CNIM - Evoked Potential

1. Which of the following devices measures electrode resistance? *

Ammeter Ohmmeter Voltmeter Photometer

2. If an evoked potential has a voltage of 10 uV and the associated noise has a voltage of 50 uV, what is the signal-to-noise ratio after 100 averaged responses? *

1:1 1:2 2:1 5:1

3. To display median nerve SSEP resonse as an upward deflection, which of the following must be known? *

Waveform polarity and latency of the response Waveform polarity and polarity convention of the amplifier inputs Polarity convention of amplifier inputs and amplitude of the response Latency of the response and polarity convention of the amplifier inputs

4. If an amplifier is rated as having 120 dB common mode rejection ratio, which of the following ratios of in-phase to out-of-phase signals would be expected? *

10,000:1 100,000:1 500,000:1 1,000,000:1

5. Which of the following cranial nerves innervates the extraocular muscles? *

Optic Facial Abducens Trigeminal

6. Which of the following is an example of an SSEP far-field subcortical potential? *

N20 N34 Erb's Point Popliteal Fossa

7. Which of the following opposes any change in current? *

Capacitance Impedance Inductance Resistance

8. Which of the following electrode materials has little electrode potential drift and a long time constant? *

Tin Gold Silver Stainless Steel

9. Where should epidural electrodes be placed? *

On the dura In the spinal cord Within the dural membrane Between the dura and the spinal cord

10. With referential recording, maximal amplitude cortical evoked potentials following stimulation of the left posterior tibial nerve usually would be found between *

C3 and CZ C4 and P4 FZ and CZ C4 and CZ

11. For preoperative posterior tibial somatosensory evoked potentials, which of the following would be the best ipsilateral location for the ground electrode? *

Forearm Calf Shoulder Palm

12. To record the afferent volley after posterior tibial nerve stimulation, an electrode should be placed on the *

Mastoid Erb's point C5 Spine Index finger

13. Impedances of applied electrodes should be *

balanced and below 5,000 ohms balanced and above 5,000 ohms unbalanced and below 5,000 ohms unbalanced and above 5,000 ohms

14. An increase in stimulation intensity causes a linear increase of which of the following SSEP components? *

N20 N45 P31 P37

15. Epidural electrodes are made of platinum because *

It is the most durable metal It is the lowest impedance metal The chance of allergic reaction is limited Other metals may become toxic when a current is applied.

16. During a median nerve preoperative study, a patient has discomfort at the wrist. Stimulation electrodes are 10 mm gold disk, stimulus intensity is 20 mA, and stimulus duration is 100 usec. Which of the following would most likely reduce the patient's discomfort while maintaining adequate stimulation? *

17. Which of the following would enhance wave I of the BAEP? *

Increase the rate Increase the intensity Decrease the analysis time Decrease the number of repetitions

18. In BAEPs, wave I can most easily be differentiated from cochlear microphonics based upon *

Amplitude Morphology Click Polarity Absence in contralateral recording

19. What is the interstimulus interval of a 50 Hz click stimulus? *

0.02 msec 0.2 msec 0.5 msec 20 msec

20. Contralateral masking should be used during BAEPs to *

help the patient relax enhance wave amplitude I separate the IV/V complex prevent crossover responses

21. The complete absence of a BAEP is most likely the result of *

sedation multiple sclerosis severe hearing loss a normal age variant

22. Identification of wave V of the BAEP may require *

tympanic electrodes bilateral stimulation decreasing stimulus intensity use of a noncephalic reference

23. In spinal surgery, the primary purpose of the popliteal fossa recording electrode is to *

verify adequacy of stimulus limit current speed confirm amplifier integrity provide evidence of a muscle twitch

24. While performing a posterior tibial SSEP, hypothermia of the lower extremities is most likely to cause *

increased L3-P37 latency increased T12-P37 latency slowed peripheral conduction velocity abnormal prolongation of the P37-N45 complex

25. Which of the following peaks in tibial nerve SSEPs is most analogous to P14 of median nerve SSEP *

N20 N34 P31 P37

29. The potential generator for B is most likely which structure? *

cortex thalamus cervical spinal cord brachial plexus

30. The potential generator for C is most likely which structure? *

cortex thalamus cervical spinal cord brachial plexus

31. The response component at A can best be described as *

far-field propagated near-field presynaptic

32. During posterior fossa surgery, when BAEPs are used for monitoring brainstem function, it is most important to *

record cranial nerve VIII action potentials monitor cranial nerve V function ipsilaterally stimulate and record from the operativeside only stimulate and record from the contralateral side

33. Which of the following cranial nerves is most appropriate to monitor during resection of a 4 cm vestibular schwannoma? *

Optic Facial Posterior tibial Common peroneal

34. During carotid endarterectomy, what SSEP modality is recommended for monitoring cerebral function? *

Femoral Median Posterior Tibial Common Peroneal

35. If the EEG is preserved during carotid endarterectomy surgery, it indicates *

inadequate level of anesthesia diffuse neuronal dysfunction accurate electrode placement adequate cortical perfusion and oxegynation

36. SSEPs to posterior tibial nerve stimulation are most appropriate to monitor during surgery for *

scoliosis hemi-facial spasm middle cerebral artery aneurysm cerebellar pontine angle tumor

37. In recording the auditory brainstem response, it is best to stimulate using *

tone pips tone bursts alternating clicks rarefaction clicks and condensation

38. A post-incision baseline recording is used to *

evaluate hemodynamic status determine long-term prognosis establish a standard for the patient compare patient's values to laboratory normative data

39. Which of the following would most likely be normal in the pre-operative baseline upper extremity SSEP of a patient with a lesion in the dorsal column? *

N20 P22 Erb's point Central conduction time

40. Selection of the nerve to be stimulated for preoperative baseline SSEPs is determined by the *

patient age surgical procedure dermatomal innervation anesthesiologist

41. For preoperative posterior tibial somatosensory evoked potentials, which of the following would be the best ipsilateral location for the ground electrode? *

Arm Calf Mastoid Sole of foot

42. To record the afferent volley during preoperative baseline studies after posterior tibial stimulation, an electrode should be placed on the *

patella metatarsal popliteal fossa medial malleolus

43. Routine intraoperative electrophysiological monitoring documentation should include *

heart rate blood pressure respiratory rate blood plasma volume

44. If a technologist accidentally touches a sterile table, which of the following is the most appropriate action? *

Change scrubs immediately Remain silent until procedure is completed Notify the scrub or circulating nurse at once Maintain safe distance from sterile field

45. In a bipolar montage, the key element in localization is the *

instrument phase reversal relative voltage in each channel common mode rejection of in-phase noise synchronization of discharges

46. Which option is a scalp to noncephalic reference *

Fz - C5S CPz - Fz EPi - EPc CPc - CPi

47. According to the ACNS guidelines, system bandpass settings for monitoring facial nerve spontaneous muscle activity should be *

1-250 to 1500 Hz 10-30 to 2500-3000 Hz 10-30 to 16,000 Hz 100-200 to 1000-3000 Hz

48. Harrington instrumentation includes *

rods pedicle screws sublaminal wires segmental wires

49. Intraoperative evoked potential monitoring criteria of abnormality are based on a comparison of amplitude and latency to *

preinduction baseline postincision baseline intraoperative normative data laboratory normative data

50. Which of the following anesthetic agents may increase the amplitude of cortical potentials? *

etomidate halothane pentobarbital nitrous oxide

Please submit your answers along with your name, email and any comments or questions below.