CNIM STUDY GUIDE FULL QUESTIONS
WITH DETAILED ANSWERS
●● 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
WITH DETAILED ANSWERS
●● 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
