CNIM Frequent Miss

A patient with a body temperature of 30 degrees C will have:

A- Decreased latencies
B- Decreased latencies, decreased amplitudes
C- Increased latencies
D- Increased latencies, decreased amplitudes

C- Increased latencies

The P31 response to posterior tibial nerve stimulation:

A- Is recordable over a generalized region of scalp
B- Is best recorded by an electrode placed at CS5
C- Is generated by the thalamus
D- Reflects post-synaptic activity in the cervical spinal cord

A- Is recordable over a generalized region of scalp

Why are SSEP and MEP used simultaneously?

A- Because MEPs indicate spinothalamic tract function
B- Spinal cord damage can occur in only one tract causing loss of MEP but not SSEP
C- Because SSEP monitoring alone is not very sensitive to changes in spinal cord function
D- All of the above

B- Spinal cord damage can occur in only one tract causing loss of MEP but not SSEP

If the bin width of you system is 20 μS, then the highest frequency signal that can be resolved is:

A- 50 KHz
B- 100 KHz
C- 25 KHz
D- 20 KHz

C- 25 KHz

EEG will most likely disappear at what body temperature?

A- 16 º C
B- 36º C
C- 23 º C
D- 28º C

A- 16 º C

What will be the frequency of a signal if in a 30 mS sweep the interval between each cycle of the signal is 0.03 mS?

A- 3333 KHz
B- 33 KHz
C- 333 KHz
D- 3 KHz

B- 33 KHz

According to the Guidelines what is the acceptable sweep for ABR's?

A- 20-30 msec
B- 10-15 msec
C- 5 msec
D- 25 msec

B- 10-15 msec

You do not want to use a power extension cord because:



A- It is a fire hazard
B- It will mean that more current could be delivered to the patient if the ground fails
C- It may interfere with the operation of other devices in the operating room
D- It will increase your risk of ground leakage

D- It will increase your risk of ground leakage

Which of the following is a barbiturate?

A- Methohexital
B- Remifentanyl
C- Nitrous Oxide
D- Curare

A- Methohexital

Tinel's sign

A- Cortex
B- Spinal cord
C- Muscle
D- Peripheral nerve

D- Peripheral nerve

Cortel-Dubousset instrumentation involves which of the following?

A- Derotation
B- Distraction
C- Sublaminar wires
D- Intervertebral diskectomy

A- Derotation

A loss of SSEP response would most likely occur ________ to the surgical site.

A- Anterior
B- Caudal
C- Posterior
D- Rostral

D- Rostral

What is the noise reduction technique that best reduces EKG artifact?

A- Common mode rejection
B- Averaging
C- Artifact reject
D- Hicut filter

C- Artifact reject

When you have a salt bridge you will:

A- Be able to stimulate the underlying nerve better
B- Create a lethal pathway for current
C- Max out your impedances
D- Have difficulty stimulating the underlying nerve

D- Have difficulty stimulating the underlying nerve

All of the following are benefits of EEG monitoring during carotid endarterectomy except:

A- Selective shunting
B- Detection of hypoxia
C- Detection of occlusion-associated ischemia
D- Detection of heparin dosage

D- Detection of heparin dosage

If you have a 5 μV signal amplitude and a 20 μV noise amplitude, how many averages would you need to get a signal to noise ratio of 2:1?

A- 100
B- 20
C- 64
D- 16

C- 64

Which component would be most affected by a tumor by the intersection of the spinal cord and medulla?

A- N13
B- P31
C- N20
D- EP

A- N13

What type of electrode is recommended for monitoring facial nerve?

A- Cueva nerve electrode
B- Ring electrode
C- Surface
D- Hook-wire

D- Hook-wire

The stimulation rate is determined by the:

A- Stimulus intensity
B- Nerve conduction velocity
C- Analysis time
D- Number of stimulations

C- Analysis time

What is the MAXIMUM time in which to expect EEG changes following cross clamping of the carotid?

A- 30 seconds
B- 5 minutes
C- 2 minutes
D- 1 minute

C- 2 minutes

The most appropriate ABR interstimulus interval is:

A- 20 mS
B- 0.02 mS
C- 50 mS
D- 5 mS

A- 20 mS

Which of the following is most affected by halogenated agents?

