CNIM Exam 3

If the VIIIth nerve were transected, you would get

A- No change
B- Increased I-III latency
C- Loss of wave III - V
D- Absence of all waves I-V

D- Absence of all waves I-V

Epidural electrodes should be placed:

A- Inside the spinal cord
B- Between the dura and the spinal cord
C- Above the dura
D- Above the lamina

C- Above the dura

Early changes to CMAPs, during the exposure of CN VII, are most likely due to:

A- an increase in inhalation agents
B- severe blood loss
C- heating from the electrical cautery device
D- changes in the patient's state of consciousness

C- heating from the electrical cautery device

During posterior fossa exploration for tic douloureaux, the monitoring of median nerve SSEPs will demonstrate the:

A- location of the trigeminal nerve
B- effect of retractor placement on the cochlear and vestibular nerves
C- integrity of the somatosensory system traversing brainstem structures
D- integrity of the brainstem

C- integrity of the somatosensory system traversing brainstem structures

The effect of severe hypotension on the evoked potential includes

A- a decrease in amplitude and variable changes in latency
B- variable changes in amplitude and an increase in latency
C- an increase in amplitude and a decrease in latency
D- a decrease in amplitude and an increase in latency

D- a decrease in amplitude and an increase in latency

Aliasing is the result of:

A- Low input impedance
B- Sampling above the Nyquist frequency
C- Sampling below the Nyquist frequency
D- High recording electrode impedance

C- Sampling below the Nyquist frequency

Lhermitte's Sign

A- Bell's palsy
B- Patellar reflex
C- Optic tract lesion
D- Spinal cord lesion

D- Spinal cord lesion

Alternating clicks can be used to:

A- Eliminate stimulus artifact
B- Enhance the cochlear microphonic
C- Evaluate left and right sides simultaneously
D- Increase wave I amplitude

A- Eliminate stimulus artifact

While stimulating cranial nerve VII, a bipolar type stimulator has an advantage over a monopolar stimulator by:

A- being less expensive
B- presenting less risk of damage to the neural tissue
C- requiring less current
D- having greater specificity

D- having greater specificity

The input impedance of a differential amplifier must be at least:

A- 10 megaohms
B- <10 megaohms
C- 100 megaohms
D- <5 Kohms

C- 100 megaohms

A constant voltage stimulator

A- maintains a constant voltage of 100 volts
B- maintains a current level of 10 mA
C- varies the current in order to maintain a preset voltage level
D- varies the output in order to maintain a preset current level

C- varies the current in order to maintain a preset voltage level

What muscle would you monitor for EMG activity for cranial nerve XII?

A- Trapezius
B- Tongue
C- Frontalis
D- Masseter

B- Tongue

Evoked potential systems must be calibrated a MINIMUM of once every:

A- One year
B- Periodically as needed
C- Two years
D- Six months

D- Six months

A patitent is admitted to the operating room diagnosed with a burst fracture of the first lumbar vertebra. The most appropriate nerve(s) to monitor would be the:

A- posterior tibial and auditory nerves
B- cauda equina
C- median and ulnar nerves
D- posterior tibial and ulnar nerves

D- posterior tibial and ulnar nerves

EP waveforms contralateral to the surgical site are monitored to differentiate between

A- systemic changes and local manipulation
B- blood pressure and body temperature changes
C- anesthesia levels
D- artifact and grounding problems

A- systemic changes and local manipulation

Generally speaking, rate increases above 30 per second in BAEP studies:

A- will increase the latency and decrease the amplitude of the BAEP
B- have little or no effect on BAEP responses
C- will decrease wave V amplitude and increase wave I amplitude
D- will increase the amplitude of wave V

A- will increase the latency and decrease the amplitude of the BAEP

Which is the best anesthetic protocol to use for median nerve SSEP monitoring?

A- Fentanyl bolus injections
B- Fentanyl infusion
C- Midazolam infusion
D- Midazolam bolus injections

B- Fentanyl infusion

The effectis of Harrington rod distraction on the spinal cord can be tested by all of the following except:

A- The Stagnara wake-up test
B- Somatosensory EPs
C- Dorsal root stimulation
D- Motor EPs

C- Dorsal root stimulation

Electrodes embedded in a thin sheet of plastic material may be used for

A- electrocorticographic recordings
B- electrocochleographic recordings
C- electromechanical stimulation
D- electroretinographic recordings

A- electrocorticographic recordings

The ulnar nerve originates from nerve roots at:

A- C5 - C6
B- C6 - C7
C- C7 - T1
D- C7 - C8

C- C7 - T1

What is the most critical thing to document?

