CNIM Instrumentation EXAM LATEST 2026-2027
120 QUESTIONS AND 100% Verified ANSWERS
When you have a salt bridge you will:
A- Be able to stimulate the underlying nerve better
B- Have difficulty stimulating the underlying nerve
C- Create a lethal pathway for current
D- Max out your impedances - answer>>B- Have difficulty stimulating the underlying nerve
If an evoked potential has a voltage of 10uV and the associated noise has a voltage of 50uV, what is the signal-
tonoiseratio after 100 averaged responses?
A- 2:1
B- 1:2
C- 5:1
D- 1:1 - answer>>A- 2:1
To display median nerve SSEP response as an upward deflection, which of the following must be known?
A- Polarity convention of amplifier inputs and amplitude of the response
B- Waveform polarity and polarity convention of the amplifier inputs
C- Latency of the response and polarity convention of the amplifier inputs
D- Waveform polarity and latency of the response - answer>>B- Waveform polarity and polarity convention of the
amplifier inputs
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- 10,000:1
B- 1,000,000:1
C- 500,000:1
D- 100,000:1 - answer>>B- 1,000,000:1
,Which of the following opposes any change in current?
A- Inductance
B- Resistance
C- Capacitance
D- Impedance - answer>>A- Inductance
According to the ACNS guidelines, system bandpass settings for monitoring facial nerve spontaneous muscle
activityshould be
A- 10‐30 to 16,000 Hz
B- 100‐200 to 1000‐3000 Hz
C- 1‐250 to 1500 Hz
D- 10‐30 to 2500‐3000 Hz - answer>>A- 10‐30 to 16,000 Hz
The unit for Impedance is:
A- Farads
B- Amperes
C- Ohms
D- Coulombs - answer>>C- Ohms
Artifact rejection:
A- Excludes trials with artifacts exceeding set amplitude values
B- Substitutes for common mode rejection
C- Eliminates all artifacts regardless of amplitude
D- Is needed only for intraoperative recordings - answer>>A- Excludes trials with artifacts exceeding set amplitude
values
If you need 100 trials to get a SNR of 2:1, how many trials are needed for a SNR of 20:1?
A- 20,000
, B- 10,000
C- 1000
D- 2000 - answer>>B- 10,000
What is the minimum sampling rate needed to identify an evoked potential containing 500 Hz frequency?
A- 500 Hz
B- 1000 Hz
C- 250 Hz
D- 750 Hz - answer>>B- 1000 Hz
Which is the minimum required CMRR?
A- 5000:1
B- 10,000:1
C- 100:1
D- 1000:1 - answer>>B- 10,000:1
A lab calibrated their 30db intensity to be 0db HL. If they stimulated a patient at 90db from their machines, what
would be the stimulus intensity?
A- 60 HL
B- 90 HL
C- 60 SL
D- 90 SL - answer>>A- 60 HL
Which is required to prevent aliasing of a signal?
A- Sampling below the Nyquist frequency
B- Sampling at least the Nyquist frequency
C- Use a stimulus frequency below the Nyquist
D- Setting the timebase to at least 100 mS - answer>>B- Sampling at least the Nyquist frequency
120 QUESTIONS AND 100% Verified ANSWERS
When you have a salt bridge you will:
A- Be able to stimulate the underlying nerve better
B- Have difficulty stimulating the underlying nerve
C- Create a lethal pathway for current
D- Max out your impedances - answer>>B- Have difficulty stimulating the underlying nerve
If an evoked potential has a voltage of 10uV and the associated noise has a voltage of 50uV, what is the signal-
tonoiseratio after 100 averaged responses?
A- 2:1
B- 1:2
C- 5:1
D- 1:1 - answer>>A- 2:1
To display median nerve SSEP response as an upward deflection, which of the following must be known?
A- Polarity convention of amplifier inputs and amplitude of the response
B- Waveform polarity and polarity convention of the amplifier inputs
C- Latency of the response and polarity convention of the amplifier inputs
D- Waveform polarity and latency of the response - answer>>B- Waveform polarity and polarity convention of the
amplifier inputs
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- 10,000:1
B- 1,000,000:1
C- 500,000:1
D- 100,000:1 - answer>>B- 1,000,000:1
,Which of the following opposes any change in current?
A- Inductance
B- Resistance
C- Capacitance
D- Impedance - answer>>A- Inductance
According to the ACNS guidelines, system bandpass settings for monitoring facial nerve spontaneous muscle
activityshould be
A- 10‐30 to 16,000 Hz
B- 100‐200 to 1000‐3000 Hz
C- 1‐250 to 1500 Hz
D- 10‐30 to 2500‐3000 Hz - answer>>A- 10‐30 to 16,000 Hz
The unit for Impedance is:
A- Farads
B- Amperes
C- Ohms
D- Coulombs - answer>>C- Ohms
Artifact rejection:
A- Excludes trials with artifacts exceeding set amplitude values
B- Substitutes for common mode rejection
C- Eliminates all artifacts regardless of amplitude
D- Is needed only for intraoperative recordings - answer>>A- Excludes trials with artifacts exceeding set amplitude
values
If you need 100 trials to get a SNR of 2:1, how many trials are needed for a SNR of 20:1?
A- 20,000
, B- 10,000
C- 1000
D- 2000 - answer>>B- 10,000
What is the minimum sampling rate needed to identify an evoked potential containing 500 Hz frequency?
A- 500 Hz
B- 1000 Hz
C- 250 Hz
D- 750 Hz - answer>>B- 1000 Hz
Which is the minimum required CMRR?
A- 5000:1
B- 10,000:1
C- 100:1
D- 1000:1 - answer>>B- 10,000:1
A lab calibrated their 30db intensity to be 0db HL. If they stimulated a patient at 90db from their machines, what
would be the stimulus intensity?
A- 60 HL
B- 90 HL
C- 60 SL
D- 90 SL - answer>>A- 60 HL
Which is required to prevent aliasing of a signal?
A- Sampling below the Nyquist frequency
B- Sampling at least the Nyquist frequency
C- Use a stimulus frequency below the Nyquist
D- Setting the timebase to at least 100 mS - answer>>B- Sampling at least the Nyquist frequency