A- Auditory brainstem response
B- Posterior tibial cortical potential
C- Median nerve subcortical response
D- Lumbar response to PTN stimulation

B- Posterior tibial cortical potential

The appropriate analysis time for ABRs is:

A- 100 mS
B- 50 mS
C- 15 mS
D- 20 mS

C- 15 mS

During electrocautery we should:

A- Pause recording
B- Continue to average and watch raw traces
C- Run impedances to let the amp desaturate
D- Request the surgeon to stop

A- Pause recording

Compound muscle action potentials to transcranial electric stimulation are susceptible to:

A- Pavulon
B- Isoflurane
C- Propofol
D- All of the above

D- All of the above

Stimulating the median nerve at the wrist yields an Erb's point response at 10 mS and an NCV of 60 m/S. What is the distance between the cathode and the Erb's point recording electrode?

A- Cannot be determined with this information
B- 60 cm
C- 50 cm
D- 166 cm

B- 60 cm

Excessive cerumen may cause:

A- Increased I-V interpeak latencies
B- Absence of wave V
C- Absence of the BAER
D- Increased I-III interpeak latencies

C- Absence of the BAER

To protect the patient from inadvertent shock during power ‐ on and power ‐ off, the maximum leakage current through patient leads should be

A- 10 milliamps
B- 1 microamp
C- 100 microamps
D- 10 microamps

D- 10 microamps

When the number of trial rejections increases during electrocautery, the best action is:

A- Pause data collection
B- Inform surgeon
C- Increase number of sweeps
D- Increase stimulus intensity

A- Pause data collection

Cardiac activity appears on the CSA/DSA display as:

A- beta activity
B- alpha activity
C- delta activity
D- intermittent theta

C- delta activity

In general, filter settings for SEP recordings

A- can be narrower for cortical than peripheral responses
B- should always be 30 ‐ 3000 Hz
C- should always include 60 Hz band pass filters
D- can be narrower for peripheral than cortical responses

A- can be narrower for cortical than peripheral responses

Transcranial Magnetic Evoked Potentials are preferred over Transcranial Electric motor evoked potentials for intraoperative monitoring because:

A- They are not preferred for intraoperative monitoring
B- They require less rigorous anesthetic management
C- They are painless
D- There is no risk of seizures

A- They are not preferred for intraoperative monitoring

The agent least depressing SEP monitoring is probably

A- pancuronium
B- vecuronium
C- ketamine
D- sevoflurane

C- ketamine

What is the main advantage of asynchronous bilateral stimulation?

A- Less patient movement
B- Reduction of stimulus artifact
C- Faster data acquisition
D- Differentiation of local vs. systemic effects

D- Differentiation of local vs. systemic effects

Movement artifact on the EEG is most likely to produce

A- slow EEG wave activity
B- fast EEG wave activity
C- asymmetrical activity at 60 Hz
D- burst‐suppression

A- slow EEG wave activity

Which of the following could cause a false negative in a T10 surgery?

A- Synchronous PTN stimulation
B- Asynchronous PTN stimulation
C- Asynchronous peroneal stimulation
D- Asynchronous MN stimulation

D- Asynchronous MN stimulation

Vasospasm of AICA will result in

A- Increased inter peak waves III-V ABR latencies
B- Complete loss of all ABR waves with exception of cochlear microphonic
C- Loss of waves III-V
D- Increased inter peak waves III-V ABR latencies

B- Complete loss of all ABR waves with exception of cochlear microphonic

EEG waves with a frequency of 5 Hz can be classified as what type of EEG?

A- delta activity
B- beta activity
C- alpha activity
D- theta activity

D- theta activity

The type of pathology that would change the ABR interpeak latencies the greatest is

A- pathology in the middle ear
B- pathology in the cochlea
C- pathology of the VIII cranial nerve
D- pathology of the XII cranial nerve

C- pathology of the VIII cranial nerve

An average individual sheds skin at the rate of approximately:

A- 40 ‐ 400 cells per minute
B- 10 ‐ 40 cells per minute
C- 400 ‐ 4000 cells per minute
D- 4000 ‐ 10,000 cells per minute

D- 4000 ‐ 10,000 cells per minute

The major positive ion inside the cell or axon is:

A- Na
B- Ca
C- K
D- H2O

C- K

The recommended filter setting for the facial nerve CMAP are:

