Welcome to your Neurophysiology Name Email 1. [Assume an EEG acquisition system that has a 10-bit analog-to-digital converter (ADC) with a voltage range of –2 mV to +2 mV. The voltage resolution of the sampled data is closest to which value?] 0.2 μV 2 μV 0.4 μV 4 μV None . 2. [Myogenic motor evoked potentials (mMEPs; M-waves) obtained by transcranial electrical stimulation (TES) during intraoperative monitoring (IOM) are] Caused by compound muscle action potentials within the muscle Recorded only by needle electrodes Resistant to anesthetic effects Resistant to neuromuscular blockade None . 3. [A 70-year-old man, suspected to have brachial plexopathy based on history and examination, underwent nerve conduction studies. Motor and sensory responses of themedian and ulnar nerves are summarized below. What is the most likely localization?(fig )] Upper trunk Medial cord Lateral cord C8 and T1 roots None Comment . 4. [Which thalamic nucleus helps in synchronization of EEG?] Reticular nucleus Anterior nucleus Pulvinar nucleus Medial geniculate nucleus None . 5. [Alexander disease is likely to be associated with which of the following EEG findings?] Bifrontal slowing Generalized periodic discharges (GPDs) Temporal spikes Burst suppression None . 6. [A 30-year-old woman was admitted for ascending weakness and numbness in her feet for 36 hours. She also reports severe back pain. On examination, she has distal and proximal weakness, diffuse areflexia, and distal sensory loss. An urgent electrodiagnostic study was requested. Which of the following components of the electrodiagnostic study is most likely to be abnormal in this patient?] Sural sensory response Peroneal motor response H-reflexes Blink responses None . 7. [A 30-year-old woman presented with recent onset difficulty speaking and swallowing. In addition, she has ptosis and diplopia. She was given pyridostigmine but her symptoms worsened with this medication. Repetitive stimulation of the spinal accessory nerve revealed significant decrement. Acetylcholine receptor (AChR) antibody test was normal. What is the next best diagnostic step?] Voltage-gated calcium channel antibody Muscle-specific kinase antibody Single-fiber EMG (SFEMG) Muscle biopsy to evaluate mitochondrial diseases None . 8. [A 43-year-old woman with lupus and hypertension presents for an EEG (filter: 1–70Hz), shown below after a witnessed seizure. Which of the following can be part of the patient’s ictal clinical semiology? (f 117)] Grunting Left hand dystonic posturing Bilateral asymmetric posturing Postictal nose wiping with the left hand None . 9. [A 30-second epoch of a polysomnogram (PSG) is shown below. What sleep stage is it?(fig)] Wake N1 N2 REM None Comment . 10. [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 . 11. [Decreased limb temperature may have the following effect on compound muscle action potential (CMAP) decrement on repetitive stimulation in a patient with myasthenia gravis] Increase in CMAP decrement Decrease in CMAP decrement Effect of decreased temperature on CMAP decrement is not predictable No change in CMAP decrement None . 12. [A 60-year-old man with weakness undergoes an ulnar motor study at baseline and after 15 seconds of exercise as shown below. What does it show? (fig)] Low compound muscle action potential (CMAP) amplitude at baseline and significant increment Low CMAP at amplitude at baseline and nonsignificant increment Normal CMAP at amplitude at baseline and significant increment Normal CMAP at amplitude at baseline and nonsignificant increment None Comment . 13. [Which of the following agents can increase the amplitude of cortical waveforms?] Nitrous oxide Etomidate Barbiturates Halothane None . 14. [What is the paroxysmal depolarization shift (PDS)?] The rising phase of the action potential A period of time when neurons are hyperpolarized A phenomena that helps to disrupt seizure propagation A wave of cortical depolarization, leading to synchronized neuronal spiking None . 15. [Which of the following EMG responses is generated from the motor unit?] Complex repetitive discharges Fibrillation potentials Myokymic discharges Myotonic discharges None . 16. [A 50-year-old male had intractable back pain and the diagnostic workup was significant for L3–L5 disc bulges. He underwent surgical decompression with intraoperative monitoring (IOM). All the baseline potentials were within normal limits. During the procedure, the N34 and P37/38 potentials disappeared with preservation of the N22 potential. What is the most appropriate localization?] Peripheral nerve Cauda equina Lumbar anterior horn cells Cortex None . 17. [The interface between the EEG electrode and the electrolyte paste can be considered as] An electrical double layer that presents capacitance impeding current flow Potentially unstable with new electrodes causing “pop” artifacts A source of half-cell potential that remains stable despite movement of the electrode Highly polarized when a silver–silver chloride interface is used None . 18. [Amplitude of EEG activity] Does not exceed 50 μV on the scalp Does not exceed 500 μV on electrocorticograms Is typically measured from peak to peak Needs to be accurately reported at least for the posterior dominant rhythm (PDR) None . 19. [Which of the following statements best describes the influence of physiologic factors on somatosensory evoked potential (SSEP)?] Children attain adult latency values by 15–17 years of age Hypothermia with core body temperature at 17°C abolishes all median SSEP waveforms Sleep does not affect the latencies Body height equally affects both absolute and interpeak latencies (IPLs) for tibial SSEPs None . 20. [The evolution of a drowsy pattern on EEG consists of all of the following except] Appearance of hypnagogic hypersynchrony by age 3 months Disappearance of hypnagogic hypersynchrony by age 2 years Dropout of the posterior dominant rhythm (PDR) by age 3 years Mature pattern with alpha dropout and diffuse low-voltage with intermixed slow and fast activity by adolescence None . 21. [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 . 22. [Which of the following findings on a muscle biopsy is characteristic of dermatomyositis?] Rimmed vacuoles Perifascicular atrophy Endomysial inflammatory infiltrates Myofiber necrosis None . 23. [All of the following statements are true about the generators of the tibial somatosensory evoked potential (SSEP) waveforms except] Lumbar potential (LP) is a near-field potential reflecting postsynaptic activity in the lumbar cord P31 is a far-field potential reflecting activity in the caudal medial lemniscus N34 is a near-field potential reflecting activity in the brainstem and thalamus P37 is a near-field potential reflecting activity in the parietal cortex recorded ipsilateral to the stimulated side None . 24. [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 . 25. [A 40-year-old man presents with a history of 2 generalized convulsions over a period of 3 days after sustaining a closed head injury. Since then, he has remained seizure free for 2 years on phenytoin monotherapy, and wants to discontinue the medication. His neurologic examination is normal. An appropriate recommendation would be to] Obtain a routine EEG prior to stopping phenytoin Stop phenytoin in the epilepsy-monitoring unit and obtain video-EEG monitoring for 1 week Taper off phenytoin without obtaining an EEG Change phenytoin to levetiracetam since it is better tolerated None .
