CNIM PRACTICE EXAM 1 QUESTIONS
AND ANSWERS
During a median nerve preoperative study, a patient experiences discomfort at
the wrist. Stimulation electrodes are 10 mm gold disk, stimulus intensity is 20
mA, and stimulus duration is 100 μsec. Which of the following would most
likely decrease the patient's discomfort while maintaining adequate stimulation?
- ANSWER Decrease the number of repetitions
Which is not an advantage of epidural recordings? - ANSWER Absence of
significant artifact
Stimulation rate is determined by the - ANSWER analysis time
Somatosensory evoked potentials are less reliable in patients with? - ANSWER
Neuromuscular disease
When placing the PTN stimulator you should not - ANSWER Secure the tape
and bands around the whole ankle
A differential amplifier with a Gain of 1,000,000 has a 0.2 μV signal at its
positive input and a 0.8 μV signal at its negative input. The output will be: -
ANSWER A downward peak of 0.6V
The lumbar potential is generated from - ANSWER Post-synaptic responses
The P31 response to posterior tibial nerve stimulation - ANSWER Is
recordable over a generalized region of scalp
Which one of the following has the most profound effect on SEP monitoring? -
ANSWER Sevoflurane
A sense of shock passing across the body and occurring with neck flexion is
termed as - ANSWER L'Hermittes sign
Decreasing the SSEP hicut filter from 500 Hz to 200 Hz may make the cortical
peaks: - ANSWER Appear longer in latency
How many waves of a 60 Hz signal should you see in a 250 mS sweep? -
ANSWER 15
,Activation of an action potential of a neuron will depend on: - ANSWER Its
membrane potential based on the spatiotemporal summation of its excitatory
and inhibitory inputs
From left to right pre-auricular points is measured 30 cm. The C3 electrode is
located: - ANSWER 9 cm medial to the left pre-auricular point
The most frequent source of patient infection in the operating room derives
from: - ANSWER The patient's own endogenous flora
What is the maximum time in which to expect EEG changes following cross-
clamping of the carotid? - ANSWER Two minutes
Cranial nerve IV can be monitored using electrodes inserted into the -
ANSWER Superior oblique
According to the nurses guidelines how far do you need to be from the sterile
field? - ANSWER 18 inches
When a cortical grid is recorded in anterior-posterior orientation there is no
phase reversal: - ANSWER The maximum amplitude response is near the
central sulcus
At what temperature of the body does EEG disappear - ANSWER 16 degrees
C
By what means can an epileptiform discharge be localized: - ANSWER A
phase reversal between two channels
Why is platinum used in epidural recordings - ANSWER Other metals become
toxic when current is applied to them due to the ionic
What will most likely effect SSEPs? - ANSWER Spinal cord tumor
Excessive cerumen may cause - ANSWER Absence of the BAER
, Which of the following can increase SEP amplitude? - ANSWER Etomidate
Which of the following montages would you use to confirm a change in the Cz'-
Fz cortical response to PTN stimulation? - ANSWER Cpc-Cpi
CNS depressants cause: - ANSWER Minimal effects in ABRs
After-discharges occur after what? - ANSWER Direct cortical stimulation
An ABR has a normal wave one and then delayed wave I-V on one side. What
type of surgery is this most consistent with? - ANSWER CPA Tumor
An optimal repetition rate for BAEP's is - ANSWER 31Hz
The input impedance of a differential amplifier should be: - ANSWER At least
100 Megaohms
Lower motor neurons mainly leave the spinal cord through: - ANSWER
Ventral nerve roots
Absence of after-discharges suggests: - ANSWER The stimulus is probably
below the seizure activation threshold
There were epidural recordings to PTN stim from T5 and from C7. The T5 had
a stable response throughout the tumor surgery, while the C7 had no response
and then a great one after the tumor removal. Where was the tumor? -
ANSWER Rostral to T6 and caudal to C7
AND ANSWERS
During a median nerve preoperative study, a patient experiences discomfort at
the wrist. Stimulation electrodes are 10 mm gold disk, stimulus intensity is 20
mA, and stimulus duration is 100 μsec. Which of the following would most
likely decrease the patient's discomfort while maintaining adequate stimulation?
- ANSWER Decrease the number of repetitions
Which is not an advantage of epidural recordings? - ANSWER Absence of
significant artifact
Stimulation rate is determined by the - ANSWER analysis time
Somatosensory evoked potentials are less reliable in patients with? - ANSWER
Neuromuscular disease
When placing the PTN stimulator you should not - ANSWER Secure the tape
and bands around the whole ankle
A differential amplifier with a Gain of 1,000,000 has a 0.2 μV signal at its
positive input and a 0.8 μV signal at its negative input. The output will be: -
ANSWER A downward peak of 0.6V
The lumbar potential is generated from - ANSWER Post-synaptic responses
The P31 response to posterior tibial nerve stimulation - ANSWER Is
recordable over a generalized region of scalp
Which one of the following has the most profound effect on SEP monitoring? -
ANSWER Sevoflurane
A sense of shock passing across the body and occurring with neck flexion is
termed as - ANSWER L'Hermittes sign
Decreasing the SSEP hicut filter from 500 Hz to 200 Hz may make the cortical
peaks: - ANSWER Appear longer in latency
How many waves of a 60 Hz signal should you see in a 250 mS sweep? -
ANSWER 15
,Activation of an action potential of a neuron will depend on: - ANSWER Its
membrane potential based on the spatiotemporal summation of its excitatory
and inhibitory inputs
From left to right pre-auricular points is measured 30 cm. The C3 electrode is
located: - ANSWER 9 cm medial to the left pre-auricular point
The most frequent source of patient infection in the operating room derives
from: - ANSWER The patient's own endogenous flora
What is the maximum time in which to expect EEG changes following cross-
clamping of the carotid? - ANSWER Two minutes
Cranial nerve IV can be monitored using electrodes inserted into the -
ANSWER Superior oblique
According to the nurses guidelines how far do you need to be from the sterile
field? - ANSWER 18 inches
When a cortical grid is recorded in anterior-posterior orientation there is no
phase reversal: - ANSWER The maximum amplitude response is near the
central sulcus
At what temperature of the body does EEG disappear - ANSWER 16 degrees
C
By what means can an epileptiform discharge be localized: - ANSWER A
phase reversal between two channels
Why is platinum used in epidural recordings - ANSWER Other metals become
toxic when current is applied to them due to the ionic
What will most likely effect SSEPs? - ANSWER Spinal cord tumor
Excessive cerumen may cause - ANSWER Absence of the BAER
, Which of the following can increase SEP amplitude? - ANSWER Etomidate
Which of the following montages would you use to confirm a change in the Cz'-
Fz cortical response to PTN stimulation? - ANSWER Cpc-Cpi
CNS depressants cause: - ANSWER Minimal effects in ABRs
After-discharges occur after what? - ANSWER Direct cortical stimulation
An ABR has a normal wave one and then delayed wave I-V on one side. What
type of surgery is this most consistent with? - ANSWER CPA Tumor
An optimal repetition rate for BAEP's is - ANSWER 31Hz
The input impedance of a differential amplifier should be: - ANSWER At least
100 Megaohms
Lower motor neurons mainly leave the spinal cord through: - ANSWER
Ventral nerve roots
Absence of after-discharges suggests: - ANSWER The stimulus is probably
below the seizure activation threshold
There were epidural recordings to PTN stim from T5 and from C7. The T5 had
a stable response throughout the tumor surgery, while the C7 had no response
and then a great one after the tumor removal. Where was the tumor? -
ANSWER Rostral to T6 and caudal to C7
