. P31
Which of the following devices measures electrode resistance?
1. Ammeter
2. Ohmmeter
3. Voltmeter
4. Photometer - ANSWER 2. Ohmmeter
If an evoked potential has a voltage of 10 uV and the associated noise has a voltage of 50 uV, what is the
signal-to-noise ratio after 100 averaged responses?
1. 1:1
, 2. 1:2
3. 2:1
4. 5:1 - ANSWER 3. 2:1
To display median nerve SSEP response as an upward deflection, which of the following must be known?
1. Waveform polarity and latency of the response
2. Waveform polarity and polarity convention of the amplifier inputs
3. Polarity convention of amplifier inputs and amplitude of the response
4. Latency of the response and polarity convention of the amplifier inputs - ANSWER 2. Waveform
polarity and polarity convention of the amplifier inputs
If an amplifier is rated as having 120 dB common mode rejection ratio, which of the following ratios of
in-phase to out-of-phase signals would be expected?
1. 10,000:1
2. 100,000:1
3. 500,000:1
4. 1,000,000:1 - ANSWER 4. 1,000,000:1
Which of the following cranial nerves innervated the extraocular muscles?
1. Optic
2. Facial
3. Abducens
4. Trigeminal - ANSWER 3. Abducens
Which of the following is an example of an SSEP far-field subcortical potential?
1. N20
2. N34
3. Erbs point
4. Popliteal fossa - ANSWER 2. N34
TEST QUESTIONS AND ANSWERS WITH
SOLUTIONS 2024
An increase in stimulation intensity causes a linear increase of which of the following SSEP components?
1. N20
2. N45
3. P31
4. P37 - ANSWER 3. P31
Epidural electrodes are made of platinum because
1. It is the most durable metal
2. It is the lowest impedance metal
3. The chance of allergic reaction is eliminated
4. Other metals may become toxic when currents are applied - ANSWER 4. 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 10 mm gold disk, stimulus intensity is 20 mA, and stimulus duration is 100 usec. Which of the
following would most likely reduce the patients discomfort while maintaining adequate stimulation?
1. Increase stimulus duration
2. Use larger stimulating electrode
3. Use smaller stimulating electrode
4. Decrease stimulus intensity below motor threshold - ANSWER 2. Use larger stimulating electrode
Which of the following would enhance wave I of the BAEP?
1. Increase the rate
2. Increase the intensity
3. Decrease the analysis time
4. Decrease the number of repetitions - ANSWER 2. Increase the intensity
,In BAEPs, wave I can most easily be differentiated from cochlear microphonics based upon
1. Amplitude
2. Morphology
3. Click polarity
4. Absence in contralateral recording - ANSWER 3. Click polarity
What is the interstimulus interval of a 50 Hz click stimulus?
1. 0.02 msec
2. 0.20 msec
3. 0.50 msec
4. 20.00 msec - ANSWER 4. 20.00 msec
Contralateral masking should be used during BAEPs to
1. Help the patient relax
2. Enhance wave I amplitude
3. Separate the IV/V complex
4. Prevent crossover responses - ANSWER 4. Prevent crossover responses
The complete absence of a BAEP is most likely the result of
1. Sedation
2. Multiple sclerosis
3. Severe hearing loss
4. A normal age variant - ANSWER 3. Severe hearing loss
Identification of wave V of the BAEP may require
1. Tympanic electrodes
2. Bilateral stimulation
3. Decreasing stimulus intensity
,4. Use of a noncephalic reference - ANSWER 3. Decreasing stimulus intensity
In spinal surgery, the primary purpose of the popliteal fossa recording electrode is to
1. Verify adequacy of stimulus
2. Limit current spread
3. Confirm amplifier integrity
4. Provide evidence of a muscle twitch - ANSWER 1. Verify adequacy of stimulus
while performing a posterior tibial SSEP, hypothermia of the lower extremities is most likely to cause
1. Increased L3-P37 latency
2. Increased T12-P37 latency
3. Slowed peripheral conduction velocity
4. Abnormal prolongation of the P37-N45 complex - ANSWER 3. Slowed peripheral conduction velocity
Which of the following peaks in tibial nerve SSEPs is most analogous to P14 of median nerve SSEP?
1. N20
2. N34
3. P31
4. P37 - ANSWER 3. P31
Which of the following devices measures electrode resistance?
1. Ammeter
2. Ohmmeter
3. Voltmeter
4. Photometer - ANSWER 2. Ohmmeter
If an evoked potential has a voltage of 10 uV and the associated noise has a voltage of 50 uV, what is the
signal-to-noise ratio after 100 averaged responses?
1. 1:1
, 2. 1:2
3. 2:1
4. 5:1 - ANSWER 3. 2:1
To display median nerve SSEP response as an upward deflection, which of the following must be known?
1. Waveform polarity and latency of the response
2. Waveform polarity and polarity convention of the amplifier inputs
3. Polarity convention of amplifier inputs and amplitude of the response
4. Latency of the response and polarity convention of the amplifier inputs - ANSWER 2. Waveform
polarity and polarity convention of the amplifier inputs
If an amplifier is rated as having 120 dB common mode rejection ratio, which of the following ratios of
in-phase to out-of-phase signals would be expected?
1. 10,000:1
2. 100,000:1
3. 500,000:1
4. 1,000,000:1 - ANSWER 4. 1,000,000:1
Which of the following cranial nerves innervated the extraocular muscles?
1. Optic
2. Facial
3. Abducens
4. Trigeminal - ANSWER 3. Abducens
Which of the following is an example of an SSEP far-field subcortical potential?
1. N20
2. N34
3. Erbs point
4. Popliteal fossa - ANSWER 2. N34
