Welcome to your Neurophysiology Name Email 1. [All of the following statements about common mode signals are true except] Common mode signals are dissimilar potentials at different electrode sites that should be ideally rejected Amplifiers are designed to preferentially block common mode signals and to pass the differential-mode signals Unequal impedances between electrodes can affect common mode signals It is recommended that the common mode signals be rejected at a ratio of 80 dB None . 2. [A 25-year-old man developed a viral illness in the summer of 2012 followed by development of weakness in the left arm within a few weeks. On examination, he has severe weakness in the left hand and arm. A nerve conduction study performed 3 months later revealed the following findings. What is the most likely diagnosis? (fig )] Monomelic amyotrophy West Nile-associated poliomyelitis type syndrome Spinobulbar muscular atrophy (Kennedy’s disease) Early onset amyotrophic lateral sclerosis (ALS) None Comment . 3. [The P14 component of the median somatosensory evoked potential (SSEP) is] A near-field potential Best seen on the scalp with a cephalic reference Generated by activity in the medial lemniscus Preserved in cervicomedullary lesions None . 4. [After an extensive abdominal surgery, a 40-year-old woman developed significant weakness in her left thigh. Needle EMG performed a few months later revealed the following potentials during maximum activation. What is the firing frequency of the observed potential? (fig)] 5 Hz 7 Hz 10 Hz 14 Hz None Comment . 5. [A 6-year-old girl has multiple seizures that involve facial contraction. Her EEG showed centrotemporal spikes. Which part of the EEG is likely to demonstrate accentuation of these abnormalities?] Wakefulness Activation (photic stimulation or hyperventilation [HV]) NREM sleep REM sleep None . 6. [Compared to concentric EMG needles, monopolar needles have which of the following features?] Smaller motor unit potential amplitude Increased pain Increased variability of motor unit potentials Recording smaller area of muscle None . 7. [All of the following can occur with decreasing click intensity during brainstem auditory evoked potential (BAEP) recording except] Prolongation of interpeak latencies (IPLs) Prolongation of absolute latencies Decrease in amplitude Change in Wave I shape None . 8. [A 45-year-old man presents with weakness for more than 20 years. On examination, he has predominantly symmetrical, proximal more than distal, weakness with diminished reflexes and intact sensation. He was previously told that he had a form of muscular dystrophy. Needle EMG revealed few positive sharp waves and fibrillation potentials along with long-duration and large-amplitude motor unit potentials with severely reduced recruitment. If a muscle biopsy is performed in this patient, it will most likely reveal] Rimmed vacuoles Perifascicular atrophy Fiber type grouping Glycogen positive vacuoles None . 9. [In calculating impedance, the inductive reactance is subtracted from the capacitive reactance because] They have the same phase They have opposite phases The capacitive reactance already includes the inductive reactance The inductive reactance is not part of the overall impedance None . 10. [All of the following statements regarding the utility of somatosensory evoked potentials (SSEPs) during intraoperative monitoring (IOM) are true except] SSEPs are useful for monitoring during surgical lesioning of dorsal roots and dorsal root entry zone Postoperative SSEP amplitude reduction correlates with relief of pain and spasticity In addition to median and tibial nerves, pudendal nerve monitoring is important Monitoring of SSEPs does not have clinical utility in monitoring dorsal rhizotomy since the changes are inconsistent None . 11. [The low-frequency filter setting should be set at 0.5 Hz while performing which of the following tests?] Slow repetitive stimulation at 3 Hz Fast repetitive stimulation at 50 Hz Sympathetic skin response Blink or facial studies None . 12. [The slow waves seen in Stage N3 sleep have which of the following characteristics?] 0.5–3 Hz, greater than 100 μV 0.5–3 Hz, greater than 75 μV 0.5–2 Hz, greater than 75 μV 0.5–2 Hz, greater than 50 μV None . 13. [All of the following regarding Lennox–Gastaut syndrome (LGS) and juvenile myoclonic epilepsy (JME) are true except] Both have abnormal background The frequency of the spike-wave discharge is slower in LGS Both can present with polyspikes Only JME is felt to be idiopathic None . 14. [Which of the following parameters from the motor nerve conduction study is not used in the calculation of the F estimate?] Compound muscle action potential (CMAP) amplitude CMAP distal latency Conduction velocity Distance between stimulator electrode to the spinal cord None . 