New Quiz 03 Jan Welcome to your Neurophysiology Name Email 1. [A patient is referred to the neuromuscular clinic for evaluation of a brachial plexopathy. On examination, he was noted to have weakness in the deltoid and triceps; however, the pronator teres muscle and biceps brachii were strong. Presuming that the pathology is in the brachial plexus, these findings are best localizable to which of the following structures?] Medial cord Lateral cord Posterior cord C5–C6 roots None . 2. [A 23-year-old woman presents to her neurologist with severe fatigue, generalized weakness, and occasional eye droop. To rule out myasthenia gravis (MG), repetitive stimulation of the spinal accessory nerve is done. The results of repetitive stimulation 2 minutes after exercise are shown below. What does it show? (fig)] Significant decrement in compound muscle action potential (CMAP) amplitude Mild increment in CMAP amplitude, which is normal No change in CMAP amplitude Repair suggestive of neuromuscular junction dysfunction None Comment . 3. [Intraoperative compromise to which of the following blood vessels is likely to be detected by monitoring somatosensory evoked potentials (SSEPs) during surgery?] Posterior inferior cerebellar artery Anterior spinal artery Posterior spinal artery Medial lenticulostriate artery None . 4. [A 20-year-old man suffered an injury while riding his bike. He developed weakness, pain, and sensory loss in the left upper limb. Nerve conduction studies performed a few weeks later revealed normal median motor and ulnar motor and sensory responses. Left lateral antebrachial antidromic sensory response was absent. Findings on needle EMG of selected muscles in the left upper limb are shown below. What is the most likely localization? (fig)] C5, C6, and C7 roots Upper trunk of brachial plexus Posterior cord of brachial plexus Lower trunk of brachial plexus None Comment . 5. [Which of the following determines the flow of ions across a channel?] Chemical gradient Electrical gradient Membrane conductance All of the above None . 6. [Ictal patterns at the onset of generalized tonic–clonic seizures include all of the following except] Voltage attenuation Paroxysmal beta activity Generalized polyspike-wave discharges Rhythmic 3 Hz sinusoidal activity None . 7. [Which of the following is the best test to differentiate Parkinson’s disease with autonomic failure from multiple system atrophy (MSA)?] Degree of orthostatic hypotension Heart rate (HR) variability Cardiac sympathetic imaging Valsalva ratio None . 8. [Widespread slow waves on the EEG can be seen in all of following states except] Hypocarbia (PaCO2 less than 40 mmHg) Severe hypotension IV etomidate induction Hypothermia at 20°C None . 9. [All of the following statements are true about the 3-hole electrical receptacle encountered in North America except] The short slot is “hot” The long slot is “neutral” The D-shaped slot is the “true ground” The wires from the long slot and the D-shaped slot together constitute the “true ground” None . 10. [Triphasic waves are characterized by all of the following except] Triphasic morphology with a prominent negative phase in the middle An antero-posterior lag Generalized bilaterally symmetric and synchronous distribution Monotonous waveforms with 1.5–2.5 Hz frequency and medium voltage None . 11. [A 65-year-old female with a history of congestive heart failure complicated by stroke reported frequent awakenings with shortness of breath and excessive daytime sleepiness. A Cheyne–Stokes breathing pattern was noted on the polysomnogram (PSG). Which of the following physiological features can be expected in this patient?] Accentuation of the abnormal breathing pattern during REM sleep PaCO2 greater than 45 mmHg Oxygen desaturation less than 80% Arousals at the end of apnea None . 12. [Which of the following is the earliest abnormal feature seen in nerve conduction studies in a patient with acute demyelinating polyneuropathy?] Decreased conduction velocity Absent sensory responses Delayed or absent F-wave responses Conduction block or abnormal temporal dispersion None . 13. [Which of the following statements is true regarding the use of chloral hydrate in recording EEG?] It can be routinely administered in most EEG laboratories It induces fast activity It is rapidly metabolized It can frequently cause paradoxical excitation and irrational behavior None . 14. [A 25-year-old male had an EEG (filter: 1–70 Hz; sensitivity: 5 μV/mm; the solid verticallines are 1 second apart) as part of the workup for syncope. During the recording asshown below, the technologist noted focal rhythmic activity in the left central region,which went away when the patient wiped his nose with his right hand. Which of thefollowing statements is true regarding this activity? (fig)] Its frequency is in the theta range Nose wiping with the right hand has no relation to the activity It represents the resting rhythm of the Rolandic cortex It represents a brief ictal discharge that may have originated in the temporal region None Comment . 15. [A 13-year-old boy had a seizure in the setting of playing a video game. When the neurophysiologist was reading his EEG, she saw that there were EEG changes during photic stimulation. All of the following statements correctly describe the possible changes that can be seen during photic stimulation except] Photoparoxysmal response (PPR) refers to any EEG change without clinical correlation Photoconvulsive response refers to spike-wave discharges correlated to clinical manifestations Photomyoclonic response refers to widespread muscle twitching timed to the stimulus representing a heightened brainstem-mediated reflex Photoelectric response refers to changes in the anterior channels that disappear with shielding the electrode from the light None . 16. [Acceptable methods for measuring the peak waveform amplitude of the somatosensory evoked potentials (SSEPs) during intraoperative monitoring (IOM) include all of the following except] With respect to the following peak of opposite polarity With respect to the preceding peak of opposite polarity With respect to the baseline level of the waveform preceding the peak With respect to the baseline level of the waveform following the peak None . 17. [Central conduction time (CCT) can be estimated by all of the following measurements except] P14–N20 interpeak interval (IPI) N13–N20 IPI N22–P31 IPI P31–P37 IPI None . 18. [Around 32–34 weeks of conceptional age, the background during active sleep (AS) and quiet sleep (QS) tends to be] Tracé discontinu in both states A more continuous pattern in AS and tracé discontinu in QS Tracé discontinu in AS and a more continuous pattern in QS More continuous patterns in both states None . 19. [When multiple capacitors are placed in a circuit, they exhibit the behavior opposite to that of] Inductors Resistors Invertors Operative amplifiers None . 20. [Which of the following features is characteristic of syncope?] Myoclonus tends to be multifocal Tonic activity tends to be more pronounced in syncope than in prolonged cerebral hypoxia Prolonged syncope is associated with postictal confusion lasting more than a minute EEG becomes flat at the onset of unconsciousness None . 21. [Which of the following studies is most likely to be abnormal in a patient with lengthdependent axonal polyneuropathy?] Peroneal motor amplitude Tibial motor amplitude Peroneal F-wave response Sural sensory response None . 22. [A median palmar mixed sensory study is shown below. Which part of the waveform isconsidered a far-field potential? (fig)] Stimulus artifact Sensory response Motor artifact after the sensory response Only the sensory amplitude None Comment . 23. [An 8-year-old has right eye blindness since birth. He fainted after playing outside in the summer. All of the following abnormalities can be expected on an EEG except] Left occipital spikes Slowing of the right posterior dominant rhythm (PDR) Loss of photic driving Loss of lambda waves None . 24. [What happens to the P100 latency of the visual evoked potential if the high-frequency filter cutoff is lowered?] There may be an apparent increase in the P100 latency There may be an apparent decrease in the P100 latency There will be no change in the apparent P100 latency There may be a bifid pattern of the peak latency None . 25. [All of the following statements are true about pattern reversal visual evoked potential (PRVEP) except] Larger check size distorts P100 waveform Faster reversal rate distorts P100 waveform Higher luminance increases P100 latency Higher luminance increases P100 amplitude None .
