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Free CNIM Practice Questions

10 free, exam-style Certified in Neurophysiologic Intraoperative Monitoring (CNIM) practice questions with answers and explanations. No signup required. Work through them below, then take the full free CNIM practice test to study every exam domain.

These 10 free CNIM questions are organized by exam domain, so you can see how each part of the Certified in Neurophysiologic Intraoperative Monitoring blueprint is tested. Reveal the answer and explanation under each question.

Domain 1: Preparation and Application of Fundamental Concepts 25% of exam

Question 1

A patient undergoes thoracolumbar aortic aneurysm repair. Thirty minutes after aortic cross-clamping, bilateral lower extremity MEPs are lost while bilateral lower extremity SSEPs remain present and unchanged from baseline. Which anatomical explanation BEST accounts for these findings?

  1. The posterior spinal arteries have been occluded, disrupting dorsal column conduction while preserving corticospinal tract function
  2. Neuromuscular blockade was administered, abolishing all evoked potential responses distal to the neuromuscular junction
  3. The anterior spinal artery territory is ischemic, affecting the corticospinal tract while the posterior-column pathway remains perfused
  4. The artery of Adamkiewicz has been preserved, maintaining blood supply to both the anterior and posterior spinal cord
Show answer & explanation

Correct answer: C - The anterior spinal artery territory is ischemic, affecting the corticospinal tract while the posterior-column pathway remains perfused

Question 2

During cerebellopontine angle tumor resection, BAEP monitoring shows progressive loss of waves III through V while wave I remains stable and unchanged. This pattern is MOST consistent with compromise at the level of the:

  1. Cochlea and distal auditory nerve
  2. Primary auditory cortex in the temporal lobe
  3. Internal auditory canal affecting the labyrinthine artery
  4. Auditory brainstem pathways proximal to the cochlear nerve
Show answer & explanation

Correct answer: D - Auditory brainstem pathways proximal to the cochlear nerve

Question 3

A patient is scheduled for acoustic neuroma resection. To monitor the facial nerve intraoperatively, the CNIM technologist should place recording electrodes in the:

  1. Masseter and temporalis muscles
  2. Lateral rectus and superior oblique muscles
  3. Trapezius and sternocleidomastoid muscles
  4. Orbicularis oculi and orbicularis oris muscles
Show answer & explanation

Correct answer: D - Orbicularis oculi and orbicularis oris muscles

Domain 2: Intraoperative Phase 25% of exam

Question 4

During T4-L2 posterior spinal fusion, bilateral lower extremity cortical SSEPs show a 55% amplitude decrease with a 6% latency increase from baseline. Subcortical and peripheral responses remain stable. Upper extremity SSEPs are unchanged. Which statement BEST describes this situation?

  1. Both amplitude and latency criteria have been met; the surgical team should be notified immediately
  2. The amplitude criterion has been met, which alone warrants notification regardless of the latency value
  3. The latency criterion has not been met, so continued observation without notification is appropriate
  4. Bilateral changes always indicate a systemic cause, so anesthesia should be checked before any notification
Show answer & explanation

Correct answer: B - The amplitude criterion has been met, which alone warrants notification regardless of the latency value

Question 5

During scoliosis correction, the anesthesiologist administers a bolus of rocuronium to manage unexpected patient movement. Within minutes, bilateral MEPs and free-run EMG activity disappear while SSEPs and BAEPs remain unchanged. What is the MOST likely explanation?

  1. Spinal cord ischemia at the surgical correction level causing selective anterior motor pathway injury with preserved sensory function
  2. Increased depth of inhalational anesthesia suppressing cortical responses across all modalities
  3. Neuromuscular blockade abolishing myogenic responses while leaving sensory and auditory pathways intact
  4. A technical failure of the transcranial stimulator coinciding with loss of EMG amplifier function
Show answer & explanation

Correct answer: C - Neuromuscular blockade abolishing myogenic responses while leaving sensory and auditory pathways intact

Question 6

During lumbar pedicle screw placement at L4, stimulation of the newly placed screw elicits a compound muscle action potential in the tibialis anterior at a threshold of 4 mA. The MOST appropriate immediate action is to:

  1. Notify the surgeon of a likely pedicle wall breach and provide the threshold data
  2. Record the finding as within normal limits and continue monitoring
  3. Increase the stimulation rate to confirm the response before reporting
  4. Request that anesthesia administer a neuromuscular blocking agent to reduce background EMG noise
Show answer & explanation

Correct answer: A - Notify the surgeon of a likely pedicle wall breach and provide the threshold data

Question 7

During posterior fossa surgery, all SSEP and BAEP responses are suddenly lost across every channel. MEPs were not being recorded for this case. The technologist checks electrode impedances and finds them unchanged. Equipment connections and amplifier settings are verified as intact. What should the technologist do NEXT?

  1. Increase the number of signal averages to improve signal-to-noise ratio
  2. Apply a 60 Hz notch filter to all channels to eliminate potential interference
  3. Communicate the loss to the interpreting physician and surgical team while checking anesthetic and physiological variables
  4. Wait for two additional acquisition cycles to confirm the change is persistent and reproducible before notifying anyone on the surgical team
Show answer & explanation

Correct answer: C - Communicate the loss to the interpreting physician and surgical team while checking anesthetic and physiological variables

Domain 4: Provider Communication and Documentation 27% of exam

Question 8

During cervical spine surgery, a CNIM technologist observes a unilateral 70% SSEP amplitude decrease. After verifying the change is reproducible and ruling out technical causes, the surgeon asks the technologist whether the patient will have a neurological deficit. The technologist should:

  1. Provide a clinical interpretation since the data clearly indicates a neural injury
  2. Report the objective monitoring data and defer clinical interpretation to the interpreting physician
  3. Withhold the information until the interpreting physician is available to discuss it
  4. Advise the surgeon to reverse the last surgical maneuver based on the monitoring data
Show answer & explanation

Correct answer: B - Report the objective monitoring data and defer clinical interpretation to the interpreting physician

Question 9

During spinal cord tumor resection, a significant MEP amplitude decrease occurs at 14:32. The surgeon is notified verbally and pauses resection. The CNIM technologist's documentation entry for this event should include all of the following EXCEPT:

  1. The time the change was observed and the specific modality affected
  2. The names of all providers notified and their documented responses
  3. The surgical activity occurring at the time of the change
  4. A clinical diagnosis of spinal cord injury based on the MEP loss
Show answer & explanation

Correct answer: D - A clinical diagnosis of spinal cord injury based on the MEP loss

Domain 5: Safety and Ethics 10% of exam

Question 10

A patient with a central venous catheter is undergoing IOM with subdermal needle electrodes. The maximum allowable patient lead leakage current under normal operating conditions to prevent microshock risk is:

  1. 1 µA
  2. 10 µA
  3. 100 µA
  4. 500 µA
Show answer & explanation

Correct answer: B - 10 µA

The rest of the CNIM blueprint

The CNIM exam also covers these domains. Drill them in the full free practice test:

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