CNIM Practice 3 Exam Questions with correct Answers

Rostral to the cathode - Answer- For stimulation in MEP studies, the anode should be placed: A. rostral to the cathode B. lateral to the cathode C. Caudal to the cathode D. Medial to the cathode During anesthetic changes - Answer- Maximum variability of cortical EP potentials will most likely occur: A. After opening the surgical site B. During electrocautery C. Prior to lumbar laminectomy D. During anesthetic changes will increase the latency and decrease the amplitude of the ABR - Answer- Generally speaking, rate increases above 30 per second in ABR studies: A. Will increase the amplitude of wave V B. will decrease wave V amplitude and increase wave I amplitude C. Will increase the latency and decrease the amplitude of the ABR D. Have little or no effect on ABR responses 60 dB SL - Answer- IF a patient's hearing threshold is found to be 20 dB and then is tested at 80 dB, the intensity of the stimulus is: A. 80 dB SPL B. 60 dB HL C. 60 dB SL D. 80 dB SL Medial lemniscus - Answer- The earliest obligate component of the median nerve SSEP that is measured far-field is generated in the A. Thalamus B. Medial lemniscus C. Brachial Plexus D. Cerebral cortex Negative pole or black dot on the bar electrode - Answer- Cathode A. Negative pole or black dot on the bar electrode B. Positive pole or red dot on the bar electrode C. Used for recording EMG D. Positive input to the differential amplifier translation - Answer- Sublaminar wires are typically used to apply what type of corrective force to the spinal column A. Compression b. Translation C. Distraction D. Fixation EPSPs and IPSPs - Answer- Cortical evoked potentials are largely produced by A. high energy magnetic fields of sodium ions within the cell membranes of the brain B. action potentials of the connecting axonal tracts C. depolarization propagated along the nerve fibers D. EPSPs and IPSPs Surface - Answer- What electrode should be used for facial nerve CMAP recording? A. Subdermal needle B. Hook wire C. Corkscrew D. Surface signals via phase reversal - Answer- Bipolar electrodes are used for localization of A. Far field signals B. Phase changes in instrument C. Signals via phase reversal D. Decreased common mode rejection of relatively short duration - Answer- 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. less affected by changes in anesthesia D. of relatively short duration Salt bridge - Answer- Electrode gel in between the anode and cathode of the stimulating electrodes results in: A. High stimulating impedance B. Salt bridge C. Electrode polarization D. Improved stimulation 0.05 ms - Answer- A stimulus pulse width that would tend to excite a larger portion of motor fibers than sensory fibers is A. 1 ms B. 0.2 ms C. 0.05 ms D. 0.5 ms I-V interpeak - Answer- The most diagnostic part of the ABR is A. I-V interpeak B. Wave I latency C. Wave V latency D. wave V amplitude Minimum sampling rate to prevent aliasing - Answer- Nyquist frequency varies the current in order to maintain a preset voltage level - Answer- A constant voltage stimulator A. maintains a current level of 10 mA B. varies the output in order to maintain a preset current level C. Maintains a constant voltage of 100 volts D. Varies the current in order to maintain a preset voltage level 2 cm posterior to Cz - Answer- In order to record cortical SSEPs during IOM of the thoracolumbar spinal cord, an electrode should be placed: A. 2 cm posterior to Pz B. 2 cm posterior to Cz C. 2 cm anterior to Cz D. 2 cm posterior to C3 and C4 10 msec - Answer- What is the minimum acceptable sweep for ABRs Slightly increased latency, no change in amplitude - Answer- What is the effect on SSEPS of 50 ug/kg fentanyl? A. No change B. Slightly increased latency, no change in amplitude C. Decreased latency, increased amplitude D. Increased latency, decreased amplitude An electrical stimulator is required to pace the stimulus - Answer- All of the following are true of magnetic stimulation except A. The magnetic field created causes movement in cortical neurons B. An electrical stimulator is required to pace the stimulus C. THe stimulation is not perceived as painful D. Pulses of current are delivered through a coil of wire fluctuating amplitudes - Answer- An unstable blood pressure during SSEP monitoring in the OR affects cortical EPs resulting in A. Fluctuating amplitudes and latencies B. minimal changes if the body temperature is