A- Important surgical events
B- Urine output
C- Blood pressure
D- Patient hematocrit

A- Important surgical events

A recommendation to minimize stimulus artifact while recording BAEPs intraoperatively is to

A- use rarefaction clicks
B- use larger sized headphones
C- use alternating clicks
D- decrease the impedance of your stimulating electrodes

C- use alternating clicks

All of the following are true of magnetic stimulation except:

A- An electrical stimulator is required to pace the stimulus
B- Pulses of current are delivered through a coil of wire
C- The stimulation is not perceived as painful
D- The magnetic field created causes movement in cortical neurons

A- An electrical stimulator is required to pace the stimulus

Of those patients who demonstrate significant EEG changes following cross clamping of the carotid, the majority of changes will
occur within:

A- 5 minutes
B- 2 minutes
C- 1 minute
D- 20 seconds

D- 20 seconds

The ISOLA type of spinal instrumentation usually involves:

A- The placement of grid electrodes
B- A combination hook and screw method
C- The supraliminal placement of rods
D- Severing the caudal equina

B- A combination hook and screw method

A patient in a state of surgical anesthesia using nitrous oxide is likely to have a drop in SSEP amplitudes of

A- 30%
B- 75%
C- 99%
D- 50%

B- 75%

What would you monitor for a microvascular decompression of the Vth nerve?

A- Lateral rectus
B- Quadriceps
C- Trapezuis
D- Masseter

D- Masseter

What electrode should be used for facial nerve CMAP recording?

A- Subdermal needle
B- Surface
C- Corkscrew
D- Hook wire

B- Surface

The most diagnostic part of the BAEP is:

A- Wave V latency
B- Wave I latency
C- Wave V amplitude
D- I-V interpeak

D- I-V interpeak

The intraoperative BAEP is most likely to be obscured by:

A- Eye movement
B- Patient position
C- Excessive Isoflurane
D- Muscle artifact

D- Muscle artifact

For peroneal nerve stimulation, the ground should be placed on:

A- The foot
B- the calf
C- the thigh
D- the ankle

C- the thigh

Upper Motor Neurons

A- Peroneal nerve
B- Dorsal nerve root
C- Cerebellum
D- Brainstem

D- Brainstem

During middle or posterior fossa surgery, what structure is most at risk?

A- Cerebellum
B- Spinal cord
C- Optic nerve
D- Brainstem

D- Brainstem

Spinal cord evoked potentials are best recorded using a low-frequency filter setting of 100 Hz. This setting is preferred because, relative to cortical somatosensory evoked potentials, spinal cord potentials are:

A- an extremely low voltage response
B- subject to 60 Hz interference
C- of relatively short duration
D- less affected by changes in anesthesia

C- of relatively short duration

A "false negative" test

A- means that the test results do not show an abnormality when a clinical abnormality is present
B- is the desired goal of the intraoperative monitoring staff
C- means that the test results show an abnormality when no clinical abnormality exists
D- presents the N18 wave as a positive down-going response

A- means that the test results do not show an abnormality when a clinical abnormality is present

With significant changes in cervical and cortical SSEPs during intraoperative monitoring, adequate stimulation of the median
nerve is indicated by

A- consistent anesthetic levels
B- a persistent thumb twitch
C- a loss of the peripheral response
D- no change in the peripheral responses

D- no change in the peripheral responses

The posterior tibial nerve arises from which branch of the sciatic nerve?

A- superior tibial
B- superior peronea
C- external popliteal
D- internal popliteal

A- superior tibial

Which of the following is a reason why a "false-negative" could occur?

A- The surgical procedure was revised due to data changes
B- The documentation was incomplete
C- No significant changes were noted and communicated
D- The lesion occurs in a structure not involved in the pathway being monitored

D- The lesion occurs in a structure not involved in the pathway being monitored

Subdermal needle electrodes must be inserted symmetrically over homologous brain areas to avoid:

A- artificial amplitude asymmetries
B- excessive high impedance
C- common mode rejection of the EEG signal
D- excessive bleeding

A- artificial amplitude asymmetries

Using a montage consisting of C5 spine to Fpz, with lower extremity stimulation, the expected response is generated at the

A- caudal medial lemniscus and is a far-field response
B- cervical spine and is a near-field potential
C- cervical spine and is a stationary potential
D- caudal medial lemniscus and is a stationary potential

A- caudal medial lemniscus and is a far-field response

Projecting laterally from the junction of the pedicle and lamina, and serving as a lever for muscle and ligaments, are the:

A- intervertebral foramen
B- intervertebral discs
C- transverse processes
D- mamillary processes

C- transverse processes

If all channels are showing excessive 60 Hz noise, what should you do?

