CNIM apparently on the actual test Solved 100% Correct 2023

An increase in stimulation intensity causes a linear increase of which of the following SSEP components? 1. N20 2. N45 3. P31 4. P37 - ANSWER-3. P31 Epidural electrodes are made of platinum because 1. It is the most durable metal 2. It is the lowest impedance metal 3. The chance of allergic reaction is eliminated 4. Other metals may become toxic when currents are applied - ANSWER-4. Other metals may become toxic when currents are applied 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 patients discomfort while maintaining adequate stimulation? 1. Increase stimulus duration 2. Use larger stimulating electrode 3. Use smaller stimulating electrode 4. Decrease stimulus intensity below motor threshold - ANSWER-2. Use larger stimulating electrode Which of the following would enhance wave I of the BAEP? 1. Increase the rate 2. Increase the intensity 3. Decrease the analysis time 4. Decrease the number of repetitions - ANSWER-2. Increase the intensity In BAEPs, wave I can most easily be differentiated from cochlear microphonics based upon 1. Amplitude 2. Morphology 3. Click polarity 4. Absence in contralateral recording - ANSWER-3. Click polarity What is the interstimulus interval of a 50 Hz click stimulus? 1. 0.02 msec 2. 0.20 msec 3. 0.50 msec 4. 20.00 msec - ANSWER-4. 20.00 msec Contralateral masking should be used during BAEPs to 1. Help the patient relax 2. Enhance wave I amplitude 3. Separate the IV/V complex 4. Prevent crossover responses - ANSWER-4. Prevent crossover responses The complete absence of a BAEP is most likely the result of 1. Sedation 2. Multiple sclerosis 3. Severe hearing loss 4. A normal age variant - ANSWER-3. Severe hearing loss Identification of wave V of the BAEP may require 1. Tympanic electrodes 2. Bilateral stimulation 3. Decreasing stimulus intensity 4. Use of a noncephalic reference - ANSWER-3. Decreasing stimulus intensity In spinal surgery, the primary purpose of the popliteal fossa recording electrode is to 1. Verify adequacy of stimulus 2. Limit current spread 3. Confirm amplifier integrity 4. Provide evidence of a muscle twitch - ANSWER-1. Verify adequacy of stimulus while performing a posterior tibial SSEP, hypothermia of the lower extremities is most likely to cause 1. Increased L3-P37 latency 2. Increased T12-P37 latency 3. Slowed peripheral conduction velocity 4. Abnormal prolongation of the P37-N45 complex - ANSWER-3. Slowed peripheral conduction velocity Which of the following peaks in tibial nerve SSEPs is most analogous to P14 of median nerve SSEP? 1. N20 2. N34 3. P31 4. P37 - ANSWER-3. P31 Which of the following devices measures electrode resistance? 1. Ammeter 2. Ohmmeter 3. Voltmeter 4. Photometer - ANSWER-2. Ohmmeter 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. 1:2 3. 2:1 4. 5:1 - ANSWER-3. 2:1 To display median nerve SSEP response as an upward deflection, which of the following must be known? 1. Waveform polarity and latency of the response 2. Waveform polarity and polarity convention of the amplifier inputs 3. Polarity convention of amplifier inputs and amplitude of the response 4. Latency of the response and polarity convention of the amplifier inputs - ANSWER-2. Waveform polarity and polarity convention of the amplifier inputs 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? 1. 10,000:1 2. 100,000:1 3. 500,000:1 4. 1,000,000:1 - ANSWER-4. 1,000,000:1 Which of the following cranial nerves innervated the extraocular muscles? 1. Optic 2. Facial 3. Abducens 4. Trigeminal - ANSWER-3. Abducens Which of the following is an example of an SSEP far-field subcortical potential? 1. N20 2. N34 3. Erbs point 4. Popliteal fossa - ANSWER-2. N34 Which of the following opposes any change in current? 1. Capacitance 2. Impedance 3. Inductance 4. Resistance - ANSWER-3. Inductance Which of the following electrode materials has little electrode potential drift and a long time constant? 1. Tin 2. Gold 3. Silver 4. Stainless steel - ANSWER-2. Gold Where should epidural electrodes be placed? 1. On the dura 2. In the spinal cord 3. Within the dural memebrane 4. Between the dura and the spinal cord - ANSWER-1. On the dura With referential recording, maximal amplitude cortical evoked potentials following stimulation of the left posterior tibial nerve usually would be found between 1. C3 and Cz 2. C4 and P4 3. Fz and Cz 4. C4 and Cz - ANSWER-1. C3 and Cz For preoperative posterior tibial somatosensory evoked potentials, which of the following would be the best ipsilateral location for the ground electrode? 1. Arm 2. Calf 3. Mastoid 4. Sole of the foot - ANSWER-2. Calf To record the afferent volley after posterior tibial nerve stimulation, an electrode should be placed on the 1. Patella 2. Metatarsal 3. Popliteal fossa 4. Medial malleolus - ANSWER-3. Poplilteal fossa Impedances of applied electrodes should be 1. Balanced and below 5,000 ohms 2. Balanced and above 5,000 ohms 3. Unbalanced and below 5,000 ohms 4. Unbalanced and above 5,000 ohms - ANSWER-1. Balanced and below 5,000 ohms During posterior fossa surgery, when BAEPs are used for monitoring brainstem function, it is most important to 1. Record cranial nerve VII action potentials 2. Monitor cranial nerve V function ipsilaterally 3. Stimulate and record from the operative side only 4. Stimulate and record from the contralateral side - ANSWER-4. Stimulate and record from the contralateral side Which of the following cranial nerves is most appropriate to monitor during resection of a 4 cm vestibular schwannoma? 1. Optic 2. Facial 3. Abducens 4. Oculomotor - ANSWER-2. Facial During carotid endarterectomy, what SSEP modality is recommended for monitoring cerebral function? 1. Femoral 2. Median 3. Posterior tibial 4. Common peroneal - ANSWER-2. Median If the EEG is preserved during carotid endarterectomy surgery, it indicates 1. Inadequate level of anesthesia 2. Diffuse neuronal dysfunction 3. Accurate electrode placement 4. Adequate cortical perfusion and oxengenation - ANSWER-4. Adequate cortical perfusion and oxengenation SSEPs to posterior tibial nerve stimulation are most appropriate to monitor during surgery for 1. Scoliosis 2. Hemifacial spasm 3. Middle cerebral artery aneurysm 4. Cerebellar pontine angle tumor - ANSWER-1. Scoliosis In recording electrocochleograms, it is best to stimulate using 1. Tone pips 2. Tone bursts 3. Alternating clicks 4. Rarefaction clicks and condensation - ANSWER-4. Rarefaction clicks and condensation A postincision baseline recording is used to 1. Evaluate homodynamic status 2. Determine long term prognosis 3. Establish a standard for the patient 4. Compare patient's values to laboratory normative data - ANSWER-3. Establish a standard for the patient 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? 1. N20 2. P22 3. Erbs point potential 4. Central conduction time - ANSWER-3. Erbs point potential