maintained C. fluctuating latencies D. fluctuating amplitudes Heating from the electrical cautery device - Answer- Early changes to CMAPs during the exposure of CN VII are most likely due to: A. severe blood loss B. Heating from the electrical cautery device C. Changes in the patient's state of consciousness D. An increase in inhalation agents impedance mismatch of the electrodes in that channel - Answer- Excessive 60 Hz noise on a single channel implies: A. poor stimulating impedance B. Impedance mismatch of the electrodes in that channel C. Chassis leakage may be outside acceptable values D. Poor ground impedance Increase noise - Answer- Loosely applied electrodes would cause: A. Decreased stim artifact B. Increased noise C. Increased low frequency response D. Decreased CMR P37 PTN - Answer- Which response depends most highly on the precision of electrode placement on the scalp? A. P37 PTN B. LP PTN C. Wave V ABR D. P14 MN Rostral to the surgical site - Answer- For spinal cord monitoring using SSEPs, epidural electrodes should be placed: A. In the center of the surgical site B. Rostral to the surgical site C. Caudal to the surgical site D. Into the patient's external auditory canal Proprioceptive fibers - Answer- PTN SSEPs can detect lesions of: A. the pain pathways B. Proprioceptive fibers C. motor pathways D. temperature receptors 75% - Answer- A patient in a state of surgical anesthesia using nitrous oxide is likely to have a drop in SSEP amplitudes of A. 99% B. 30% C. 50% D. 75% the antecubital fossa - Answer- To record the compound action potential of the median nerve IOM the electrode should be placed at A. C2 B. the shoulder C. the antecubital fossa D. the wrist 7 msec - Answer- The conduction time from the cervical response to the primary median nerve cortical response is: A. 4 msec B. 12 msec C. 2 msec D. 7 msec 200 Hz - Answer- If unavoidable muscle artifact is present in ABR you can change the locut filter to A. 200 Hz B. 10 Hz C. 1000 Hz D. 500 Hz prevent a flow of stray currents through connecting lines to the patient - Answer- The purpose of isolated amplifier inputs is to A. restrict current flow to the instrument B. allow only high voltage biological signals to pass C. restrict current flow to ground at 20 uA D. prevent a flow of stray currents through connecting lines to the patient 1000 Hz - Answer- Of the following, the peak equivalent SPL of a click should be calibrated at A. 5000 Hz B. 10000 Hz C. 500 Hz D. 1000 Hz Does not always indicate a good surgical outcome - Answer- Preservation of facial nerve CMAPs A. ensures motor activity of the jaw B. conclusively indicate preservation of function C. does not always indicate a good surgical outcome D. indicates postoperative function of cranial nerve VIII gamma amino butyric acid - Answer- Which of the following can inhibit the postsynaptic neuron A. Acetylcholine B. gamma amino butyric acid C. glutamate D. para amino butyric acid PTN SSEP - Answer- Spinal cord ischemia during aortic surgery is best detected by changes in the A. MN SSEP B. PTN SSEP C. Lumbar N20 spinal cord potential D. tibial nerve compound action potential 0.2 msec - Answer- With a sampling rate of 10 kHz the shortest sine wave resolved would be A. 0.02 msec B. 0.2 msec C. 0.4 msec D. 2 msec 40 to 100 uV/mm - Answer- Brain activity recorded directly from the cortex (ECoG) is very high in amplitude and usually requires sensitivities in the range of A. 40 to 100 uV/mm B. 200 to 300 uV/mm C. 100 to 500 uV/mm D. 10 to 50 uV/mm Cs5-Epc - Answer- What is the best montage to use to evaluate dorsal column activity? A. CPI-EPc B. Cs5-EPc C. CPc-EP D. EPi-EPc propofol - Answer- When used as an induction agent, which of the following drugs will have the least effect on the somatosensory evoked potential? A. Etomidate B. Isoflurane C. Propofol D. Halothane peak acoustic power of 2-4 kHz - Answer- The term "broadband click" refers to A. a peak acoustic power of 500 Hz to 2 kHz B. peak acoustic power of 2 - 4 kHz C. Short peak acoustic power of 1-2 kHz D. broad peak acoustic power of 1 - 5 kHz tongue - Answer- What muscle would you monitor for EMG activity for cranial nerve XII A. trapezius B. tongue C. masseter D. frontalis preserved during resection - Answer- Functional cortical stimulation is used to localize brain areas that must be A. monitored further by SSEPs B. preserved during resection C. identified before clamping D. most at risk during aneurysm clipping