A- Reboot the machine
B- Use a 60 Hz notch filter
C- Move your machine as far away from the patient as possible
D- Check your ground impedance

D- Check your ground impedance

Which of the following can inhibit the postsynaptic neuron

A- glutamate
B- para amino butyric acid
C- acetylcholine
D- gamma amino butyric acid

D- gamma amino butyric acid

When testing BAEPs you get a wave I on your contralateral ear montage. What do you do?

A- Don't do anything
B- Check ear inserts for proper side stimulation
C- Increase click intensity
D- Change polarity of click to condensation

B- Check ear inserts for proper side stimulation

The recommended location for recording the cervical cord response to median nerve stimulation is:

A- CS2
B- CS5
C- T2
D- CS1

B- CS5

When recording SSEP responses in an awake patient, the motor threshold should be the:

A- minimum stimulus intensity that produces a muscle twitch in the appropriate muscle group
B- stimulus rate at which tetany is achieved
C- threshold at which point the muscle groups being stimulated fail to respond to stimulation
D- level at which the patient can no longer tolerate the stimulus

A- minimum stimulus intensity that produces a muscle twitch in the appropriate muscle group

What significant EEG change would you expect to see with ischemia due to carotid clamping?

A- Increased fast activity
B- Increased slow activity
C- Spike discharges
D- Reduced background activity

B- Increased slow activity

CMAP responses to thoracic spinal cord stimulation should be recorded from:

A- Trapezuis
B- Obicularis oris
C- Quadriceps
D- Biceps

C- Quadriceps

The facial nerve is cranial nerve ___ and is supplies the muscle for _______.

A- VII, facial expression
B- V, jaw movement
C- VI , facial expression
D- V, eye movement

A- VII, facial expression

A goal of intraoperative monitoring of the sensory pathways is to

A- detect abnormalities (electrophysiologic changes) that develop as the recordings are taken
B- diagnose pre-existing abnormalities
C- differentiate between local surgical manipulations versus anesthetic affects
D- detect global systemic changes

A- detect abnormalities (electrophysiologic changes) that develop as the recordings are taken

A thoracic spinal fracture surgery should be monitored using:

A- Sural nerve
B- Ulnar nerve
C- Median nerve
D- Posterior tibial nerve

D- Posterior tibial nerve

For spinal cord monitoring using SSEPs, epidural electrodes should be placed:

A- Into the patient's external auditory canal
B- Rostral to the surgical site
C- Caudal to the surgical site
D- In the center of the surgical site

B- Rostral to the surgical site

The most important consideration for mapping of near field high voltage gradient signals is:

A- Comparison to scalp recorded signals
B- Contralateral to lateral chain setup
C- A quiet reference electrode position
D- Closely spaced electrodes

D- Closely spaced electrodes

"Signal-to-noise ratio" relates to which of the following?

A- The ability of the instrument to resolve data and noise vertically
B- Two inputs of a differential amplifier with like negativity
C- Sensitivity scaling
D- The amplitude of the evoked response components to the amplitude of the unrelated components

D- The amplitude of the evoked response components to the amplitude of the unrelated components

An advantage to using grid or strip electrodes over the "Crown of Thorns" for recording ECoG is the ability to:

A- place electrodes precisely on gyri
B- individually position each contact
C- slide them under the dura to unexposed areas
D- sterilize and reuse them

C- slide them under the dura to unexposed areas

Eliciting a motor twitch with PTN stimulation, you expect to see:

A- Dorsiflexion of the toes
B- Plantar flexion of the toes with eversion of the foot
C- Plantar flexion of the toes
D- Flexion of the abductor pollicis brevis

C- Plantar flexion of the toes

Cortical evoked potentials are largely produced by:

A- EPSPs and IPSPs
B- depolarization propagated along the nerve fibers
C- action potentials of the connecting axonal tracts
D- high energy magnetic fields of sodium ions within the cell membranes of the brain

A- EPSPs and IPSPs

Direct focal electrical stimulation of a peripheral nerve lesion will:

A- more precisely localize the distribution of intact conducting nerve fibers
B- be of no value
C- define epileptiform activity generated in the lesion
D- identify benign masses versus malignant tumor masses