A- 1 - 15 kHz
B- 10 - 1.5 kHz
C- 10 - 15 kHz
D- 1 - 1.5 kHz

D- 1 - 1.5 kHz

The D ‐ wave should be recorded:

A- Rostral to the surgical site
B- From the distal limb muscles
C- Caudal to the surgical site
D- From the proximal limb muscles

C- Caudal to the surgical site

Isola rod system

A- Neurosurgical
B- Vascular
C- Psychiatric
D- Orthopedic

D- Orthopedic

The duration of a monophasic, rectangular pulse used for somatosensory stimulation should be

A- 0.5 ms
B- 1 ms
C- 0.2 ms
D- 0.05 ms

C- 0.2 ms

If the patients threshold is 25 dB and the stimulator is set to 85 dB, then the intensity is

A- 110 dB SL
B- 60 dB SL
C- 60 dB HL
D- 85 dB SL

B- 60 dB SL

The difference between the voltages in input 1 and input 2 will make the display of the amplifier move:

A- in a sinusoidal pattern
B- either up or down
C- down
D- up

B- either up or down

The motor cervical spine C5 nerve root produces:

A- Elbow extension
B- Arm abduction
C- wrist flexion
D- wrist extension

B- Arm abduction

Which of the following is associated with loss of proprioception?

A- Tourette's syndrome
B- Tinel's sign
C- Anterior cord syndrome
D- Romberg's sign

D- Romberg's sign

A patient who does not have collateral blood supply during an endarterectomy can suffer a postoperative deficit if the lack of blood flow is not resolved in less than

A- 10 min.
B- 55 min.
C- 30 min.
D- 45 min.

A- 10 min.

Which type of surgery is least likely to require EMG monitoring of the external anal sphincter?

A- surgery of the sacral plexus involving S2, S3 and S4
B- excision of masses of the cauda equina
C- lipomyelomeningocele
D- herniated L5 disc

D- herniated L5 disc

The gain of an amplifier, set to give an output signal of 1 volt for an input signal of 10 microV, is

A- 100,000
B- 10,000
C- 1,000
D- 100

A- 100,000

All of the following are benefits of EEG monitoring during carotid endarterectomy except:

A- detection of heparin dosage
B- detection of hypoxia
C- detection of occlusion-associated ischemia
D- detection of hypotension

A- detection of heparin dosage

The common peroneal nerve arises at the superior angle of the popliteal fossa from the



A- internal popliteal nerve
B- sciatic nerve
C- superior femoral nerve
D- superior tibial nerve

B- sciatic nerve

How many waves of a 60 Hz signal should you see in a 100 msec sweep?

A- 4
B- 6
C- 20
D- 12

B- 6

Sensation Level (SL) is defined by:

A- The average hearing threshold of a normal population
B- A measure of the ambient pressure
C- The absolute sound pressure relative to atmospheric pressure
D- An individual's hearing threshold

D- An individual's hearing threshold

For the intraoperative recording of EEG, the impedance of a scalp electrode should range from:

A- 1,000 to 5,000 ohms
B- 5,000 to 10,000 ohms
C- 500 to 1,000 ohms
D- 250 to 500 ohms

A- 1,000 to 5,000 ohms

With a sampling rate of 10 kHz the shortest sine wave resolved would be

A- 2 msec
B- 0.4 msec
C- 0.2 msec
D- 0.02 msec

C- 0.2 msec

At the stage of surgical anesthesia, propofol affects the BAEP by

A- causing very minimal changes
B- decreasing the amplitude in all waveforms
C- increasing the latencies of waves I, III, and V without changing their amplitudes
D- abolishing all waveforms

C- increasing the latencies of waves I, III, and V without changing their amplitudes

In posterior fossa craniotomy surgery for a large tumor with unilateral hearing loss, the appropriate modalities to monitor would be:

A- Ipsilateral BAEP and facial nerve
B- Contralateral BAEP, median nerve SSEP and facial nerve
C- Facial nerve and contralateral median nerve
D- Ipsilateral BAEP

B- Contralateral BAEP, median nerve SSEP and facial nerve

The sensitivity setting on an amplifier set to produce a vertical deflection of 1 cm with an input of 10 mV is

A- 10 mV/mm
B- 20 mV/cm
C- 1 mV/cm
D- 1 mV/mm

D- 1 mV/mm

Vascular malformations of the posterior fossa associated with hemifacial spasm and facial paresis may cause

A- BAEP abnormalities if the auditory cortex is involved
B- BAEP latency abnormalities
C- increased amplitudes if tubal inserts are used for stimulation
D- a loss of Wave I on the BAEP

B- BAEP latency abnormalities

What would be the effect of fluid in the external auditory canal?