15. [Needle EMG of which of the following muscles would help differentiate L5 radiculopathy from peroneal mononeuropathy above the popliteal fossa?] Short head of biceps femoris Tibialis posterior Medial gastrocnemius Peroneus brevis None . 16. [All of the following statements regarding the mu rhythm are true except] The frequency tends to be in the theta range It is best seen over the central head regions It is associated with the sensorimotor cortex It is generally asymmetrical and asynchronous in distribution None . 17. [Which of the following is false regarding the action of sodium channels during an action potential?] They open in response to changes in membrane potential They operate in a feed-forward manner They close due to changes in calcium conductance They close due to intrinsic channel properties independent of membrane potential None . 18. [On postoperative day 2 after a renal transplant, a 12-year-old boy became febrile anddeveloped altered mental status. He was placed on antibiotics and continuous video-EEG monitoring was obtained as shown below (filter 1–70 Hz; sensitivity 10 μV/mm;solid vertical bars are 1 second apart). Six hours into the monitoring session, a relativelyabrupt decrease in EEG amplitude was seen as shown below. What is the most likelycause of the change? (fig)] Cessation of a generalized seizure discharge Suctioning the patient Cerebral hypoperfusion Turning off propofol None Comment . 19. [After a motor vehicle accident, a 40-year-old man develops weakness in the right arm and wrist drop. Evaluation in the emergency department reveals a fracture near the spiral groove. A radial motor study performed approximately 12 days after the accident reveals normal distal compound muscle action potential (CMAP) amplitude and absent response with stimulation above the spiral groove. These findings are most consistent with] Radial nerve transection at the spiral groove Radial nerve neuropraxia at the spiral groove Radial nerve neuropraxia in the forearm from the cast Radial nerve neurotmesis at the spiral groove None . 20. [The P100 waveform latency is increased by which of the following?] Low contrast; low luminance Low contrast; high luminance High contrast; low luminance High contrast; high luminance None . 21. [A 45-year-old man presents with a 5-year history of slowly progressive speech andswallowing difficulty. He recently noticed some limb weakness and this prompted areferral to a neuromuscular physician. On examination, he has dysarthria, flaccid limbweakness, decreased reflexes, and occasional fasciculations. Findings on sensory nerveconduction studies are shown below. Which of the following conditions does the patient most likely have? (fig)] Sporadic amyotrophic lateral sclerosis (ALS) Primary lateral sclerosis (PLS) Spinobulbar muscular atrophy Spinal muscular atrophy (SMA) None Comment . 22. [A 20-year-old college student presents with difficulty walking for 5 years but recently developed an increased tendency to trip and fall along with mild weakness in her hands. She also reports mild numbness in her feet. She denies any pain. Her birth and initial development were normal, but as a child she did not perform well in sports. On examination, cranial nerves are normal. Proximal limb strength is normal. She has distal weakness with bilateral foot drop and moderate finger extension and abduction weakness. She also has high-arched feet and atrophy of foot intrinsic muscles. Deep tendon reflexes are absent and there is lengthdependent sensory loss. What is the best neuroanatomical localization in the above patient?] Peripheral nerve and spinal cord Peripheral nerve and muscle Peripheral nerve only Muscle only None . 23. [A 33-year-old woman is being seen for a 1-month history of spells consisting of fall, impaired responsiveness, and shaking. Each spell lasts 2–3 minutes, and they occur multiple times daily. Prior routine EEG was normal. She is currently on carbamazepine. The most appropriate next step would be to] Repeat another routine EEG Stop carbamazepine Obtain inpatient video-EEG monitoring Add levetiracetam None . 24. [During a motor nerve conduction study, the sensitivity of the display was changed from 5 mV per division to 1 mV per division. How can this change affect the compound muscle action potential (CMAP)?] Increases the CMAP duration Increases the CMAP amplitude Increases the measured CMAP latency Decreases the measured CMAP latency None . 25. [Which of the following statements is true regarding P100 latency?] P100 latency tends to decrease with age P100 latency is shorter in men than women P100 latency is not affected by refractive errors P100 latency increases with decrease in pupillary diameter None .