A- more precisely localize the distribution of intact conducting nerve fibers

A decreasing body temperature of the surgical patient monitored with EPs can result in:

A- no remarkable changes
B- higher electrode impedances
C- increasing latencies of the SSEP and BAEP
D- increased amplitude of SSEP cortical responses

C- increasing latencies of the SSEP and BAEP

Reduction of the high frequency filter

A- increases evoked potential latency
B- has an unpredictable effect on evoked potential latency
C- decreases evoked potential latency
D- has no effect on evoked potential latency

A- increases evoked potential latency

Vertical resolution depends on:

A- Stimulation rate
B- Low cut filter
C- Number of bits
D- Input impedance

C- Number of bits

In order to record cortical SSEPs during intraoperative monitoring of the thoracolumbar spinal cord, an electrode should be placed:

A- 2 cm posterior to Pz
B- 2 cm anterior to Cz
C- 2 cm posterior to C3 and C4
D- 2 cm posterior to Cz

D- 2 cm posterior to Cz

Following the final application of corrective forces to the spinal column, the spinal cord should typically be monitored for at least:

A- 30 minutes
B- 5 minutes
C- 10 minutes
D- 20 minutes

A- 30 minutes

Meniere's Disease

A- Inner ear
B- Thalamus
C- Medial geniculate
D- Brainstem

A- Inner ear

A secure method for applying surface cup electrodes requires

A- water resistant tape
B- collodion and compressed air
C- a conductive paste and tape
D- application the day before surgery

B- collodion and compressed air

What is the minimum bandpass filter for an evoked potential system?

A- 100-3000 Hz
B- 0.1-5000 Hz
C- 0-100 Hz
D- 1000-10000 Hz

B- 0.1-5000 Hz

The vestibulocochlear nerve (CN VIII) appears:

A- between the cerebellum and C3
B- at the base of the brain near the optic nerves
C- from the floor of the third ventricle
D- in the groove between the pons and medulla oblongata

D- in the groove between the pons and medulla oblongata

Spinal cord ischemia during aortic surgery is best detected by changes in the

A- posterior tibial nerve somatosensory evoked potential
B- median nerve somatosensory evoked potential
C- lumber N20 spinal cord potential
D- tibial nerve compound action potential

A- posterior tibial nerve somatosensory evoked potential

For good recordings, you must have

A- Low input impedance, high electrode impedance
B- Low input impedance, low electrode impedance
C- High input impedance, high electrode impedance
D- High input impedance, low electrode impedance

D- High input impedance, low electrode impedance

This short acting, muscle relaxant is often used during intraoperative EMG monitoring:

A- succinylcholine
B- pancuronium
C- ethrane
D- robinol

A- succinylcholine

Given an electrical circuit with a resistance of 1000 ohms and a voltage of 10 volts, the current flow will be:

A- 0.10 ohms
B- 10 A
C- 100 volts
D- 0.01 A

D- 0.01 A

The resting membrane potential is created by differences between the inside and outside of the cell in ion concentrations of

A- Na+, Ca++, and C1-
B- K+
C- K+ and Ca++
D- K+, Na+, and C1-

D- K+, Na+, and C1-

What is the color code for Ground in an AC Power line?

A- White
B- Red
C- Green
D- Black

C- Green

The most critical event to monitor during CD instrumentation for scoliosis is:

A- Hook placement
B- Derotation
C- Graft placement
D- Placement of cross links

B- Derotation

PTN SSEPs can detect lesions of:

A- The pain pathways
B- Temperature receptors
C- Motor pathways
D- Proprioceptive fibers

D- Proprioceptive fibers

Why is changing filter parameters during intraoperative monitoring discouraged?

A- Because the surgeon will have to be informed
B- Because the machine will have to be rebooted
C- Because signal resolution may be affected
D- Because it may appear that a change has occurred due to surgery

D- Because it may appear that a change has occurred due to surgery

One difference between PTN and Peroneal responses is that Peroneal:

A- Is less affected by anesthesia
B- Has a longer latency
C- Has a shorter latency
D- Has a larger amplitude response

C- Has a shorter latency

In order to monitor cranial nerve X, the recording electrodes are placed on the:

A- false vocal cords
B- tongue
C- soft palate
D- trapezius muscle

A- false vocal cords

The EP monitoring team must

A- communicate on a regular basis and work in shifts throughout surgical procedures
B- include a medical engineer
C- include a neuroanesthesiologist
D- communicate any changes in the study and be able to solve technical difficulties

D- communicate any changes in the study and be able to solve technical difficulties

Which of the following will affect the facial nerve EMG?