A- Increased I-V latency
B- Decreased wave V amplitude
C- Increased wave amplitudes
D- Increase of absolute latencies

D- Increase of absolute latencies

Which of the following are acceptable filter settings for recording BAEPs:

A- 1 - 1000 Hz
B- 250 - 2500 Hz
C- 500 - 5000 Hz
D- 10 - 2500 Hz

D- 10 - 2500 Hz

What bandpass filter should be used to record CMAPs for facial nerve?

A- 10 to 500 Hz
B- 1 to 500 Hz
C- 10 to 1500 Hz
D- 300 to 16000 Hz

C- 10 to 1500 Hz

An unstable blood pressure during SSEP monitoring in the OR affects cortical EPs resulting in

A- fluctuating latencies
B- fluctuating amplitudes and latencies
C- minimal changes if the body temperature is maintained above 32° C
D- fluctuating amplitudes

D- fluctuating amplitudes

Changing the low cut filter of a BAEP from 100 to 200 Hz will result in:

A- No change
B- Increased response latency
C- Increased response amplitude
D- Decreased response latency

D- Decreased response latency

Bipolar electrodes are used for localization of:

A- Far field signals
B- Signals via phase reversal
C- Phase changes in instrument
D- Decreased common mode rejection

B- Signals via phase reversal

The suggested rate of stimulation for intraoperative posterior tibial nerve evoked potential monitoring is:

A- 2 to 10 per second
B- 20 to 30 per second
C- 10 to 20 per second
D- 30 to 40 per second

A- 2 to 10 per second

Loss of BAEPs following drilling of the internal auditory canal is most likely due to:

A- Transection of the auditory nerve
B- Compression of the brainstem
C- Disruption of the cochlear blood supply
D- Ipsilateral masking effect

C- Disruption of the cochlear blood supply

For stimulation in motor evoked potential (MEP) studies, the anode should be placed:

A- Caudal to the cathode
B- Medial to the cathode
C- Lateral to the cathode
D- Rostral to the cathode

D- Rostral to the cathode

Which component would be most affected by a tumor by where the spinal cord and medulla intersect?

A- P31
B- 4.234
C- N13
D- EP

C- N13

Which of the following anesthetic agents will obliterate the transcranial electric motor evoked potential?

A- Fentanyl
B- Propofol
C- Desflurane
D- Nitrous oxide

C- Desflurane

What would you see with Sodium Amytal?

A- Decreased amplitude, increased latency
B- Decreased latency
C- Increased amplitude
D- No effect

A- Decreased amplitude, increased latency

Fentanyl infusion will:

A- Have no affect on amplitude or latency
B- Decrease amplitude only
C- Increase latency and decrease amplitude
D- Increase amplitude and increase latency

C- Increase latency and decrease amplitude

The pneumatic drill has which of the following effects on BAEPs?

A- Increases I-III interpeak latency
B- None
C- Prolongs wave V
D- Increases III-V interpeak latency

C- Prolongs wave V

How do you monitor a dorsal rhizotomy?

A- Stimulus testing of sensory rootlets
B- TCMEP
C- Free‐run EMG
D- SSEP

A- Stimulus testing of sensory rootlets

Which of the following causes 60 Hz contamination of evoked potentials in the OR?

A- Pneumatic drill
B- Fluorescent lights
C- Bipolar electrocautery
D- Twitch monitor

B- Fluorescent lights

Which of the following would most affect the ability to record BAEPs?

A- Drill
B- Coagulator
C- Anesthetic agent
D- Retractor

B- Coagulator

The length of the patient's limb directly influences:

A- Interpeak latencies
B- Response amplitude
C- Absolute peak latencies
D- Amplitude ratio

C- Absolute peak latencies

What is an appropriate filter for a short latency SSEP cortical response?