A- Fentanyl
B- Methohexital
C- Isoflurane
D- Pancuronium

D- Pancuronium

Minimum Alveolar Concentration refers to the amount of anesthetic required to, in 50% of patients:

A- Prevent patient movement
B- Prevent patient recall
C- Reduce the evoked potentials to oblivion
D- Produce burst suppression

A- Prevent patient movement

The proper monitoring modalities for a C5-C6 cervical fracture surgery would be:

A- Posterior tibial and median nerves
B- Posterior tibial and peroneal nerves
C- Median and ulnar nerves
D- Ulnar and peroneal nerves

A- Posterior tibial and median nerves

The central conduction time for MN SSEP is:

A- Erb - N13
B- Erb - N20
C- P14 - N20
D- N20 - P23

C- P14 - N20

The innermost connective tissue membrane covering the brain is the

A- dura
B- falx cerebri
C- arachnoid
D- pia

D- pia

In a patient with hematocrit below 10%, the SSEP waveforms will

A- increase in latency and decrease in amplitude
B- increase in amplitude and increase in latency
C- cease to be recordable
D- have greater interpeak variability

A- increase in latency and decrease in amplitude

The amplitude of the cortical response to posterior tibial SEP stimulation is at least 80% attenuated by

A- a HLF of 5000 Hz
B- a stimulation duration greater than 150 microsec
C- stimulation rates of 15 per second or higher
D- large doses of muscle relaxant

C- stimulation rates of 15 per second or higher

Myogenic motor monitoring with spinal cord stimulation is most susceptible to:

A- Halothane
B- Sufentanil
C- Vecuronium
D- Isoflurane

C- Vecuronium

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

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

D- 10 - 2500 Hz

Hearing Level (HL) is defined by:

A- The average hearing threshold of a normal population
B- An individual's hearing threshold
C- Comparing the patient's threshold to a known pure tone
D- The absolute sound pressure relative to atmospheric pressure

A- The average hearing threshold of a normal population

During scoliosis surgery, the spinal cord is most at risk for injury

A- after the initial incision and at closing
B- during spinal distraction and sub laminar wiring
C- during hypotension induced by the anesthesiologist
D- at the start of the laminectomy

B- during spinal distraction and sub laminar wiring

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

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

A- 2 to 10 per second

With exposure provided by laminectomy, needle electrodes can record spinal activity with placement:

A- in the pedicle
B- in the epidural space
C- in the spinal muscle
D- on the spinal cord

B- in the epidural space

Universal precautions eliminate potential contact with body fluids that transmit:

A- electrical current
B- bacteriostatic viruses
C- bloodborne pathogens
D- meningitis

C- bloodborne pathogens

Using dissimilar metals within an electrode montage will result in:

A- Electrode polarization
B- Salt bridge
C- Low input impedance
D- High input impedance

A- Electrode polarization

Luque rods would be used

A- for posterior spinal fixation
B- to treat vascular compression of CN V
C- to repair an acetabular fracture
D- for anterior cervical fusion stabilization

A- for posterior spinal fixation

During microvascular decompression surgery to relieve a hemifacial spasm

A- Cz'-Fpz should be monitored for median nerve stimulation
B- a stimulation of CN VII elicits a response from the mental is muscle
C- it is necessary to monitor EMG from CN III
D- the buccal branch of CN V will likely show the most EMG activity

B- a stimulation of CN VII elicits a response from the mental is muscle

The prominent wave for monitoring of BAEPs is:

A- Wave I
B- ECoG
C- Wave III
D- Wave V

D- Wave V

Nyquist Frequency

A- Maximum stimulation repetition rate
B- Minimum sampling rate to prevent aliasing
C- One-half the highest frequency component of the signal measured
D- Minimum stimulation repetition rate

B- Minimum sampling rate to prevent aliasing

Severe hypothermia

A- has no effect on evoked potential latencies
B- decreases evoked potential latencies
C- has a variable effect on evoked potential latencies
D- increases evoked potential latencies

D- increases evoked potential latencies

Multiple sclerosis, spinal cord injury, and brain trauma can lead to debilitating spasticity that has been relieved in some patients following:

A- corpus callostomy
B- cortical stimulation
C- selective dorsal rhizotomy
D- posterior spinal fusion

C- selective dorsal rhizotomy