A- 0.1‐250 Hz
B- 10‐3000 Hz
C- 100‐1000 Hz
D- 1‐100 Hz

B- 10‐3000 Hz

When monitoring brainstem auditory evoked potentials intraoperatively, it is recommended to warn the surgeon when an increase of which of the following occurs?

A- The latency of wave I of 1 millisecond
B- The latency of wave V of less than 1.0 millisecond
C- The latency of wave V of 1.0 millisecond or greater
D- The inter peak latency of I-V of 1.0 millisecond or less

C- The latency of wave V of 1.0 millisecond or greater

Which of the following opposes any change in current?

A- Inductance
B- Capacitance
C- Resistance
D- Impedance

A- Inductance

Horizontal Dipole

A- P14
B- N34
C- N18
D- Erb's point

A- P14

Why is it important when recording SSEPs to have electrodes made out of similar metals?

A- To ensure adequate stimulation
B- To avoid delivering toxic chemicals
C- In order to have the same time constant
D- To avoid electrode polarization

D- To avoid electrode polarization

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?

A- 1,000,000:1
B- 500,000:1
C- 10,000:1
D- 100,000:1

A- 1,000,000:1

If the internal auditory canal is occluded, what will be the result?

A- Decrease in I-V interpeak interval
B- Change in III-V interpeak interval
C- Decrease of wave V amplitude
D- Prolongation of all waves

C- Decrease of wave V amplitude

How do you increase your horizontal resolution?

A- Decrease analysis time
B- Increase Highcut filter
C- Increase stim rate
D- Decrease data points

A- Decrease analysis time

The most appropriate ABR interstimulus interval is:

A- 5 mS
B- 20 mS
C- 50 mS
D- 0.02 mS

B- 20 mS

Vascular compromise of the posterior cerebral artery will most likely have what effect on the MN SEP?

A- Loss of Erb's point
B- Loss of P14/N18
C- Loss of N13
D- Loss of N20/P22

B- Loss of P14/N18

While performing a posterior tibial SSEP, hypothermia of the lower extremities is most likely to cause

A- Increased L3‐P37 latency
B- Abnormal prolongation of the P37‐N45 complex
C- Slowed peripheral conduction velocity
D- Increased T12‐P37 latency

C- Slowed peripheral conduction velocity

The stimulation rate is determined by the

A- Stimulus intensity
B- Number of stimulations
C- Analysis time
D- Nerve conduction velocity

C- Analysis time

Which of the following can improve horizontal resolution?

A- Increasing the stimulation rate
B- Increasing the HFF
C- Decreasing the number of data points
D- Decreasing the analysis time

D- Decreasing the analysis time

A pneumatic drill would introduce what kind of artifact?

A- 60 Hz
B- 1 Hz
C- 3000 Hz
D- 500 Hz

D- 500 Hz

If you had a lesion just after the right ventral posterolateral nucleus, how would that effect SSEP's?



A- Absent right cortical SSEP
B- Absent left subcortical
C- Absent left cortical SSEP
D- Absent right subcortical

C- Absent left cortical SSEP

What modality should be offered for a cerebral tumor just behind the central sulcus at the midline?



A- Cortical mapping with direct cortical stimulation for arm motor responses
B- Upper and lower extremity TCMEP
C- Electrocorticography
D- Cortical mapping with direct cortical stimulation for leg motor responses

D- Cortical mapping with direct cortical stimulation for leg motor responses

Stimulation of median nerve and direct cortical recording for phase reversal is used to locate



A- Sensorimotor cortex
B- Broca's area
C- Wernicke's area
D- Central Sulcus

D- Central Sulcus

When is it most appropriate to alert the surgeon of a problem with the monitoring?



A- After a loss of 55% amplitude
B- After a loss of 30% and 5% latency
C- When any change occurs
D- After all waveforms are lost

A- After a loss of 55% amplitude

When recording scalp SSEPs, the signal is transmitted primarily through the?



A- Spinothalamic pathway contralateral to stimulation
B- Dorsal column ipsilateral to stimulation
C- Spinothalamic pathway ipsilateral to stimulation
D- Dorsal column contralateral to stimulation

B- Dorsal column ipsilateral to stimulation

Anastomosis



A- Connection between two structures
B- Peripheral neuropathy
C- Crossing fibers
D- Vertebral displacement

A- Connection between two structures